The Experts below are selected from a list of 4983 Experts worldwide ranked by ideXlab platform
Hon Cheung Lee - One of the best experts on this subject based on the ideXlab platform.
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the transferrin receptor cd71 regulates type ii cd38 revealing tight topological compartmentalization of intracellular Cyclic adp ribose production
Journal of Biological Chemistry, 2019Co-Authors: Qi Wen Deng, Hon Cheung Lee, Jingzi Zhang, Lei Fang, Yong Juan ZhaoAbstract:The CD38 molecule (CD38) catalyzes biogenesis of the calcium-mobilizing messenger Cyclic ADP-ribose (cADPR). CD38 has dual membrane orientations, and type III CD38, with its catalytic domain facing the cytosol, has low abundance but is efficient in cyclizing cytosolic NAD to produce cADPR. The role of cell surface type II CD38 in cellular cADPR production is unknown. Here we modulated type II CD38 expression and assessed the effects of this modulation on cADPR levels. We developed a photoactivatable cross-linking probe based on a CD38 nanobody, and, combining it with MS analysis, we discovered that cell surface CD38 interacts with CD71. CD71 knockdown increased CD38 levels, and CD38 knockout reciprocally increased CD71, and both could be cocapped and coimmunoprecipitated. We constructed a chimera comprising the N-terminal segment of CD71 and a CD38 nanobody to mimic CD71's ligand property. Overexpression of this chimera induced a dramatically large decrease in CD38 via lysosomes. Remarkably, cellular cADPR levels did not decrease correspondingly. Bafilomycin-mediated blockade of lysosomal degradation greatly elevated active type II CD38 by trapping it in the lysosomes but also did not increase cADPR levels. Retention of type II CD38 in the endoplasmic reticulum (ER) by expressing an ER construct that prevented its transport to the cell surface likewise did not change cADPR levels. These results provide first and direct evidence that cADPR biogenesis occurs in the cytosol and is catalyzed mainly by type III CD38 and that type II CD38, compartmentalized in the ER or lysosomes or on the cell surface, contributes only minimally to cADPR biogenesis.
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determination of adp ribosyl cyclase activity Cyclic adp ribose and nicotinic acid adenine dinucleotide phosphate in tissue extracts
Methods of Molecular Biology, 2013Co-Authors: Richard Graeff, Hon Cheung LeeAbstract:Abstract Cyclic ADP-ribose (cADPR) is a novel second messenger that releases calcium from intracellular stores. Although first shown to release calcium in the sea urchin egg, cADPR has been shown since to be active in a variety of cells and tissues, from plant to human. cADPR stimulates calcium release via ryanodine receptors although the mechanism is still not completely understood. cADPR is produced enzymatically from NAD by ADP-ribosyl cyclases; several of these proteins have been identified including one isolated from Aplysia californica, two types found in mammals (CD38 and CD157), and three forms in sea urchin. A cyclase activity has been measured in extracts from Arabidopsis thaliana although the protein is still unidentified. Nicotinic acid adenine dinucleotide phosphate (NAADP) is another novel messenger that releases calcium from internal stores and is produced by these same enzymes by an exchange reaction. NAADP targets lysosomal stores whereas cADPR releases calcium from the endoplasmic reticulum. Due to their importance in cell signaling, cADPR and NAADP have been the focus of numerous investigations over the last 25 years. This chapter describes several assay methods for the measurements of cADPR and NAADP concentration and cyclase activity in extracts from cells.
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Cyclic adp ribose and nicotinic acid adenine dinucleotide phosphate naadp as messengers for calcium mobilization
Journal of Biological Chemistry, 2012Co-Authors: Hon Cheung LeeAbstract:Cyclic ADP-ribose and nicotinic acid adenine dinucleotide phosphate were discovered >2 decades ago. That they are second messengers for mobilizing Ca2+ stores has since been firmly established. Separate stores and distinct Ca2+ channels are targeted, with Cyclic ADP-ribose acting on the ryanodine receptors in the endoplasmic reticulum, whereas nicotinic acid adenine dinucleotide phosphate mobilizes the endolysosomes via the two-pore channels. Despite the structural and functional differences, both messengers are synthesized by a ubiquitous enzyme, CD38, whose crystal structure and catalytic mechanism have now been well elucidated. How this novel signaling enzyme is regulated remains largely unknown and is the focus of this minireview.
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Cyclic adp ribose links metabolism to multiple fission in the dinoflagellate crypthecodinium cohnii
Cell Calcium, 2009Co-Authors: Connie M C Lam, Hon Cheung Lee, Patrick K K Yeung, Joseph T Y WongAbstract:Abstract Cellular metabolism is required for cell proliferation. However, the way in which metabolic signals are conveyed to cell cycle decisions is unclear. Cyclic ADP-ribose (cADPR), the NAD + metabolite, mobilizes calcium from calcium stores in many cells. We found that dinoflagellate cells with higher metabolic rate underwent multiple fission (MF), a division mode in which cells can exceed twice their sizes at G1. A temperature shift-down experiment suggested that MF involves a commitment point at late G1. In fast-growing cells, cADPR level peaked in G 1 and increased with increasing concentrations of glucose in the medium. Addition of glycolytic poison iodoacetate inhibited cell growth, reduced cADPR levels as well as the commitment of cell cycles in fast-growing cells. Commitment of MF cell cycles was induced by a cell permeant cADPR agonist, but blocked by a specific antagonist of cADPR-induced Ca 2+ release. Our results establish cADPR as a link between cellular metabolism and cell cycle control.
