2021 |
Ong LK, Briggs GD, Guan L, Dunkley PR, Dickson PW, 'Peripheral inflammation induces long-term changes in tyrosine hydroxylase activation in the substantia nigra', NEUROCHEMISTRY INTERNATIONAL, 146 (2021) [C1]
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Nova |
2019 |
Shehadeh J, Double KL, Murphy KE, Bobrovskaya L, Reyes S, Dunkley PR, et al., 'Expression of tyrosine hydroxylase isoforms and phosphorylation at serine 40 in the human nigrostriatal system in Parkinson's disease', Neurobiology of Disease, 130 (2019) [C1]
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Nova |
2019 |
Dunkley PR, Dickson PW, 'Tyrosine hydroxylase phosphorylation in vivo', Journal of Neurochemistry, 149 706-728 (2019) [C1]
Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the synthesis of the catecholamines dopamine, noradrenaline and adrenaline. One of the major mechanisms for controlling th... [more]
Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the synthesis of the catecholamines dopamine, noradrenaline and adrenaline. One of the major mechanisms for controlling the activity of TH is protein phosphorylation. TH is phosphorylated at serine residues 8, 19, 31 and 40. There have been a number of previous reviews focused on TH phosphorylation in¿vitro and in¿situ. This review on TH phosphorylation in¿vivo has three main sections focusing on: (1) the methods used to investigate TH phosphorylation in¿vivo, including the animals used, the sacrifice procedures, the tissue preparation, the measurement of TH protein levels and TH phosphorylation and the measurement of TH activation. (2) The regulation of TH phosphorylation and its consequences in¿vivo, including the kinases and phosphatases acting on TH, the stoichiometry of TH phosphorylation, the proteins that bind TH and TH subcellular location. (3) The acute and prolonged TH phosphorylation changes in specific catecholaminergic tissues, including the adrenal medulla, the nigrostriatal pathway and the mesolimbic pathway. (Figure presented.).
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Nova |
2019 |
Kunzler A, Garcia Sobrinho P, Smith T, Gelain DP, Moreira JCF, Dunkley PR, Dickson PW, 'Subcellular distribution of human tyrosine hydroxylase isoforms 1 and 4 in SH-SY5Y cells', Journal of Cellular Biochemistry, 120 19730-19737 (2019) [C1]
Tyrosine hydroxylase (TH) is the key enzyme that controls the rate of synthesis of the catecholamines. SH-SY5Y cells with stable transfections of either human tyrosine hydroxylase... [more]
Tyrosine hydroxylase (TH) is the key enzyme that controls the rate of synthesis of the catecholamines. SH-SY5Y cells with stable transfections of either human tyrosine hydroxylase isoform 1 (hTH1) or human tyrosine hydroxylase isoform 4 (hTH4) were used to determined the subcellular distribution of TH protein and phosphorylated TH, under basal conditions and after muscarine stimulation. Muscarine was previously shown to increase the phosphorylation of only serine 19 and serine 40 in hTH1 cells. Under basal conditions, the hTH1 and hTH4 proteins, their serine 19 phosphorylated forms and hTH1 phosphorylated at serine 40 were all similarly distributed; with ~80% in the cytosolic fraction, ~20% in the membrane fraction, and less than 1%, or not detectable, in the nuclear fraction. However, hTH4 phosphorylated at serine 71 had a significantly different distribution with ~65% cytosolic and ~35% membrane associated. Muscarine stimulation led to hTH1 being redistributed from the cytosol and nuclear fractions to the membrane fraction and hTH4 being redistributed from the cytosol to the nuclear fraction. These muscarine stimulated redistributions were not due to TH phosphorylation at serine 19, serine 40, or serine 71 and were most likely due to TH binding to proteins whose phosphorylation was increased by muscarine. This is the first study to show a difference in subcellular distribution between two human TH isoforms under basal and stimulated conditions.
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Nova |
2018 |
Hollins SL, Brock L, Barreto R, Harms L, Dunn A, Garcia-Sobrinho P, et al., 'A rodent model of anxiety: The effect of perinatal immune challenges on gastrointestinal inflammation and integrity', NeuroImmunoModulation, 25 163-175 (2018) [C1]
Objectives: Gastrointestinal (GI) inflammation and GI integrity deficits are common comorbidities of neuropsychiatric disorders. Ongoing research suggests that these aberrations m... [more]
Objectives: Gastrointestinal (GI) inflammation and GI integrity deficits are common comorbidities of neuropsychiatric disorders. Ongoing research suggests that these aberrations may be contributing to heightened immune signals that have the potential to disrupt neuronal homeostasis and exacerbate behavioural deficits. The current study aimed to determine whether the well-characterized animal model of neuropsychopathology, the maternal immune activation (MIA) model, produced GI inflammation and integrity disruptions in association with anxiety-like behaviour. Methods: Pregnant Wistar rats were exposed to the viral mimetic polyriboinosinic:polyribocytidilic acid (polyI:C) on gestational days (GD) 10 and 19. Evidence of ANS activation, GI inflammation, and GI barrier integrity was assessed in both neonatal (postnatal day, P7) and adult (P84) offspring. Anxiety-like behaviour was assessed at P100. Results: Neonatal MIA offspring exhibited an altered intestinal inflammatory profile and evidence of an increase in lymphoid aggregates. MIA neonates also displayed disruptions to GI barrier tight junction protein mRNA. In addition, adult MIA offspring exhibited an increase in anxiety-like behaviours. Conclusion: These results indicate that the MIA rat model, which is well documented to produce behavioural, neurochemical, and neuroanatomical abnormalities, also produces GI inflammation and integrity disruptions. We suggest that this model may be a useful tool to elucidate biological pathways associated with neuropsychiatric disorders.
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Nova |
2018 |
Sominsky L, Ong LK, Ziko I, Dickson PW, Spencer SJ, 'Neonatal overfeeding increases capacity for catecholamine biosynthesis from the adrenal gland acutely and long-term in the male rat', Molecular and Cellular Endocrinology, 470 295-303 (2018) [C1]
A poor nutritional environment during early development has long been known to increase disease susceptibility later in life. We have previously shown that rats that are overfed a... [more]
A poor nutritional environment during early development has long been known to increase disease susceptibility later in life. We have previously shown that rats that are overfed as neonates (i.e. suckled in small litters (4 pups) relative to control conditions (12 pups)) show dysregulated hypothalamic-pituitary-adrenal axis responses to immune stress in adulthood, particularly due to an altered capacity of the adrenal to respond to an immune challenge. Here we hypothesised that neonatal overfeeding similarly affects the sympathomedullary system, testing this by investigating the biochemical function of tyrosine hydroxylase (TH), the first rate-limiting enzyme in the catecholamine synthesis. We also examined changes in adrenal expression of the leptin receptor and in mitogen-activated protein kinase (MAPK) signalling. During the neonatal period, we saw age-dependent changes in TH activity and phosphorylation, with neonatal overfeeding stimulating increased adrenal TH specific activity at postnatal days 7 and 14, along with a compensatory reduction in total TH protein levels. This increased TH activity was maintained into adulthood where neonatally overfed rats exhibited increased adrenal responsiveness 30 min after an immune challenge with lipopolysaccharide, evident in a concomitant increase in TH protein levels and specific activity. Neonatal overfeeding significantly reduced the expression of the leptin receptor in neonatal adrenals at postnatal day 7 and in adult adrenals, but did not affect MAPK signalling. These data suggest neonatal overfeeding alters the capacity of the adrenal to synthesise catecholamines, both acutely and long term, and these effects may be independent of leptin signalling.
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Nova |
2017 |
Rostas JAP, Spratt NJ, Dickson PW, Skelding KA, 'The role of Ca
Studies in multiple experimental systems show that Ca2+-calmodulin stimulated protein kinase II (CaMKII) is a major mediator of ischaemia-induced cell death and suggest that CaMKI... [more]
Studies in multiple experimental systems show that Ca2+-calmodulin stimulated protein kinase II (CaMKII) is a major mediator of ischaemia-induced cell death and suggest that CaMKII would be a good target for neuroprotective therapies in acute treatment of stroke. However, as CaMKII regulates many cellular processes in many tissues any clinical treatment involving the inhibition of CaMKII would need to be able to specifically target the functions of ischaemia-activated CaMKII. In this review we summarise new developments in our understanding of the molecular mechanisms involved in ischaemia-induced CaMKII-mediated cell death that have identified ways in which such specificity of CaMKII inhibition after stroke could be achieved. We also review the mechanisms and phases of tissue damage in ischaemic stroke to identify where and when CaMKII-mediated mechanisms may be involved.