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Mechanism of cyclizing NAD to Cyclic ADP-ribose by ADP-ribosyl cyclase and CD38
Journal of Biological Chemistry, 2009Co-Authors: Richard Graeff, Quan Hao, Masayo Kotaka, Norman Oppenheimer, Irina A Kriksunov, Qun Liu, Hon Cheung LeeAbstract:Mammalian CD38 and its Aplysia homolog, ADP-ribosyl cyclase (cyclase), are two prominent enzymes that catalyze the synthesis and hydrolysis of Cyclic ADP-ribose (cADPR), a Ca(2+) messenger molecule responsible for regulating a wide range of cellular functions. Although both use NAD as a substrate, the cyclase produces cADPR, whereas CD38 produces mainly ADP-ribose (ADPR). To elucidate the catalytic differences and the mechanism of cyclizing NAD, the crystal structure of a stable complex of the cyclase with an NAD analog, ribosyl-2'F-2'deoxynicotinamide adenine dinucleotide (ribo-2'-F-NAD), was determined. The results show that the analog was a substrate of the cyclase and that during the reaction, the nicotinamide group was released and a stable intermediate was formed. The terminal ribosyl unit at one end of the intermediate formed a close linkage with the catalytic residue (Glu-179), whereas the adenine ring at the other end stacked closely with Phe-174, suggesting that the latter residue is likely to be responsible for folding the linear substrate so that the two ends can be cyclized. Mutating Phe-174 indeed reduced cADPR production but enhanced ADPR production, converting the cyclase to be more CD38-like. Changing the equivalent residue in CD38, Thr-221 to Phe, correspondingly enhanced cADPR production, and the double mutation, Thr-221 to Phe and Glu-146 to Ala, effectively converted CD38 to a cyclase. This study provides the first detailed evidence of the cyclization process and demonstrates the feasibility of engineering the reactivity of the enzymes by mutation, setting the stage for the development of tools to manipulate cADPR metabolism in vivo.
Hiroshi Okamoto - One of the best experts on this subject based on the ideXlab platform.
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from insulin synthesis to secretion alternative splicing of type 2 ryanodine receptor gene is essential for insulin secretion in pancreatic β cells
The International Journal of Biochemistry & Cell Biology, 2017Co-Authors: Hiroshi Okamoto, Shin Takasawa, Yasuhiko YamamotoAbstract:Abstract Increases in the intracellular Ca 2+ concentration in pancreatic islets, resulting from the Ca 2+ mobilization from the intracellular source through the ryanodine receptor, are essential for insulin secretion by glucose. Cyclic ADP-ribose, a potent Ca 2+ mobilizing second messenger synthesized from NAD + by CD38, regulates the opening of ryanodine receptor. A novel ryanodine receptor mRNA (the islet-type ryanodine receptor) was found to be generated from the type 2 ryanodine receptor gene by the alternative splicing of exons 4 and 75. The islet-type ryanodine receptor mRNA is expressed in a variety of tissues such as pancreatic islets, cerebrum, cerebellum, and other neuro-endocrine cells, whereas the authentic type 2 ryanodine receptor mRNA (the heart-type ryanodine receptor) was found to be generated using GG/AG splicing of intron 75 and is expressed in the heart and the blood vessel. The islet-type ryanodine receptor caused a greater increase in the Ca 2+ release by caffeine when expressed in HEK293 cells pre-treated with Cyclic ADP-ribose, suggesting that the novel ryanodine receptor is an intracellular target for the CD38-Cyclic ADP-ribose signal system in mammalian cells and that the tissue-specific alternative splicing of type 2 ryanodine receptor mRNA plays an important role in the functioning of the Cyclic ADP-ribose-sensitive Ca 2+ release.