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Nova |
2017 |
Rostas JAP, Hoffman A, Murtha LA, Pepperall D, McLeod DD, Dickson PW, et al., 'Ischaemia- and excitotoxicity-induced CaMKII-Mediated neuronal cell death: The relative roles of CaMKII autophosphorylation at T286 and T253', Neurochemistry International, 104 6-10 (2017) [C1]
Ischaemia/excitotoxicity produces persistent activation of CaMKII (Ca2+-calmodulin stimulated protein kinase II) that initiates cell death. This study investigated the involvement... [more]
Ischaemia/excitotoxicity produces persistent activation of CaMKII (Ca2+-calmodulin stimulated protein kinase II) that initiates cell death. This study investigated the involvement of CaMKII phosphorylation at T286 and T253 in producing this persistent activation. In T286A-aCaMKII transgenic mice that lack the ability to phosphorylate aCaMKII at T286, transient occlusion of the middle cerebral artery for 90¿min resulted in no significant difference in infarct size compared to normal littermate controls. Overexpression of the phospho-mimic mutant T286D-aCaMKII in differentiated neuroblastoma cell lines did not enhance excitotoxicity-induced cell death compared to overexpression of wild type aCaMKII. By contrast, overexpression of the phospho-mimic mutant T253D-aCaMKII significantly enhanced excitotoxicity-induced cell death whereas overexpression of the phospho-null mutant T253V-aCaMKII produced no enhancement. These results indicate that T286 phosphorylation does not play a significant role in ischaemia/excitotoxicity induced CaMKII-mediated cell death and suggest that T253 phosphorylation is required to produce the persistent activation of CaMKII involved in ischaemia/excitotoxicity induced cell death.
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Nova |
2017 |
Ong LK, Fuller EA, Sominsky L, Hodgson DM, Dunkley PR, Dickson PW, 'Early life peripheral lipopolysaccharide challenge reprograms catecholaminergic neurons', SCIENTIFIC REPORTS, 7 (2017) [C1]
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Nova |
2017 |
Ong LK, Page S, Briggs GD, Guan L, Dun MD, Verrills NM, et al., 'Peripheral Lipopolysaccharide Challenge Induces Long-Term Changes in Tyrosine Hydroxylase Regulation in the Adrenal Medulla', Journal of Cellular Biochemistry, 118 2096-2107 (2017) [C1]
Immune activation can alter the activity of adrenal chromaffin cells. The effect of immune activation by lipopolysaccharide (LPS) on the regulation of tyrosine hydroxylase (TH) in... [more]
Immune activation can alter the activity of adrenal chromaffin cells. The effect of immune activation by lipopolysaccharide (LPS) on the regulation of tyrosine hydroxylase (TH) in the adrenal medulla in vivo was determined between 1 day and 6 months after LPS injection. The plasma levels of eleven cytokines were reduced 1 day after LPS injection, whereas the level for interleukin-10 was increased. The levels of all cytokines remained at control levels until 6 months when the levels of interleukin-6 and -4 were increased. One day after LPS injection, there was a decrease in TH-specific activity that may be due to decreased phosphorylation of serine 31 and 40. This decreased phosphorylation of serine 31 and 40 may be due to an increased activation of the protein phosphatase PP2A. One week after LPS injection, there was increased TH protein and increased phosphorylation of serine 40 that this was not accompanied by an increase in TH-specific activity. All TH parameters measured returned to basal levels between 1 month and 3 months. Six months after injection there was an increase in TH protein. This was associated with increased levels of the extracellular regulated kinase isoforms 1 and 2. This work shows that a single inflammatory event has the capacity to generate both short-term and long-term changes in TH regulation in the adrenal medulla of the adult animal. J. Cell. Biochem. 118: 2096¿2107, 2017. © 2016 Wiley Periodicals, Inc.
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Nova |
2017 |
Ong LK, Zhao Z, Kluge M, TeBay C, Zalewska K, Dickson PW, et al., 'Reconsidering the role of glial cells in chronic stress-induced dopaminergic neurons loss within the substantia nigra? Friend or foe?', Brain, Behavior, and Immunity, 60 117-125 (2017) [C1]
Exposure to psychological stress is known to seriously disrupt the operation of the substantia nigra (SN) and may in fact initiate the loss of dopaminergic neurons within the SN. ... [more]
Exposure to psychological stress is known to seriously disrupt the operation of the substantia nigra (SN) and may in fact initiate the loss of dopaminergic neurons within the SN. In this study, we aimed to investigate how chronic stress modified the SN in adult male mice. Using a paradigm of repeated restraint stress (an average of 20¿h per week for 6¿weeks), we examined changes within the SN using western blotting and immunohistochemistry. We demonstrated that chronic stress was associated with a clear loss of dopaminergic neurons within the SN. The loss of dopaminergic neurons was accompanied by higher levels of oxidative stress damage, indexed by levels of protein carbonylation and strong suppression of both microglial and astrocytic responses. In addition, we demonstrated for the first time, that chronic stress alone enhanced the aggregation of a-synuclein into the insoluble protein fraction. These results indicate that chronic stress triggered loss of dopaminergic neurons by increasing oxidative stress, suppressing glial neuroprotective functions and enhancing the aggregation of the neurotoxic protein, a-synuclein. Collectively, these results reinforce the negative effects of chronic stress on the viability of dopaminergic cells within the SN.
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Nova |
2017 |
Gasparotto J, Ribeiro CT, Bortolin RC, Somensi N, Fernandes HS, Teixeira AA, et al., 'Anti-RAGE antibody selectively blocks acute systemic inflammatory responses to LPS in serum, liver, CSF and striatum', Brain, Behavior, and Immunity, 62 124-136 (2017) [C1]
Systemic inflammation induces transient or permanent dysfunction in the brain by exposing it to soluble inflammatory mediators. The receptor for advanced glycation endproducts (RA... [more]
Systemic inflammation induces transient or permanent dysfunction in the brain by exposing it to soluble inflammatory mediators. The receptor for advanced glycation endproducts (RAGE) binds to distinct ligands mediating and increasing inflammatory processes. In this study we used an LPS-induced systemic inflammation model in rats to investigate the effect of blocking RAGE in serum, liver, cerebrospinal fluid (CSF) and brain (striatum, prefrontal cortex, ventral tegmental area and substantia nigra). Intraperitoneal injection of RAGE antibody (50¿µg/kg) was followed after 1¿h by a single LPS (5¿mg/kg) intraperitoneal injection. Twenty-four hours later, tissues were isolated for analysis. RAGE antibody reduced LPS-induced inflammatory effects in both serum and liver; the levels of proinflammatory cytokines (TNF-a, IL-1ß) were decreased and the phosphorylation/activation of RAGE downstream targets (ERK1/2, I¿B and p65) in liver were significantly attenuated. RAGE antibody prevented LPS-induced effects on TNF-a and IL-1ß in CSF. In striatum, RAGE antibody inhibited increases in IL-1ß, Iba-1, GFAP, phospho-ERK1/2 and phospho-tau (ser202), as well as the decrease in synaptophysin levels. These effects were caused by systemic RAGE inhibition, as RAGE antibody did not cross the blood-brain barrier. RAGE antibody also prevented striatal lipoperoxidation and activation of mitochondrial complex II. In conclusion, blockade of RAGE is able to inhibit inflammatory responses induced by LPS in serum, liver, CSF and brain.
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Nova |
2017 |
Kunzler A, Zeidán-Chuliá F, Gasparotto J, Girardi CS, Klafke K, Petiz LL, et al., 'Changes in Cell Cycle and Up-Regulation of Neuronal Markers During SH-SY5Y Neurodifferentiation by Retinoic Acid are Mediated by Reactive Species Production and Oxidative Stress', Molecular Neurobiology, 54 6903-6916 (2017) [C1]
Human neuroblastoma SH-SY5Y cells have been used as an in vitro model for neurodegenerative disorders such as Parkinson¿s disease and can be induced to a mature neuronal phenotype... [more]
Human neuroblastoma SH-SY5Y cells have been used as an in vitro model for neurodegenerative disorders such as Parkinson¿s disease and can be induced to a mature neuronal phenotype through retinoic acid (RA) differentiation. However, mechanisms of RA-induced differentiation remain unclear. Here, we investigate the role of reactive species (RS) on SH-SY5Y neuroblastoma cells under RA differentiation, using the antioxidant Trolox® as co-treatment. We found that RA treatment for 7¿days reduced the cell number and proliferative capacity and induced the expression of adult catecholaminergic/neuronal markers such as tyrosine hydroxylase (TH), ß-III tubulin, and enolase-2. Evaluation of intracellular RS production by DCFH oxidation assay and quantification of cell non-enzymatic antioxidant activity by TRAP demonstrated that RA increases RS production. Furthermore, mitochondrial NADH oxidation showed to be inhibited under differentiation with RA. Cells subjected to co-treatment with antioxidant Trolox® demonstrated a remaining proliferative capacity and a decrease in the pro-oxidant state and RS production. Besides, antioxidant treatment restores the mitochondrial NADH oxidation. Importantly, Trolox® co-treatment inhibited the appearance of morphological characteristics such as neurite extension and branching, and decreased the expression of TH, ß-III tubulin, and enolase-2 after a seven-day differentiation with RA, indicating that RS production is a necessary step in this process. Trolox® also inhibited the phosphorylation of Akt and ERK1/2, which are involved in differentiation and survival, respectively, of these cells. Altogether, these data indicate the presence of a redox-dependent mechanism in SH-SY5Y RA-differentiation process and can be a useful insight to improve understanding of neuronal differentiation signaling.
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Nova |
2016 |
James MH, Quinn RK, Ong LK, Levi EM, Smith DW, Dickson PW, Dayas CV, 'Rapamycin reduces motivated responding for cocaine and alters GluA1 expression in the ventral but not dorsal striatum', European Journal of Pharmacology, 784 147-154 (2016) [C1]
The mechanistic target of rapamycin complex 1 (mTORC1) regulates synaptic protein synthesis and therefore synaptic function and plasticity. A role for mTORC1 has recently been dem... [more]
The mechanistic target of rapamycin complex 1 (mTORC1) regulates synaptic protein synthesis and therefore synaptic function and plasticity. A role for mTORC1 has recently been demonstrated for addiction-related behaviors. For example, central or intra-accumbal injections of the mTORC1 inhibitor rapamycin attenuates several indices of cocaine-seeking including progressive ratio (PR) responding and reinstatement. These behavioral effects are associated with decreased mTORC1 activity and synaptic protein translation in the nucleus accumbens (NAC) and point to a possible therapeutic role for rapamycin in the treatment of addiction. Currently, it is unclear whether similar behavioral and biochemical effects can be achieved by administering rapamycin systemically, which represents a more clinically-appropriate route of administration. Here, we assessed the effects of repeated, systemic administration of rapamycin (10 mg/kg, i.p.) on PR responding for cocaine. We also assessed whether systemic rapamycin was associated with changes in measures of mTORC1 activity and GluA1 expression in the ventral and dorsal striatum. We report that systemic rapamycin treatment reduced PR breakpoints to levels comparable to intra-NAC rapamycin. Systemic rapamycin treatment also reduced phosphorylated p70S6K and GluA1 AMPARs within the NAC but not dorsal striatum. Thus, systemic administration of rapamycin is as effective at reducing drug seeking behavior and measures of mTORC1 activity compared to direct accumbal application and may therefore represent a possible therapeutic option in the treatment of addiction. Possible caveats of this treatment approach are discussed.
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Nova |
2016 |
Peres TV, Ong LK, Costa AP, Eyng H, Venske DKR, Colle D, et al., 'Tyrosine hydroxylase regulation in adult rat striatum following short-term neonatal exposure to manganese', Metallomics, 8 597-604 (2016) [C1]
Manganese (Mn) is an essential trace element required for a range of physiological processes, but Mn can also be neurotoxic especially during development. Excess levels of Mn accu... [more]
Manganese (Mn) is an essential trace element required for a range of physiological processes, but Mn can also be neurotoxic especially during development. Excess levels of Mn accumulate preferentially in the striatum and can induce a syndrome called manganism, characterized by an initial stage of psychiatric disorder followed by motor impairment. In the present study, we investigated the effects of Mn exposure on the developing dopaminergic system, specifically tyrosine hydroxylase (TH) protein and phosphorylation levels in the striatum of rats. Neonatal rats were exposed to Mn intraperitoneally (ip) from post-natal day 8 up to day 12 (PND8-12). Striatal tissue was analysed on PND14 or PND70, to detect either short-term or long-term effects induced by Mn exposure. There was a dose dependent increase in TH protein levels in the striatum at PND14, reaching significance at 20 mg kg-1 Mn, and this correlated with an increase in TH phosphorylation at serines 40, 31 and 19. However, in the striatum at PND70, a time by which Mn levels were no longer elevated, there was a dose dependent decrease in TH protein levels, reaching significance at 20 mg kg-1 Mn, and this correlated with TH phosphorylation at Ser40 and Ser19. There was however a significant increase in phosphorylation of TH at serine 31 at 20 mg kg-1 Mn, which did not correlate with TH protein levels. Taken together our findings suggest that neonatal Mn exposure can have both short-term and long-term effects on the regulation of TH in the striatal dopaminergic system.
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Nova |
2015 |
Quinn RK, Brown AL, Goldie BJ, Levi EM, Dickson PW, Smith DW, et al., 'Distinct miRNA expression in dorsal striatal subregions is associated with risk for addiction in rats', Translational Psychiatry, 5 (2015) [C1]
Recently, we published data using an animal model that allowed us to characterize animals into two groups, addiction vulnerable and addiction resilient, where we identified that a... [more]
Recently, we published data using an animal model that allowed us to characterize animals into two groups, addiction vulnerable and addiction resilient, where we identified that addiction/relapse vulnerability was associated with deficits in synaptic plasticityassociated gene expression in the dorsal striatum (DS). Notable was the strong reduction in expression for activity-regulated cytoskeleton-associated protein (Arc) considered a master regulator of synaptic plasticity. In the present study, we confirmed that Arc messenger RNA was significantly decreased in the DS, but importantly, we identified that this reduction was restricted to the dorsomedial (DMS) and not dorsolateral striatum (DLS). There is recent evidence of microRNA (miRNA)-associated posttranscriptional suppression of Arc and animal models of addiction have identified a key role for miRNA in the regulation of addiction-relevant genes. In further support of this link, we identified several differentially expressed miRNA with the potential to influence addiction-relevant plasticity genes, including Arc. A key study recently reported that miR-212 expression is protective against compulsive cocaine-seeking. Supporting this hypothesis, we found that miR-212 expression was significantly reduced in the DMS but not DLS of addiction-vulnerable animals. Together, our data provide strong evidence that miRNA promote ongoing plasticity deficits in the DS of addiction-vulnerable animals.