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generation of nicotinic acid adenine dinucleotide phosphate and Cyclic adp ribose by glucagon like peptide 1 evokes ca2 signal that is essential for insulin secretion in mouse pancreatic islets
Diabetes, 2008Co-Authors: Kwanghyun Park, Hiroshi Okamoto, Shin Takasawa, Miejae ImAbstract:OBJECTIVE— Glucagon-like peptide-1 (GLP-1) increases intracellular Ca 2+ concentrations ([Ca 2+ ] i ), resulting in insulin secretion from pancreatic β-cells. The molecular mechanism(s) of the GLP-1–mediated regulation of [Ca 2+ ] i was investigated. RESEARCH DESIGN AND METHODS— GLP-1–induced changes in [Ca 2+ ] i were measured in β-cells isolated from Cd38 +/+ and Cd38 −/− mice. Calcium-mobilizing second messengers were identified by measuring levels of nicotinic acid adenine dinucleotide phosphate (NAADP) and Cyclic ADP-ribose (ADPR), using a Cyclic enzymatic assay. To locate NAADP- and Cyclic ADPR–producing enzyme(s), cellular organelles were separated using the sucrose gradient method. RESULTS— A GLP-1–induced [Ca 2+ ] i increase showed a cooperative Ca 2+ signal, i.e., an initial [Ca 2+ ] i rise mediated by the action of NAADP that was produced in acidic organelles and a subsequent long-lasting increase of [Ca 2+ ] i by the action of Cyclic ADPR that was produced in plasma membranes and secretory granules. GLP-1 sequentially stimulated production of NAADP and Cyclic ADPR in the organelles through protein kinase A and cAMP-regulated guanine nucleotide exchange factor II. Furthermore, the results showed that NAADP production from acidic organelles governed overall Ca 2+ signals, including insulin secretion by GLP-1, and that in addition to CD38, enzymes capable of synthesizing NAADP and/or Cyclic ADPR were present in β-cells. These observations were supported by the study with Cd38 −/− β-cells, demonstrating production of NAADP, Cyclic ADPR, and Ca 2+ signal with normal insulin secretion stimulated by GLP-1. CONCLUSIONS— Our findings demonstrate that the GLP-1–mediated Ca 2+ signal for insulin secretion in pancreatic β-cells is a cooperative action of NAADP and Cyclic ADPR spatiotemporally formed by multiple enzymes.
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recent advances in physiological and pathological significance of nad metabolites roles of poly adp ribose and Cyclic adp ribose in insulin secretion and diabetogenesis
Nutrition Research Reviews, 2003Co-Authors: Hiroshi Okamoto, Shin TakasawaAbstract:Poly(ADP-ribose) synthetase/polymerase (PARP) activation causes NAD+ depletion in pancreatic beta-cells, which results in necrotic cell death. On the other hand, ADP-ribosyl cyclase/Cyclic ADP-ribose hydrolase (CD38) synthesizes Cyclic ADP-ribose from NAD+, which acts as a second messenger, mobilizing intracellular Ca2+ for insulin secretion in response to glucose in beta-cells. PARP also acts as a regenerating gene (Reg) transcription factor to induce beta-cell regeneration. This provides the new concept that NAD+ metabolism can control the cellular function through gene expression. Clinically, PARP could be one of the most important therapeutic targets; PARP inhibitors prevent cell death, maintain the formation of a second messenger, Cyclic ADP-ribose, to achieve cell function, and keep PARP functional as a transcription factor for cell regeneration.
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autoantibodies to cd38 adp ribosyl cyclase Cyclic adp ribose hydrolase in caucasian patients with diabetes effects on insulin release from human islets
Diabetes, 1999Co-Authors: Cinzia Pupilli, Hiroshi Okamoto, Shin Takasawa, Fabio Malavasi, Stefano Giannini, Piero Marchetti, R Lupi, Alessandro Antonelli, Ele FerranniniAbstract:The type II transmembrane glycoprotein CD38 (ADP-ribosyl cyclase/Cyclic ADP-ribose hydrolase) has been proposed as a mediator of insulin secretion from pancreatic beta-cells and as a candidate for autoimmune reactions in type 2 diabetes. We evaluated the presence of anti-CD38 autoantibodies in Caucasian patients with diabetes and investigated the effect of these antibodies on insulin secretion from isolated human pancreatic islets. The presence of anti-CD38 autoantibodies was evaluated by using Western blot analysis in 236 patients with type 2 diabetes (mean age 63 years), in 160 patients with type 1 diabetes (mean age 38 years), and in 159 nondiabetic subjects. Anti-CD38 autoantibody titers at least 3 SD above the mean value of the control group were found in 9.7% of type 2 diabetic patients and in 13.1% of type 1 diabetic patients (chi2 = 15.9, P = 0.0003 vs. 1.3% of control subjects). No significant differences were observed in sex distribution, current age, age at diabetes onset, BMI, fasting serum glucose, or glycemic control between anti-CD38+ and anti-CD38-diabetic patients in either the type 2 or type 1 diabetic groups. The effect of 23 anti-CD38- and 13 anti-CD38+ sera on insulin secretion at low (3.3 mmol/l) or high (16.7 mmol/l) medium glucose concentrations was evaluated in isolated human pancreatic islets. Data are medians (interquartile range). The anti-CD38+ sera potentiated insulin release both at low [95 (64) vs. 23 (12) microU/ml of control incubations, respectively, P < 0.0001] and high [271 (336) vs. a control of 55 (37) microU/ml, respectively, P = 0.001] medium glucose concentrations, whereas the anti-CD38- sera did not. Furthermore, in the pooled data from all 36 tested sera, insulin levels in the islet incubation medium were directly related to the anti-CD38 antibody titer. We conclude that autoantibodies to CD38 are associated with both type 1 and type 2 diabetes in Caucasian subjects. These autoantibodies exert a stimulatory effect on insulin secretion by cultured human islets. The role of this autoimmune reaction in the pathogenesis of diabetes remains to be elucidated.