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Nova |
2014 |
James MH, Quinn RK, Ong LK, Levi EM, Charnley JL, Smith DW, et al., 'mTORC1 inhibition in the nucleus accumbens 'protects' against the expression of drug seeking and 'relapse' and is associated with reductions in GluA1 AMPAR and CAMKIIa levels.', Neuropsychopharmacology, 39 1694-1702 (2014) [C1]
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Nova |
2014 |
Briggs GD, Bulley J, Dickson PW, 'Catalytic domain surface residues mediating catecholamine inhibition in tyrosine hydroxylase', Journal of Biochemistry, 155 183-193 (2014) [C1]
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Nova |
2014 |
Ong LK, Guan L, Damanhuri H, Goodchild AK, Bobrovskaya L, Dickson PW, Dunkley PR, 'Neurobiological consequences of acute footshock stress: effects on tyrosine hydroxylase phosphorylation and activation in the rat brain and adrenal medulla', JOURNAL OF NEUROCHEMISTRY, 128 547-560 (2014) [C1]
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Nova |
2014 |
Stutz B, Lima da Conceicao FS, Santos LE, Cadilhe DV, Fleming RL, Acquarone M, et al., 'Murine dopaminergic Muller cells restore motor function in a model of Parkinson's disease', JOURNAL OF NEUROCHEMISTRY, 128 829-840 (2014) [C1]
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Nova |
2014 |
Hoffman A, Carpenter H, Kahl R, Watt LF, Dickson PW, Rostas JAP, et al., 'Dephosphorylation of CaMKII at T253 controls the metaphase-anaphase transition', Cellular Signalling, 26 748-756 (2014) [C1]
Calcium/calmodulin-stimulated protein kinase II (CaMKII) is a multi-functional serine/threonine protein kinase that controls a range of cellular functions, including proliferation... [more]
Calcium/calmodulin-stimulated protein kinase II (CaMKII) is a multi-functional serine/threonine protein kinase that controls a range of cellular functions, including proliferation. The biological properties of CaMKII are regulated by multi-site phosphorylation and targeting via interactions with specific proteins. To investigate the role specific CaMKII phosphorylation sites play in controlling cell proliferation and cell cycle progression, we examined phosphorylation of CaMKII at two sites (T253 and T286) at various stages of the cell cycle, and also examined the effects of overexpression of wild-type (WT), T286D phosphomimic, T253D phosphomimic and T253V phosphonull forms of CaMKIIa in MDA-MB-231 breast cancer and SHSY5Y neuroblastoma cells on cellular proliferation and cell cycle progression. We demonstrate herein that whilst there is no change in total CaMKII expression or T286 phosphorylation throughout the cell cycle, a marked dephosphorylation of CaMKII at T253 occurs during the G2 and/or M phases. Additionally, we show by molecular inhibition, as well as pharmacological activation, that protein phosphatase 2A (PP2A) is the phosphatase responsible for this dephosphorylation. Furthermore, we show that inducible overexpression of WT, T286D and T253V forms of CaMKIIa in MDA-MB-231 and SHSY5Y cells increases cellular proliferation, with no alteration in cell cycle profiles. By contrast, overexpression of a T253D phosphomimic form of CaMKIIa significantly decreases proliferation, and cells accumulate in mitosis, specifically in metaphase. Taken together, these results strongly suggest that the dephosphorylation of CaMKII at T253 is involved in controlling the cell cycle, specifically the metaphase-anaphase transition. © 2014 Elsevier Inc.
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Nova |
2014 |
Abdul Majeed ABB, Pearsall E, Carpenter H, Brzozowski J, Dickson PW, Rostas JAP, Skelding KA, 'CaMKII Kinase Activity, Targeting and Control of Cellular Functions: Effect of Single and Double Phosphorylation of CaMKIIa', Calcium Signaling, 1 36-51 (2014) [C1]
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Nova |
2013 |
Briggs G, Bulley J, Dunkley PR, Dickson PW, 'Structural Basis for Regulation of Tyrosine Hydroxlyase by the Catecholamines 8-9 (2013) [E3]
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2013 |
Skelding KA, Majeed ABA, Carpenter H, Dickson PW, Rostas JA, 'Can functional outcomes of CaMKII double phosphorylation be predicted from outcomes following single phosphorylation of CaMKII?', JOURNAL OF NEUROCHEMISTRY, 125 162-162 (2013) [E3]
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2013 |
Briggs GD, Nagy GM, Dickson PW, 'Mechanism of action of salsolinol on tyrosine hydroxylase', Neurochemistry International, 63 726-731 (2013) [C1]
Tyrosine hydroxylase (TH) is the first and rate-limiting enzyme in dopamine synthesis. Dopamine regulates TH as an end-product inhibitor through its binding to a high and low affi... [more]
Tyrosine hydroxylase (TH) is the first and rate-limiting enzyme in dopamine synthesis. Dopamine regulates TH as an end-product inhibitor through its binding to a high and low affinity site, the former being abolished by Ser40 phosphorylation only, and the latter able to bind and dissociate according to intracellular dopamine levels. Here, we have investigated TH inhibition by a dopamine metabolite found in dopaminergic brain regions, salsolinol (SAL). SAL is known to decrease dopamine in the nigrostriatal pathway and mediobasal hypothalamus, and to also decrease plasma catecholamines in rat stress models, however a target and mechanism for the effects of SAL have not been found. We found that SAL inhibits TH activity in the nanomolar range in vitro, by binding to both the high and low affinity dopamine binding sites. SAL produces the same level of inhibition as dopamine when TH is non-phosphorylated. However, it produces 3.7-fold greater inhibition of Ser40-phosphorylated TH compared to dopamine by competing more strongly with tetrahydrobiopterin, the cofactor of this enzymatic reaction. SAL's potent inhibition of phosphorylated TH would prevent TH from being fully activated to synthesise dopamine. Crown Copyright © 2013 Published by Elsevier Ltd. All rights reserved.
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Nova |
2013 |
Sominsky L, Fuller EA, Bondarenko E, Ong LK, Averell L, Nalivaiko E, et al., 'Functional Programming of the Autonomic Nervous System by Early Life Immune Exposure: Implications for Anxiety', PLOS ONE, 8 (2013) [C1]
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Nova |
2012 |
Skelding KA, Dickson PW, Verrills NM, Rostas JA, 'Progression through mitosis can be controlled by dephosphorylation of CaMKII at T253', JOURNAL OF NEUROCHEMISTRY, 123 31-31 (2012) [E3]
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2012 |
Rostas JA, Skelding KA, Fluechter L, Dickson PW, Spratt NJ, 'CaMKII is Differentially Regulated in Striatum and Cortex', JOURNAL OF NEUROCHEMISTRY, 123 63-63 (2012) [E3]
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Nova |
2012 |
Majeed ABA, Rostas JAP, Carpenter H, Dickson PW, Skelding KA, 'Multi-site phosphorylation of CaMKII regulates CaMKII function co-operatively', JOURNAL OF NEUROCHEMISTRY, 123 116-116 (2012) [E3]
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Nova |
2012 |
Skelding KA, Spratt NJ, Fluechter L, Dickson PW, Rostas JA, 'alpha CaMKII is differentially regulated in brain regions that exhibit differing sensitivities to ischemia and excitotoxicity', Journal of Cerebral Blood Flow and Metabolism, 32 2181-2192 (2012) [C1]
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2012 |
Ong LK, Sominsky L, Dickson PW, Hodgson DM, Dunkley PR, 'The sustained phase of Tyrosine hydroxylase activation in vivo', Neurochemical Research, 37 1938-1943 (2012) [C1]
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Nova |
2012 |
Damanhuri HA, Burke PGR, Ong LK, Bobrovskaya L, Dickson PW, Dunkley PR, Goodchild AK, 'Tyrosine hydroxylase phosphorylation in catecholaminergic brain regions: A marker of activation following acute hypotension and glucoprivation', Plos One, 7 1-19 (2012) [C1]
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Nova |
2011 |
Briggs GD, Gordon SL, Dickson PW, 'Mutational analysis of catecholamine binding in tyrosine hydroxylase', Biochemistry, 50 1545-1555 (2011) [C1]
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Nova |
2011 |
Aumann TD, Egan K, Lim J, Boon WC, Bye CR, Chua HK, et al., 'Neuronal activity regulates expression of tyrosine hydroxylase in adult mouse substantia nigra pars compacta neurons', Journal of Neurochemistry, 116 646-658 (2011) [C1]
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Nova |
2011 |
Ong LK, Guan L, Stutz B, Dickson PW, Dunkley PR, Bobrovskaya L, 'The effects of footshock and immobilization stress on tyrosine hydroxylase phosphorylation in the rat locus coeruleus and adrenal gland', Neuroscience, 192 20-27 (2011) [C1]
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Nova |
2011 |
Ong LK, Bobrovskaya L, Walker FR, Day TA, Dickson PW, Dunkley PR, 'The effect of social defeat on tyrosine hydroxylase phosphorylation in the rat brain and adrenal gland', Neurochemical Research, 36 27-33 (2011) [C1]
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Nova |
2010 |
Bobrovskaya L, Damanhuri HA, Ong LK, Schneider JJ, Dickson PW, Dunkley PR, Goodchild AK, 'Signal transduction pathways and tyrosine hydroxylase regulation in the adrenal medulla following glucoprivation: An in vivo analysis', Neurochemistry International, 57 162-167 (2010) [C1]
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Nova |
2010 |
Double KL, Halliday GM, Dunkley PR, Dickson PW, Gerlach M, Riederer P, 'Pigmentation in the human brain and risk of Parkinson's Disease', Annals of Neurology, 67 553-554 (2010) [C3]
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2010 |
Posser T, Dunkley PR, Dickson PW, Franco JL, 'Human neuroblastoma cells transfected with tyrosine hydroxylase gain increased resistance to methylmercury-induced cell death', Toxicology in Vitro, 24 1498-1503 (2010) [C1]
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Nova |
2010 |
Skelding KA, Suzuki T, Gordon SL, Xue J, Verrills NM, Dickson PW, Rostas JA, 'Regulation of CaMKII by phospho-Thr253 or phospho-Thr286 sensitive targeting alters cellular function', Cellular Signalling, 22 759-769 (2010) [C1]
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Nova |
2010 |
Franco JL, Posser T, Gordon SL, Bobrovskaya L, Schneider JJ, Farina M, et al., 'Expression of tyrosine hydroxylase increases the resistance of human neuroblastoma cells to oxidative insults', Toxicological Sciences, 113 150-157 (2010) [C1]
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Nova |
2009 |
Skelding KA, Liao X, Verrills NM, Fluechter L, Dickson PW, Rostas JA, 'CaMKII phosphorylation at T253 alters neuronal growth rates and morphology', Journal of Neurochemistry, 110, Suppl. 2 42 (2009) [E3]
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2009 |
Posser T, Franco JL, Bobrovskaya L, Leal RB, Dickson PW, Dunkley PR, 'Manganese induces sustained Ser40 phosphorylation and activation of tyrosine hydroxylase in PC12 cells', Journal of Neurochemistry, 110 848-856 (2009) [C1]
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Nova |
2009 |
Gordon SL, Bobrovskaya L, Dunkley PR, Dickson PW, 'Differential regulation of human tyrosine hydroxylase isoforms 1 and 2 in situ: Isoform 2 is not phosphorylated at Ser35', Biochimica et Biophysica Acta - Molecular Cell Research, 1793 1860-1867 (2009) [C1]
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Nova |
2009 |
Gordon SL, Webb JK, Shehadeh J, Dunkley PR, Dickson PW, 'The low affinity dopamine binding site on tyrosine hydroxylase: The role of the N-Terminus and in situ regulation of enzyme activity', Neurochemical Research, 34 1830-1837 (2009) [C1]
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Nova |
2009 |
Franco JL, Posser T, Dunkley PR, Dickson PW, Mattos JJ, Martins R, et al., 'Methylmercury neurotoxicity is associated with inhibition of the antioxidant enzyme glutathione peroxidase', Free Radical Biology and Medicine, 47 449-457 (2009) [C1]
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Nova |
2008 |
Gordon SL, Quinsey NS, Dunkley PR, Dickson PW, 'Tyrosine hydroxylase activity is regulated by two distinct dopamine-binding sites', Journal of Neurochemistry, 106 1614-1623 (2008) [C1]
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Nova |
2008 |
Skelding KA, Verrills NM, Fluechter L, Sim AT, Dickson PW, Rostas JA, 'Development of a novel method for the identification of CaMKII binding proteins', Journal of Neurochemistry, 106 51 (2008) [E3]
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2007 |
Bobrovskaya L, Gelain DP, Gilligan C, Dickson PW, Dunkley PR, 'PACAP stimulates the sustained phosphorylation of tyrosine hydroxylase at serine 40', Cellular Signalling, 19 1141-1149 (2007) [C1]
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2007 |
Bobrovskaya L, Gilligan C, Bolster EK, Flaherty JJ, Dickson PW, Dunkley PR, 'Sustained phosphorylation of tyrosine hydroxylase at serine 40: a novel mechanism for maintenance of catecholamine synthesis', Journal of Neurochemistry, 100 479-489 (2007) [C1]
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2007 |
Gelain DP, Moreira JCF, Bevilaqua LRM, Dickson PW, Dunkley PR, 'Retinol activates tyrosine hydroxylase acutely by increasing the phosphorylation of serine40 and then serine31 in bovine adrenal chromaffin cells', Journal of Neurochemistry, 103 2369-2379 (2007) [C1]
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2006 |
Migues PV, Lehmann IT, Fluechter L, Cammarota MP, Gurd JW, Sim AT, et al., 'Phosphorylation of CaMKII at Thr253 occurs in vivo and enhances binding to isolated postsynaptic densities', Journal of Neurochemistry, 98 289-299 (2006) [C1]
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Nova |
2006 |
Lehmann IT, Bobrovskaya L, Gordon SL, Dunkley PR, Dickson PW, 'Differential regulation of the human tyrosine hydroxylase isoforms via hierarchical phosphorylation', Journal of Biological Chemistry, 281 17644-17651 (2006) [C1]
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Nova |
2005 |
Graham ME, Dickson PW, Dunkley PR, Von Nagy-Felsobuki EI, 'Characterisation of tryptic peptides of phosphorylated tyrosine hydroxylase by high-pressure liquid chromatography electrospray ionisation mass spectrometry', Journal of Electron Spectroscopy and Related Phenomena, 142 271-276 (2005) [C1]
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Nova |
2004 |
Dunkley PR, Bobrovskaya L, Graham ME, Von Nagy-Felsobuki EI, Dickson PW, 'Tyrosine hydroxylase phosphorylation: regulation and consequences', Journal of Neurochemistry, 91 1025-1043 (2004) [C1]
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Nova |
2003 |
Bevilaqua L, Cammarota MP, Dickson PW, Sim AT, Dunkley PR, 'Role of protein phosphatase 2C from bovine adrenal chromaffin cells in the dephosphorylation of phospho-serine 40 tyrosine hydroxylase', Journal of Neurochemistry, 85 1368-1373 (2003) [C1]
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2001 |
Bevilaqua L, Graham ME, Dunkley PR, Von Nagy-Felsobuki EI, Dickson PW, 'Phosphorylation of Ser19 Alters the Conformation of Tyrosine Hydroxylase to Increase the Rate of Phosphorylation of Ser40*', The Journal of Biological Chemistry, 276 No. 44 40411-40416 (2001) [C1]
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Nova |
2001 |
Bevilaqua L, Graham ME, Von Nagy-Felsobuki EI, Dunkley PR, Dickson PW, 'Effect of phosphorylation on tyrosine hydroxylase shape', Journal of Neurochemistry, 78 Supt. 1 143 (2001) [C3]
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2001 |
Graham ME, Bevilaqua L, Dunkley PR, Von Nagy-Felsobuki EI, Dickson PW, 'The Kinetics of CAMKII Phosphorylation of Dopamine Bound-Tyrosine Hydroxylase Determined by Electrospray Mass Spectrometry', ComBio 2001, 0 (2001) [C3]
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2000 |
Graham ME, Dickson PW, Dunkley PR, Von Nagy-Felsobuki EI, 'Determination of Phosphorylation Levels of Tyrosine Hydroxylase by Electrospray Mass Spectrometry', Analytical Biochemistry, 280 1-7 (2000) [C1]
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1999 |
Dickson PW, Wong Z, Harrap S, Abramson M, Walters E, 'Mutational analysis of the high affinity immunoglobulin E receptor Beta subunit gene in asthma', Thorax (The Journal of the British Thoracic Society), 54 409-412 (1999) [C1]
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1998 |
Quinsey NS, Luong AQ, Dickson PW, 'Mutational analysis of substrate inhibition in tyrosine hydroxylase', Journal of Neurochemistry, 71 2132-2138 (1998) [C1]
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1998 |
Graham ME, Dickson PW, Dunkley PR, Von Nagy-Felsobuki EI, 'Characterisation of the phosphorylation of rat tyrosine hydroxylase using electrospray mass spectrometry', Rapid Communications in Mass Spectrometry, 12 746-748 (1998) [C1]
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1998 |
Graham ME, Dickson P, Dunkley P, Von Nagy-Felsobuki EI, 'Characterization of the Phosphorylation of Rat Tyrosine Hydroxylase using Electrospray Mass Spectrometry', Rapid Communications in Mass Spectrometry, 12 746-748 (1998) [C1]
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1997 |
Kamitani A, Wong ZYH, Dickson P, Van Herwerden L, Raven J, Forbes AB, et al., 'Absence of genetic linkage of chromosome 5q31 with asthma and atopy in the general population', Thorax, 52 816-817 (1997)
Background - Clinical asthma is associated with increased serum total immunoglobulin E (IgE), atopy (skin prick test positivity to common aeroallergens), and bronchial hyperreacti... [more]
Background - Clinical asthma is associated with increased serum total immunoglobulin E (IgE), atopy (skin prick test positivity to common aeroallergens), and bronchial hyperreactivity (BHR) to non-specific stimuli (positive methacholine challenge test). A region on chromosome 5q31-33 has been linked with increased total serum IgE and BHR. A study of the genetic linkage of this region with clinical asthma and atopy was therefore undertaken. Methods - A polymorphic microsatellite marker in chromosome 5q31 (D5S399) was studied in 119 sibling pairs recruited from the general population who shared asthma, atopy, and/or BHR. Based on our population distribution of 13 different alleles, it was expected that by chance alone sibling pairs would share on average 1.24 alleles and that a significant excess would indicate genetic linkage. Results - No evidence of linkage was found in 45 siblings concordant for asthma (shared alleles = 1.09, p = 0.95), in 103 sibling pairs with atopy (shared alleles = 1.18, p = 0.82), in 51 sibling pairs with BHR (shared alleles = 1.22, p = 0.62), or in 68 sibling pairs who shared atopy in the absence of BHR (shared alleles = 1.22, p = 0.61). A slight non-significant excess of shared alleles (1.44, p = 0.11) was observed in siblings who shared BHR without atopy. Conclusions - No evidence of genetic linkage of chromosome 5q31 with either clinical asthma or atopy was therefore detected in the population studied. Linkage between chromosome 5q and BHR needs further investigation.