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Cyclic adp ribose and inositol 1 4 5 trisphosphate as alternate second messengers for intracellular ca2 mobilization in normal and diabetic β cells
Journal of Biological Chemistry, 1998Co-Authors: Shin Takasawa, Toshiaki Katada, Koji Nata, Akira Tohgo, Ichiro Kato, Seiichi Kobayashi, Takako Akiyama, Michio Kuroki, Naoya Noguchi, Hiroshi OkamotoAbstract:Intracellular Ca2+ mobilization occurs in a variety of cellular processes and is mediated by two major systems, the inositol 1,4,5-trisphosphate (IP3) and Cyclic ADP-ribose (cADPR) systems. cADPR has been proposed to be a second messenger for insulin secretion induced by glucose in pancreatic β-cells (Takasawa, S., Nata, K., Yonekura, H., and Okamoto, H. (1993)Science 259, 370–373). Here we show that the cADPR signal system for insulin secretion is replaced by the IP3 system in diabetic β-cells such as ob/ob mouse islets and RINm5F cells. We measured the cADPR content in these β-cells by radioimmunoassay and found that the increase of the cADPR content by glucose did not occur in ob/ob mouse islets and RINm5F cells, whereas the increased cADPR level by glucose was observed in normal rat and mouse islets. Microsomes of these diabetic β-cells released Ca2+ in response to IP3 but not to cADPR. In the diabetic β-cells, CD38 (ADP-ribosyl cyclase/cADPR hydrolase) and type 2 ryanodine receptor mRNAs were scarcely detected and, in contrast, an increased expression of IP3receptor mRNAs was observed. The diabetic β-cells secreted insulin rather by carbamylcholine than by glucose.
Shin Takasawa - One of the best experts on this subject based on the ideXlab platform.
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from insulin synthesis to secretion alternative splicing of type 2 ryanodine receptor gene is essential for insulin secretion in pancreatic β cells
The International Journal of Biochemistry & Cell Biology, 2017Co-Authors: Hiroshi Okamoto, Shin Takasawa, Yasuhiko YamamotoAbstract:Abstract Increases in the intracellular Ca 2+ concentration in pancreatic islets, resulting from the Ca 2+ mobilization from the intracellular source through the ryanodine receptor, are essential for insulin secretion by glucose. Cyclic ADP-ribose, a potent Ca 2+ mobilizing second messenger synthesized from NAD + by CD38, regulates the opening of ryanodine receptor. A novel ryanodine receptor mRNA (the islet-type ryanodine receptor) was found to be generated from the type 2 ryanodine receptor gene by the alternative splicing of exons 4 and 75. The islet-type ryanodine receptor mRNA is expressed in a variety of tissues such as pancreatic islets, cerebrum, cerebellum, and other neuro-endocrine cells, whereas the authentic type 2 ryanodine receptor mRNA (the heart-type ryanodine receptor) was found to be generated using GG/AG splicing of intron 75 and is expressed in the heart and the blood vessel. The islet-type ryanodine receptor caused a greater increase in the Ca 2+ release by caffeine when expressed in HEK293 cells pre-treated with Cyclic ADP-ribose, suggesting that the novel ryanodine receptor is an intracellular target for the CD38-Cyclic ADP-ribose signal system in mammalian cells and that the tissue-specific alternative splicing of type 2 ryanodine receptor mRNA plays an important role in the functioning of the Cyclic ADP-ribose-sensitive Ca 2+ release.
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generation of nicotinic acid adenine dinucleotide phosphate and Cyclic adp ribose by glucagon like peptide 1 evokes ca2 signal that is essential for insulin secretion in mouse pancreatic islets
Diabetes, 2008Co-Authors: Kwanghyun Park, Hiroshi Okamoto, Shin Takasawa, Miejae ImAbstract:OBJECTIVE— Glucagon-like peptide-1 (GLP-1) increases intracellular Ca 2+ concentrations ([Ca 2+ ] i ), resulting in insulin secretion from pancreatic β-cells. The molecular mechanism(s) of the GLP-1–mediated regulation of [Ca 2+ ] i was investigated. RESEARCH DESIGN AND METHODS— GLP-1–induced changes in [Ca 2+ ] i were measured in β-cells isolated from Cd38 +/+ and Cd38 −/− mice. Calcium-mobilizing second messengers were identified by measuring levels of nicotinic acid adenine dinucleotide phosphate (NAADP) and Cyclic ADP-ribose (ADPR), using a Cyclic enzymatic assay. To locate NAADP- and Cyclic ADPR–producing enzyme(s), cellular organelles were separated using the sucrose gradient method. RESULTS— A GLP-1–induced [Ca 2+ ] i increase showed a cooperative Ca 2+ signal, i.e., an initial [Ca 2+ ] i rise mediated by the action of NAADP that was produced in acidic organelles and a subsequent long-lasting increase of [Ca 2+ ] i by the action of Cyclic ADPR that was produced in plasma membranes and secretory granules. GLP-1 sequentially stimulated production of NAADP and Cyclic ADPR in the organelles through protein kinase A and cAMP-regulated guanine nucleotide exchange factor II. Furthermore, the results showed that NAADP production from acidic organelles governed overall Ca 2+ signals, including insulin secretion by GLP-1, and that in addition to CD38, enzymes capable of synthesizing NAADP and/or Cyclic ADPR were present in β-cells. These observations were supported by the study with Cd38 −/− β-cells, demonstrating production of NAADP, Cyclic ADPR, and Ca 2+ signal with normal insulin secretion stimulated by GLP-1. CONCLUSIONS— Our findings demonstrate that the GLP-1–mediated Ca 2+ signal for insulin secretion in pancreatic β-cells is a cooperative action of NAADP and Cyclic ADPR spatiotemporally formed by multiple enzymes.