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1996 |
Quinsey NS, Lenaghan CM, Dickson PW, 'Identification of Gln
Rat tyrosine hydroxylase was expressed in Escherichia coli. High-level expression was obtained after incubation at 27°C for 18 h. The smallest fragment of tyrosine hydroxylase tha... [more]
Rat tyrosine hydroxylase was expressed in Escherichia coli. High-level expression was obtained after incubation at 27°C for 18 h. The smallest fragment of tyrosine hydroxylase that gave a soluble active molecule was from Leu188 to Phe456. This fragment corresponds directly to the section of phenylalanine hydroxylase that had previously been shown to be this enzyme's catalytic core region. It has been shown that Glu286 plays a critical role in pterin function in phenylalanine hydroxylase. The corresponding residue in tyrosine hydroxylase (Glu332) has no significant role in pterin function. Substitution of a leucine for a proline at position 327 in tyrosine hydroxylase produces a molecule with a Km for tetrahydrobiopterin 20-fold higher than that of the wild-type molecule, whereas the same substitution at the corresponding residue in phenylalanine hydroxylase (Pro281) has no effect on the kinetic constant for the cofactor. This suggests that corresponding residues in phenylalanine hydroxylase and tyrosine hydroxylase can have different roles in pterin function. Substitution of a leucine for a proline at position 281 in phenylalanine hydroxylase increases the Km for phenylalanine >20-fold over that of the wild-type. Substitution of leucine or alanine for Pro327 or a glutamic acid for Gln313 in tyrosine hydroxylase eliminates the substrate inhibition shown by wild-type tyrosine hydroxylase.
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1996 |
Dickson PW, Quinsey NS, 'Analysis of substrate inhibition in tyrosine hydroxylase', FASEB Journal, 10 (1996)
Tyrosine hydroxylase (TYRH) belongs to a family of aromatic amino acid hydroxylases which also includes phenylalanine hydroxylase (PAH) and tryptophan hydroxylase. The three enzym... [more]
Tyrosine hydroxylase (TYRH) belongs to a family of aromatic amino acid hydroxylases which also includes phenylalanine hydroxylase (PAH) and tryptophan hydroxylase. The three enzymes are functionally related and have a high similarity in amino acid sequence of their catalytic domains. TYRH and PAH have common boundaries in their catalytic domains (1,2). We have identified residues involved in co-factor and substrate function in PAH (1,2). We have also delineated residues that are involved in substrate inhibition in TYRH (2). Analysis of deletion mutants of TYRH has identified mutants which show no substrate inhibition but retain high specific activity. This suggests that the tyrosine inhibition site in TYRH maybe functionally distinct from the tyrosine catalytic site. (1) Dickson, P.W., Jennings, I.G., and Cotton, R.G.H. (1994) J. Biol. Chem. 269 ,20369-20375. (2) Quinsey, N.S., Lenaghan, C.M.. and Dickson, P.W. (1996) J. Neurochem. 66 ,908-914.
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1994 |
Dickson PW, Jennings IG, Cotton RGH, 'Delineation of the catalytic core of phenylalanine hydroxylase and identification of glutamate 286 as a critical residue for pterin function', Journal of Biological Chemistry, 269 20369-20375 (1994)
Rat phenylalanine hydroxylase was expressed in Escherichia coli. High level expression was achieved when the transformed E. coli were incubated at 27 °C for 24 h. A series of trun... [more]
Rat phenylalanine hydroxylase was expressed in Escherichia coli. High level expression was achieved when the transformed E. coli were incubated at 27 °C for 24 h. A series of truncated fragments were expressed. The smallest fragment that gave an active soluble protein was from Leu142 to Phe410. This fragment corresponds closely to the region where there is highest homology between the three aromatic amino acid hydroxylases. The circular dichroism spectra of the phenylalanine hydroxylase catalytic core suggested that it contains around 50% a-helix. The core fragment is monomeric in dilute solutions but self-associates at higher concentrations. The E. coli expression system was used to generate a number of mutations in phenylalanine hydroxylase from position 264 to 290. This region had been previously shown to be important for pterin binding. Characterization of the mutant phenylalanine hydroxylase molecules identified Glu286 as an amino acid critical for pterin function in phenylalanine hydroxylase.
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1989 |
COLE T, DICKSON PW, ESNARD F, AVERILL S, RISBRIDGER GP, GAUTHIER F, SCHREIBER G, 'The cDNA structure and expression analysis of the genes for the cysteine proteinase inhibitor cystatin C and for ß
Tissue patterns of gene expression were analyzed by measuring mRNA levels and incorporation of radioactive amino acids for cystatin C and ß2-microglobulin, the two extracellular p... [more]
Tissue patterns of gene expression were analyzed by measuring mRNA levels and incorporation of radioactive amino acids for cystatin C and ß2-microglobulin, the two extracellular proteins in the brain with the highest ratio of concentration in cerebrospinal fluid over that in blood plasma. The primary structure of rat cystatin C mRNA from choroid plexus was determined by nucleotide sequencing of cloned cDNA and the tissue patterns of gene expression were analysed by RNA blot analysis and in situ hybridization. Cystatin C was found to be composed of 120 amino acids and to contain a potential site for N-linked glycosylation. The tissue with the highest cystatin C mRNA level was the choroid plexus of the brain. Cystatin C mRNA was also detected in lower levels in other areas of the brain, testis, epididymis, seminal vesicles, prostate, ovary, submandibular gland, and, in trace amounts, in liver. Choroid plexus pieces in culture secreted radioactive cystatin C when incubated with radioactive leucine. Rat ß2-microglobulin cDNA was cloned and identified by nucleotide sequencing and comparison of the obtained sequence with that of mouse and human ß2-microglobulin cDNA. Tissue levels of ß2-microglobulin mRNA in the rat were measured by hybridization to rat ß2-microglobulin cDNA. The highest levels of ß2-microglobulin mRNA were observed in liver and choroid plexus. Other parts of the brain and testis contained lower levels of ß2-microglobulin mRNA. Copyright © 1989, Wiley Blackwell. All rights reserved
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1989 |
SCHREIBER G, TSYKIN A, ALDRED AR, THOMAS T, FUNG W, DICKSON PW, et al., 'The Acute Phase Response in the Rodent', Annals of the New York Academy of Sciences, 557 61-86 (1989)
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1988 |
Wai-Ping Fung, Thomas T, Dickson PW, Aldred AR, Milland J, Dziadek M, et al., 'Structure and expression of the rat transthyretin (prealbumin) gene', Journal of Biological Chemistry, 263 480-488 (1988)
The rat transthyretin gene, 7.3 kilobase pairs (kb) long, with 14.5 kb of 5' flanking and 12.2 kb of 3' flanking region was cloned and characterized. The gene contained ... [more]
The rat transthyretin gene, 7.3 kilobase pairs (kb) long, with 14.5 kb of 5' flanking and 12.2 kb of 3' flanking region was cloned and characterized. The gene contained four exons. A 'TATA box' sequence (5'-TATATAA-3') and a 'CAAT box' sequence (5'-GTCAAT-3') were located 23 and 95 nucleotides upstream, respectively, from the major transcription start site. Nucleotides -51 to -189 were highly conserved (93% homology between rats and humans, 97% homology between rats and mice). Tandem repeats of sequences of 5'-AC-3' and 5'-ACACATGC-3' in the 5' flanking region, of 5'-GAAA-3' in the first intron, and of 5'-GT-3' in the third intron of the gene were observed. Using specific cDNA probes, tissue specificity and regulation of transthyretin mRNA biosynthesis durig embyrogenesis were analyzed. Transthyretin expression occurred first in the yolk sac, then decreased when expression increased in fetal liver. Presumptive choroid plexus cells in the inner lining of the neural tube expressed transthyretin early in gestation (11 days before birth) with a maximum immediately preceding the spurt of brain growth around birth. Partial hepatectomy of adult rats induced both an acute phase response and regenerative growth in liver. The decrease in transcription of the transthyretin gene in liver, which is characteristic for the acute phase response, was overridden by stimulating of gene expression after partial hepatectomy. This stimulation also affected transthyretin expression in choroid plexus.