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recent advances in physiological and pathological significance of nad metabolites roles of poly adp ribose and Cyclic adp ribose in insulin secretion and diabetogenesis
Nutrition Research Reviews, 2003Co-Authors: Hiroshi Okamoto, Shin TakasawaAbstract:Poly(ADP-ribose) synthetase/polymerase (PARP) activation causes NAD+ depletion in pancreatic beta-cells, which results in necrotic cell death. On the other hand, ADP-ribosyl cyclase/Cyclic ADP-ribose hydrolase (CD38) synthesizes Cyclic ADP-ribose from NAD+, which acts as a second messenger, mobilizing intracellular Ca2+ for insulin secretion in response to glucose in beta-cells. PARP also acts as a regenerating gene (Reg) transcription factor to induce beta-cell regeneration. This provides the new concept that NAD+ metabolism can control the cellular function through gene expression. Clinically, PARP could be one of the most important therapeutic targets; PARP inhibitors prevent cell death, maintain the formation of a second messenger, Cyclic ADP-ribose, to achieve cell function, and keep PARP functional as a transcription factor for cell regeneration.
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autoantibodies to cd38 adp ribosyl cyclase Cyclic adp ribose hydrolase in caucasian patients with diabetes effects on insulin release from human islets
Diabetes, 1999Co-Authors: Cinzia Pupilli, Hiroshi Okamoto, Shin Takasawa, Fabio Malavasi, Stefano Giannini, Piero Marchetti, R Lupi, Alessandro Antonelli, Ele FerranniniAbstract:The type II transmembrane glycoprotein CD38 (ADP-ribosyl cyclase/Cyclic ADP-ribose hydrolase) has been proposed as a mediator of insulin secretion from pancreatic beta-cells and as a candidate for autoimmune reactions in type 2 diabetes. We evaluated the presence of anti-CD38 autoantibodies in Caucasian patients with diabetes and investigated the effect of these antibodies on insulin secretion from isolated human pancreatic islets. The presence of anti-CD38 autoantibodies was evaluated by using Western blot analysis in 236 patients with type 2 diabetes (mean age 63 years), in 160 patients with type 1 diabetes (mean age 38 years), and in 159 nondiabetic subjects. Anti-CD38 autoantibody titers at least 3 SD above the mean value of the control group were found in 9.7% of type 2 diabetic patients and in 13.1% of type 1 diabetic patients (chi2 = 15.9, P = 0.0003 vs. 1.3% of control subjects). No significant differences were observed in sex distribution, current age, age at diabetes onset, BMI, fasting serum glucose, or glycemic control between anti-CD38+ and anti-CD38-diabetic patients in either the type 2 or type 1 diabetic groups. The effect of 23 anti-CD38- and 13 anti-CD38+ sera on insulin secretion at low (3.3 mmol/l) or high (16.7 mmol/l) medium glucose concentrations was evaluated in isolated human pancreatic islets. Data are medians (interquartile range). The anti-CD38+ sera potentiated insulin release both at low [95 (64) vs. 23 (12) microU/ml of control incubations, respectively, P < 0.0001] and high [271 (336) vs. a control of 55 (37) microU/ml, respectively, P = 0.001] medium glucose concentrations, whereas the anti-CD38- sera did not. Furthermore, in the pooled data from all 36 tested sera, insulin levels in the islet incubation medium were directly related to the anti-CD38 antibody titer. We conclude that autoantibodies to CD38 are associated with both type 1 and type 2 diabetes in Caucasian subjects. These autoantibodies exert a stimulatory effect on insulin secretion by cultured human islets. The role of this autoimmune reaction in the pathogenesis of diabetes remains to be elucidated.
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autoantibodies against cd38 adp ribosyl cyclase Cyclic adp ribose hydrolase that impair glucose induced insulin secretion in noninsulin dependent diabetes patients
Journal of Clinical Investigation, 1998Co-Authors: Fumiko Ikehata, Shin Takasawa, Jo Satoh, Koji Nata, Akira Tohgo, Tetsuya Nakazawa, Ichiro Kato, Seiichi Kobayashi, Takako Akiyama, Takayoshi ToyotaAbstract:Cyclic ADP-ribose (cADPR) has been shown to be a mediator for intracellular Ca2+ mobilization for insulin secretion by glucose in pancreatic beta cells, and CD38 shows both ADP-ribosyl cyclase to synthesize cADPR from NAD+ and cADPR hydrolase to hydrolyze cADPR to ADP-ribose. We show here that 13.8% of Japanese non-insulin-dependent diabetes (NIDDM) patients examined have autoantibodies against CD38 and that the sera containing anti-CD38 autoantibodies inhibit the ADP-ribosyl cyclase activity of CD38 (P
Antony Galione - One of the best experts on this subject based on the ideXlab platform.