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1987 |
Aldred AR, Dickson PW, Marley PD, Schreiber G, 'Distribution of transferrin synthesis in brain and other tissues in the rat.', Journal of Biological Chemistry, 262 5293-5297 (1987)
Levels of transferrin mRNA were measured by hybridization to transferrin cDNA in extracts from various areas of rat brain and other tissues. The highest concentrations of transfer... [more]
Levels of transferrin mRNA were measured by hybridization to transferrin cDNA in extracts from various areas of rat brain and other tissues. The highest concentrations of transferrin mRNA were found in the liver and the choroid plexus of the lateral and third ventricles. Lower concentrations were observed in the medulla and thalamus, choroid plexus of the fourth ventricle, cortex, hypothalamus, cerebellum, pituitary, testis, placenta, stomach, spleen, kidney, muscle, and heart. Yolk sac, small intestine, and adrenal glands did not contain detectable transferrin mRNA levels. The size of transferrin mRNA was the same in liver, brain, and testis. Upon incubation of choroid plexus pieces with [14C]leucine in vitro, about 4% of the radioactive protein secreted into the medium was found to be transferrin. Together with previous data (Dickson, P.W., Howlett, G.J., and Schreiber, G. (1985) J. Biol. Chem. 260, 8214-8219; Dickson, P.W., Aldred, A.R., Marley, P.D., Bannister, D., and Schreiber (1986) J. Biol. Chem. 261, 3475-3478) the obtained data suggest that the choroid plexus plays a role in maintenance of homeostasis in the microenvironment of the central nervous system by synthesizing and secreting plasma proteins.
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1987 |
Dickson PW, Aldred AR, Menting JG, Marley PD, Sawyer WH, Schreiber G, 'Thyroxine transport in choroid plexus.', The Journal of biological chemistry, 262 13907-13915 (1987)
The role of the choroid plexus in thyroid hormone transport between body and brain, suggested by strong synthesis and secretion of transthyretin in this tissue, was investigated i... [more]
The role of the choroid plexus in thyroid hormone transport between body and brain, suggested by strong synthesis and secretion of transthyretin in this tissue, was investigated in in vitro and in vivo systems. Rat choroid plexus pieces incubated in vitro were found to accumulate thyroid hormones from surrounding medium in a non-saturable process. At equilibrium, the ratio of thyroid hormone concentration in choroid plexus pieces to that in medium decreased upon increasing the concentration of transthyretin in the medium. Fluorescence quenching of fluorophores located at different depths in liposome membranes showed maximal hormone accumulation in the middle of the phospholipid bilayer. Partition coefficients of thyroxine and triiodothyronine between lipid and aqueous phase were about 20,000. After intravenous injection of 125I-labeled thyroid hormones, choroid plexus and parts of the brain steadily accumulated 125I-thyroxine, but not [125I]triiodothyronine, for many hours. The accumulation of 125I-thyroxine in choroid plexus preceded that in brain. The amount of 125I-thyroxine in non-brain tissues and the [125I]triiodothyronine content of all tissues decreased steadily beginning immediately after injection. A model is proposed for thyroxine transport from the bloodstream into cerebrospinal fluid based on partitioning of thyroxine between choroid plexus and surrounding fluids and binding of thyroxine to transthyretin newly synthesized and secreted by choroid plexus.
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1987 |
Dickson PW, Bannister D, Schreiber G, 'Minor burns lead to major changes in synthesis rates of plasma proteins in the liver', Journal of Trauma - Injury, Infection and Critical Care, 27 283-286 (1987)
The effect of minor burns on the rates of synthesis of plasma proteins in the liver was studied in white Buffalo rats. Burns of second to third degree, covering 0.8% of total body... [more]
The effect of minor burns on the rates of synthesis of plasma proteins in the liver was studied in white Buffalo rats. Burns of second to third degree, covering 0.8% of total body surface, were produced by short application of a hot piece of metal to the skin under ether anesthesia. Levels of mRNA in extracts from liver removed after 24 hr were measured by hybridization to radioactively labeled specific cDNA probes. The level of mRNA for major acute phase ar-protein (also called cysteine proteinase inhibitor or Tl-kininogen) increased 20-fold, that of fibrinogen mRNA 8-fold, and that of a,-acid glycoprotein mRNA about 9-fold. The levels of albumin mRNA and transthyretin mRNA (also called prealbumin) decreased to about 80% of normal and the level of transferrin mRNA did not change significantly. Thus, although the percentage of burnt skin was only very small, a typical acute phase response of plasma protein synthesis in liver was observed. © 1987 by The Williams & Wilkins Co.
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1986 |
Dickson PW, Aldred AR, Marley PD, Bannister D, Schreiber G, 'Rat choroid plexus specializes in the synthesis and the secretion of transthyretin (Prealbumin). Regulation of transthyretin synthesis in choroid plexus is independent from that in liver', Journal of Biological Chemistry, 261 3475-3478 (1986)
Synthesis of total protein and of transthyretin in rat choroid plexus was studied by measuring the incorporation of radioactive leucine into proteins in choroid plexus tissue incu... [more]
Synthesis of total protein and of transthyretin in rat choroid plexus was studied by measuring the incorporation of radioactive leucine into proteins in choroid plexus tissue incubated in vitro. About 20% of the protein newly synthesized in choroid plexus and about 50% of the newly synthesized protein secreted into the medium was transthyretin. Evidently, the choroid plexus is very active in the biosynthesis of this carrier protein for thyroid hormones and could be an important link in the chemical communication between the body and the central nervous system. Acute inflammation, which leads to a profound rearrangement of the pattern of plasma protein synthesis rates in the liver, produced distinct changes in the levels for plasma protein mRNAs in the liver. The levels of the mRNAs for a1-acid glycoprotein and major acute phase a1-protein increased more than 30-fold, those for transthyretin and albumin decreased to 27 and 57% of normal, respectively. The pattern of the observed changes in the levels of mRNAs for plasma proteins in the liver was independent of whether the acute inflammation was produced by subcutaneous injection of turpentine or intraperitoneal injection of a suspension of talcum. However, levels of transthyretin mRNAs in choroid plexus were affected only very slightly, or not al all. Apparently, transthyretin synthesis in liver and choroid plexus is regulated independently during the acute phase response. No mRNA was detected in choroid plexus for albumin, a1-acid glycoprotein, and major acute phase a1-protein under any conditions.
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1986 |
Stauder AJ, Dickson PW, Aldred AR, Schreiber G, Mendelsohn FA, Hudson P, 'Synthesis of transthyretin (pre-albumin) mRNA in choroid plexus epithelial cells, localized by in situ hybridization in rat brain', Journal of Histochemistry and Cytochemistry, 34 949-952 (1986)
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1986 |
Dickson PW, Schreiber G, 'High levels of messenger RNA for transthyretin (prealbumin) in human choroid plexus', Neuroscience Letters, 66 311-315 (1986)
We have investigated the expression of the gene for transthyretin (prealbumin) in the human choroid plexus. RNA was isolated from the human choroid plexus, fractionated by electro... [more]
We have investigated the expression of the gene for transthyretin (prealbumin) in the human choroid plexus. RNA was isolated from the human choroid plexus, fractionated by electrophoresis in agarose gel and transferred onto a nitrocellulose filter membrane. Transthyretin messenger RNA (mRNA) was identified by hybridization to radioactive complementary DNA for rat transthyretin. The level of transthyretin mRNA in the human choroid plexus was found to be at least 40 times higher than in human liver, suggesting very active synthesis of transthyretin in the choroid plexus. © 1986.
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1986 |
Schreiber G, Aldred AR, Thomas T, Birch HE, Dickson PW, Guo-Fen T, et al., 'Levels of messenger ribonucleic acids for plasma proteins in rat liver during acute experimental inflammation', Inflammation, 10 59-66 (1986)
The levels of mRNA for plasma proteins and for metallothionein in rat liver during the acute-phase response were studied by hybridization to specific cDNA probes. The mRNA for a2-... [more]
The levels of mRNA for plasma proteins and for metallothionein in rat liver during the acute-phase response were studied by hybridization to specific cDNA probes. The mRNA for a2-macroglobulin, the ß-chain of fibrinogen, a1,-acid glycoprotein (so-called acute-phase reactants) reached a maximum level between 18 and 36 h after inducing an acute inflammation. The level of mRNA for metallothionein-I peaked earlier, after 12 h. The mRNA for transferrin showed a delayed increase with a broad maximum for its relative level after 36-60 h. The mRNA levels for albumin and a2u-globulin (so-called negative acute-phase reactants) decreased, reaching a minimum of 25 % of the normal level after 36 h (albumin) and after 72 h (a2u-globulin). The ratios of the rates of incorporation of leucine into the proteins over the levels of their mRNA in liver changed only a little, indicating that the rates of synthesis of plasma proteins in the liver are regulated at the mRNA level during the acute-phase response to inflammation. © 1986 Plenum Publishing Corporation.
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1985 |
Dickson PW, Aldred AR, Marley PD, Guo-Fen T, Howlett GJ, Schreiber G, 'High prealbumin and transferrin mRNA levels in the choroid plexus of rat brain', Biochemical and Biophysical Research Communications, 127 890-895 (1985)
Expression of plasma protein genes in various parts of the rat brain was studied by hybridizing radioactive cDNA to RNA in cytoplasmic extracts. No mRNA could be detected in brain... [more]
Expression of plasma protein genes in various parts of the rat brain was studied by hybridizing radioactive cDNA to RNA in cytoplasmic extracts. No mRNA could be detected in brain for the ß subunit of fibrinogen, major acute phase a1-protein, a1-acid glycoprotein and albumin. However, per g tissue, the choroid plexus contained at least 100 times larger amounts of prealbumin mRNA than the liver and about the same amount of transferrin mRNA as liver. No prealbumin mRNA was found in other areas of the brain. The results obtained suggest very active synthesis of prealbumin in choroid plexus, which would be an important link in the transport of thyroid hormones from the blood to the brain via the cerebrospinal fluid. © 1985 Academic Press, Inc.
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1985 |
Dickson PW, Howlett GJ, Schreiber G, 'Rat transthyretin (prealbumin). Molecular cloning, nucleotide sequence, and gene expression in liver and brain', Journal of Biological Chemistry, 260 8214-8219 (1985)
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1982 |
Howlett GJ, Dickson PW, Birch H, Schreiber G, 'Studies on
The molecular weights of a number of 125I-labeled plasma proteins have been determined from an analysis of their sedimentation equilibrium behavior in an air-driven ultracentrifug... [more]
The molecular weights of a number of 125I-labeled plasma proteins have been determined from an analysis of their sedimentation equilibrium behavior in an air-driven ultracentrifuge. The values obtained agree well with results obtained by other methods. Molecular weights obtained for 125I-labeled bovine serum albumin and the rat serum proteins albumin, a1-acid glycoprotein, and major acute-phase a1-protein were unaffected by the addition of 7% rat plasma. Direct evidence for protein-protein interactions was obtained for mixtures of 125I-labeled rat a1-acid glycoprotein and the plant lectin concanavalin A and for mixtures of 125I-labeled protein A from Staphylococcus aureus and 7% rat plasma. Interactions of a different type were observed when the sedimentation equilibrium profiles of 125I-labeled proteins were determined in concentrated solutions of other proteins. Under these conditions the effects of molecular exclusion or nonideality became significant and low estimates were obtained for the molecular weights of the labeled proteins. Analysis of the data obtained for 125I-labeled bovine serum albumin in concentrated solutions of bovine serum albumin (20-80 mg/ ml) yielded nonideality coefficients in good agreement with literature values. Analysis of the behavior of 125I-labeled rat serum albumin, transferrin, and a1-acid glycoprotein yielded nonideality coefficients and hence activities of these proteins in undiluted rat plasma. © 1982.
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1982 |
Howlett GJ, Birch H, Dickson PW, Schreiber G, 'Determination of the molecular weight of detergent-solubilized enzymes by sedimentation equilibrium in an air-driven ultracentrifuge', Biochemical and Biophysical Research Communications, 105 895-901 (1982)
Detergent solubilization of ¿-glutamyl transpeptidase was deduced from measuring sedimentation equilibrium behaviour in an air-driven ultra-centrifuge. Sequential fractionation of... [more]
Detergent solubilization of ¿-glutamyl transpeptidase was deduced from measuring sedimentation equilibrium behaviour in an air-driven ultra-centrifuge. Sequential fractionation of the tube contents and analysis of the radial concentration dependence permits direct determination of molecular weight. Studies using D2O and H2O indicate that the Triton X-100 solubilized enzyme has a molecular weight of approximately 175,000 and contains 55% bound detergent. The glycoprotein nature of the enzyme is demonstrated by its interaction with concanavalin A. © 1982.
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1982 |
DICKSON PW, HOWLETT GJ, SCHREIBER G, 'Metabolism of Prealbumin in Rats and Changes Induced by Acute Inflammation', European Journal of Biochemistry, 129 289-293 (1982)
Prealbumin was purified from rat plasma by chromatography on Blue Sepharose CL-6B, followed by chromatography on concanavalin-A¿Sepharose and preparative electrophoresis in polyac... [more]
Prealbumin was purified from rat plasma by chromatography on Blue Sepharose CL-6B, followed by chromatography on concanavalin-A¿Sepharose and preparative electrophoresis in polyacrylamide gel. The overall recovery was 20%. The purified prealbumin was homogeneous upon electrophoresis in detergent containing polyacrylamide gel and was used to raise a monospecific anti-serum in rabbits. During perfusion of rat liver, [14C]-leucine was incorporated into prealbumin secreted into the perfusion medium, suggesting that the liver was synthesizing prealbumin. The ratio of the rate of incorporation of leucine into prealbumin to that into total protein was 1.5%. 125I-prealbumin had a half-life of 29 h in the bloodstream of healthy Buffalo rats on a diet containing 20% protein. Whole body homogenates from healthy rats contained 6.2 mg prealbumin/100 g body weight. The rate of synthesis of prealbumin, calculated from half-life and total body pool, was 3.6 mg prealbumin × (100 g body weight)¿1× day¿1. Two days after induction of inflammation by a subcutaneous injection of turpentine, both the concentration of prealbumin in the plasma and the amount of prealbumin in the whole body homogenates decreased to a minimum of about one third of normal. The relative rate of degradation of 125I-prealbumin did not change during inflammation. The rate of synthesis of prealbumin decreased considerably, or even ceased, during acute inflammation. Copyright © 1982, Wiley Blackwell. All rights reserved
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