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click Cyclic adp ribose a neutral second messenger mimic
Chemical Communications, 2014Co-Authors: Joanna M Swarbrick, Richard Graeff, Antony Galione, Clive Garnham, Mark P Thomas, Barry V L PotterAbstract:Analogues of the potent Ca2+ releasing second messenger Cyclic ADP-ribose (cADPR) with a 1,2,3-triazole pyrophosphate bioisostere were synthesised by click-mediated macrocyclisation. The ability to activate Ca2+ release was surprisingly retained, and hydrolysis of cADPR by CD38 could also be inhibited, illustrating the potential of this approach to design drug-like signalling pathway modulators.
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adp ribosyl cyclase and Cyclic adp ribose hydrolase act as a redox sensor a primary role for Cyclic adp ribose in hypoxic pulmonary vasoconstriction
Journal of Biological Chemistry, 2001Co-Authors: Heather Wilson, Antony Galione, Michelle Dipp, Justyn M Thomas, A M EvansAbstract:Abstract Hypoxic pulmonary vasoconstriction is unique to pulmonary arteries and serves to match lung perfusion to ventilation. However, in disease states this process can promote hypoxic pulmonary hypertension. Hypoxic pulmonary vasoconstriction is associated with increased NADH levels in pulmonary artery smooth muscle and with intracellular Ca2+ release from ryanodine-sensitive stores. Because Cyclic ADP-ribose (cADPR) regulates ryanodine receptors and is synthesized from β-NAD+, we investigated the regulation by β-NADH of cADPR synthesis and metabolism and the role of cADPR in hypoxic pulmonary vasoconstriction. Significantly higher rates of cADPR synthesis occurred in smooth muscle homogenates of pulmonary arteries, compared with homogenates of systemic arteries. When the β-NAD+:β-NADH ratio was reduced, the net amount of cADPR accumulated increased. This was due, at least in part, to the inhibition of cADPR hydrolase by β-NADH. Furthermore, hypoxia induced a 10-fold increase in cADPR levels in pulmonary artery smooth muscle, and a membrane-permeant cADPR antagonist, 8-bromo-cADPR, abolished hypoxic pulmonary vasoconstriction in pulmonary artery rings. We propose that the cellular redox state may be coupled via an increase in β-NADH levels to enhanced cADPR synthesis, activation of ryanodine receptors, and sarcoplasmic reticulum Ca2+ release. This redox-sensing pathway may offer new therapeutic targets for hypoxic pulmonary hypertension.
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a ca2 release mechanism gated by the novel pyridine nucleotide naadp
Trends in Pharmacological Sciences, 1997Co-Authors: Armando A. Genazzani, Antony GalioneAbstract:The mobilization of Ca2+ from intra- cellular stores constitutes an im- portant component of receptor- mediated Caz+ signalling. Two related families of intracellular Ca2+ release channels that mediate this process are inositol (1,4,5)trisphosphate (II’,) receptors and ryanodine receptors. There is considerable evidence that the pyridine nucleotide metabolite, Cyclic ADP-ribose (cADPR), is a regu- lator of ryanodine receptor-mediated Ca2+ release. In this article, the prop- erties of a possible novel Ca2+ release mechanism activated by another pyridine nucleotide-derived, puta- tive intracellular messenger, nicotinic acid adenine dinucleotide phosphate (NAADP) are discussed. NAADP-induced Ca2+ release As the
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nitric oxide induced mobilization of intracellular calcium via the Cyclic adp ribose signaling pathway
Journal of Biological Chemistry, 1996Co-Authors: Nick Willmott, Hon Cheung Lee, Timothy F Walseth, Jaswinder K Sethi, Alison M White, Antony GalioneAbstract:Cyclic adenosine diphosphate ribose (cADPR) is a potent endogenous calcium-mobilizing agent synthesized from β-NAD+ by ADP-ribosyl cyclases in sea urchin eggs and in several mammalian cells (Galione, A., and White, A.(1994) Trends Cell Biol. 4, 431-436). Pharmacological studies suggest that cADPR is an endogenous modulator of Ca2+-induced Ca2+ release mediated by ryanodine-sensitive Ca2+ release channels. An unresolved question is whether cADPR can act as a Ca2+-mobilizing intracellular messenger. We show that exogenous application of nitric oxide (NO) mobilizes Ca2+ from intracellular stores in intact sea urchin eggs and that it releases Ca2+ and elevates cADPR levels in egg homogenates. 8-Amino-cADPR, a selective competitive antagonist of cADPR-mediated Ca2+ release, and nicotinamide, an inhibitor of ADP-ribosyl cyclase, inhibit the Ca2+-mobilizing actions of NO, while, heparin, a competitive antagonist of the inositol 1,4,5-trisphosphate receptor, did not affect NO-induced Ca2+ release. Since the Ca2+-mobilizing effects of NO can be mimicked by cGMP, are inhibited by the cGMP-dependent-protein kinase inhibitor, Rp-8-pCPT-cGMPS, and in egg homogenates show a requirement for the guanylyl cyclase substrate, GTP, we suggest a novel action of NO in mobilizing intracellular calcium from microsomal stores via a signaling pathway involving cGMP and cADPR. These results suggest that cADPR has the capacity to act as a Ca2+-mobilizing intracellular messenger.
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Cyclic ADP-ribose, the ADP-ribosyl cyclase pathway and calcium signalling
Molecular and Cellular Endocrinology, 1994Co-Authors: Antony GalioneAbstract:Cyclic adenosine diphosphate-ribose, an endogenous metabolite of nicotinamide adenine dinucleotide was first characterized as a potent Ca2+ mobilizing agent in sea urchin eggs. Mounting evidence points to it being an endogenous activator of Ca(2+)-induced Ca2+ release by non-skeletal muscle ryanodine receptors in several invertebrate and mammalian cell types. Cyclic adenosine diphosphate-ribose is synthesized by adenosine diphosphate-ribosyl cyclases, which have been found to be widespread enzymes. Recent data suggests that Cyclic adenosine diphosphate-ribose may function as a second messenger in sea urchin eggs at fertilization and in stimulus secretion coupling in pancreatic beta-cells. A second messenger role for Cyclic adenosine diphosphate-ribose requires that its intracellular levels be under the control of extracellular stimuli. Another second messenger, cGMP, stimulates the synthesis of Cyclic adenosine diphosphate-ribose from nicotinamide adenine dinucleotide by activating the adenosine diphosphate-ribosyl cyclase pathway in sera urchin eggs and egg homogenates, suggesting that Cyclic adenosine diphosphate-ribose may be an intracellular messenger for cell surface receptors or nitric oxide, which activate cGMP-producing guanylate cyclases. Cyclic adenosine diphosphate-ribose may have a similar role to inositol trisphosphate in controlling intracellular calcium signalling with these two calcium-mobilizing second messengers activating ryanodine receptors and inositol trisphosphate receptors respectively.
Richard Graeff - One of the best experts on this subject based on the ideXlab platform.
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click Cyclic adp ribose a neutral second messenger mimic
Chemical Communications, 2014Co-Authors: Joanna M Swarbrick, Richard Graeff, Antony Galione, Clive Garnham, Mark P Thomas, Barry V L PotterAbstract:Analogues of the potent Ca2+ releasing second messenger Cyclic ADP-ribose (cADPR) with a 1,2,3-triazole pyrophosphate bioisostere were synthesised by click-mediated macrocyclisation. The ability to activate Ca2+ release was surprisingly retained, and hydrolysis of cADPR by CD38 could also be inhibited, illustrating the potential of this approach to design drug-like signalling pathway modulators.
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determination of adp ribosyl cyclase activity Cyclic adp ribose and nicotinic acid adenine dinucleotide phosphate in tissue extracts
Methods of Molecular Biology, 2013Co-Authors: Richard Graeff, Hon Cheung LeeAbstract:Abstract Cyclic ADP-ribose (cADPR) is a novel second messenger that releases calcium from intracellular stores. Although first shown to release calcium in the sea urchin egg, cADPR has been shown since to be active in a variety of cells and tissues, from plant to human. cADPR stimulates calcium release via ryanodine receptors although the mechanism is still not completely understood. cADPR is produced enzymatically from NAD by ADP-ribosyl cyclases; several of these proteins have been identified including one isolated from Aplysia californica, two types found in mammals (CD38 and CD157), and three forms in sea urchin. A cyclase activity has been measured in extracts from Arabidopsis thaliana although the protein is still unidentified. Nicotinic acid adenine dinucleotide phosphate (NAADP) is another novel messenger that releases calcium from internal stores and is produced by these same enzymes by an exchange reaction. NAADP targets lysosomal stores whereas cADPR releases calcium from the endoplasmic reticulum. Due to their importance in cell signaling, cADPR and NAADP have been the focus of numerous investigations over the last 25 years. This chapter describes several assay methods for the measurements of cADPR and NAADP concentration and cyclase activity in extracts from cells.
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Mechanism of cyclizing NAD to Cyclic ADP-ribose by ADP-ribosyl cyclase and CD38
Journal of Biological Chemistry, 2009Co-Authors: Richard Graeff, Quan Hao, Masayo Kotaka, Norman Oppenheimer, Irina A Kriksunov, Qun Liu, Hon Cheung LeeAbstract:Mammalian CD38 and its Aplysia homolog, ADP-ribosyl cyclase (cyclase), are two prominent enzymes that catalyze the synthesis and hydrolysis of Cyclic ADP-ribose (cADPR), a Ca(2+) messenger molecule responsible for regulating a wide range of cellular functions. Although both use NAD as a substrate, the cyclase produces cADPR, whereas CD38 produces mainly ADP-ribose (ADPR). To elucidate the catalytic differences and the mechanism of cyclizing NAD, the crystal structure of a stable complex of the cyclase with an NAD analog, ribosyl-2'F-2'deoxynicotinamide adenine dinucleotide (ribo-2'-F-NAD), was determined. The results show that the analog was a substrate of the cyclase and that during the reaction, the nicotinamide group was released and a stable intermediate was formed. The terminal ribosyl unit at one end of the intermediate formed a close linkage with the catalytic residue (Glu-179), whereas the adenine ring at the other end stacked closely with Phe-174, suggesting that the latter residue is likely to be responsible for folding the linear substrate so that the two ends can be cyclized. Mutating Phe-174 indeed reduced cADPR production but enhanced ADPR production, converting the cyclase to be more CD38-like. Changing the equivalent residue in CD38, Thr-221 to Phe, correspondingly enhanced cADPR production, and the double mutation, Thr-221 to Phe and Glu-146 to Ala, effectively converted CD38 to a cyclase. This study provides the first detailed evidence of the cyclization process and demonstrates the feasibility of engineering the reactivity of the enzymes by mutation, setting the stage for the development of tools to manipulate cADPR metabolism in vivo.
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subcellular localization of Cyclic adp ribosyl cyclase and Cyclic adp ribose hydrolase activities in porcine airway smooth muscle
Biochimica et Biophysica Acta, 2000Co-Authors: Thomas A White, Richard Graeff, Hon Cheung Lee, Timothy F Walseth, Y S Prakash, Gary C Sieck, Sonja E Johnson, Cyrus Munshi, Mathur S KannanAbstract:Recent studies have provided evidence for a role of Cyclic ADP-ribose (cADPR) in the regulation of intracellular calcium in smooth muscles of the intestine, blood vessels and airways. We investigated the presence and subcellular localization of ADP-ribosyl cyclase, the enzyme that catalyzes the conversion of beta-NAD(+) to cADPR, and cADPR hydrolase, the enzyme that degrades cADPR to ADPR, in tracheal smooth muscle (TSM). Sucrose density fractionation of TSM crude membranes provided evidence that ADP-ribosyl cyclase and cADPR hydrolase activities were associated with a fraction enriched in 5'-nucleotidase activity, a plasma membrane marker enzyme, but not in a fraction enriched in either sarcoplasmic endoplasmic reticulum calcium ATPase or ryanodine receptor channels, both sarcoplasmic reticulum markers. The ADP-ribosyl cyclase and cADPR hydrolase activities comigrated at a molecular weight of approximately 40 kDa on SDS-PAGE. This comigration was confirmed by gel filtration chromatography. Investigation of kinetics yielded K(m) values of 30.4+/-1.5 and 695. 3+/-171.2 microM and V(max) values of 330.4+/-90 and 102.8+/-17.1 nmol/mg/h for ADP-ribosyl cyclase and cADPR hydrolase, respectively. These results suggest a possible role for cADPR as an endogenous modulator of [Ca(2+)](i) in porcine TSM cells.
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Cyclic gmp dependent and independent effects on the synthesis of the calcium messengers Cyclic adp ribose and nicotinic acid adenine dinucleotide phosphate
Journal of Biological Chemistry, 1998Co-Authors: Richard Graeff, Luisa Franco, A De FloraAbstract:Abstract Cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP) have been shown to mobilize intracellular Ca2+ stores by totally independent mechanisms, which are pharmacologically distinct from that activated by inositol trisphosphate. Although cADPR and NAADP are structurally and functionally different, they can be synthesized by a single enzyme having ADP-ribosyl cyclase activity. In this study, three different assays were used to measure the metabolism of cADPR in sea urchin egg homogenates including a radioimmunoassay, a Ca2+release assay, and a thin layer chromatographic assay. Soluble and membrane-bound ADP-ribosyl cyclases were identified and both cyclized NAD to produce cADPR. The soluble cyclase was half-maximally stimulated by 5.3 μm cGMP, but not by cAMP, while the membrane-bound form was independent of cGMP. The two forms of the cyclase were also different in the pH dependence of utilizing nicotinamide guanine dinucleotide (NGD), a guanine analog of NAD, as substrate, indicating they are two separate enzymes. The stimulatory effect of cGMP required ATP or ATPγS (adenosine 5′-O-(3-thiotriphosphate)) and a cGMP-dependent kinase activity was shown to be present in the soluble fraction. The degradation of cADPR to ADP-ribose was catalyzed by cADPR hydrolase, which was found to be predominantly associated with membranes. Similar to the membrane-bound cyclase, the cADPR hydrolase activity was also independent of cGMP. Both the soluble and membrane fractions also catalyzed the synthesis of NAADP through exchanging the nicotinamide group of NADP with nicotinic acid (NA). The base-exchange activity was independent of cGMP and the half-maximal concentrations of NADP and NA needed were about 0.2 mm and 10 mm, respectively. The exchange reaction showed a preference for acidic pH, contrasting with the neutral pH optimum of the cyclase activities. The complex metabolic pathways characterized in this study indicate that there may be a multitude of regulatory mechanisms for controlling the endogenous concentrations of cADPR and NAADP.
