1
|
Hao H, Jia X, Ren T, Du Y, Wang J. Novel insight into the mechanism underlying synergistic cytotoxicity from two components in 5-Fluorouracil-phenylalanine co-crystal based on cell metabolomics. Eur J Pharm Biopharm 2022; 180:181-189. [DOI: 10.1016/j.ejpb.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 09/21/2022] [Accepted: 10/03/2022] [Indexed: 11/04/2022]
|
2
|
Terrar DA. Endolysosomal Calcium Release and Cardiac Physiology. Cell Calcium 2022; 104:102565. [DOI: 10.1016/j.ceca.2022.102565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 02/20/2022] [Accepted: 02/21/2022] [Indexed: 11/25/2022]
|
3
|
Li ZH, King TP, Ayong L, Asady B, Cai X, Rahman T, Vella SA, Coppens I, Patel S, Moreno SNJ. A plastid two-pore channel essential for inter-organelle communication and growth of Toxoplasma gondii. Nat Commun 2021; 12:5802. [PMID: 34608145 PMCID: PMC8490419 DOI: 10.1038/s41467-021-25987-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/06/2021] [Indexed: 01/04/2023] Open
Abstract
Two-pore channels (TPCs) are a ubiquitous family of cation channels that localize to acidic organelles in animals and plants to regulate numerous Ca2+-dependent events. Little is known about TPCs in unicellular organisms despite their ancient origins. Here, we characterize a TPC from Toxoplasma gondii, the causative agent of toxoplasmosis. TgTPC is a member of a novel clad of TPCs in Apicomplexa, distinct from previously identified TPCs and only present in coccidians. We show that TgTPC localizes not to acidic organelles but to the apicoplast, a non-photosynthetic plastid found in most apicomplexan parasites. Conditional silencing of TgTPC resulted in progressive loss of apicoplast integrity, severely affecting growth and the lytic cycle. Isolation of TPC null mutants revealed a selective role for TPCs in replication independent of apicoplast loss that required conserved residues within the pore-lining region. Using a genetically-encoded Ca2+ indicator targeted to the apicoplast, we show that Ca2+ signals deriving from the ER but not from the extracellular space are selectively transmitted to the lumen. Deletion of the TgTPC gene caused reduced apicoplast Ca2+ uptake and membrane contact site formation between the apicoplast and the ER. Fundamental roles for TPCs in maintaining organelle integrity, inter-organelle communication and growth emerge.
Collapse
Affiliation(s)
- Zhu-Hong Li
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA
| | - Thayer P King
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA
| | - Lawrence Ayong
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA
| | - Beejan Asady
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Heath, Baltimore, MD, 21205, USA
| | - Xinjiang Cai
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, USA
| | - Stephen A Vella
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Heath, Baltimore, MD, 21205, USA
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK
| | - Silvia N J Moreno
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA. .,Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA.
| |
Collapse
|
4
|
Nicotinamide Inhibits Self-renewal and Induces Granulocyte Differentiation of Multipotent Progenitor Cells. Stem Cell Rev Rep 2020; 16:1335-1342. [PMID: 32789803 DOI: 10.1007/s12015-020-10019-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Nicotinamide (NAM) a form of vitamin B3, is an essential precursor of NAD. This dinucleotide (pyridine nucleotide) participates in the regulation of fundamental processes including transcription, cell cycle progression and DNA repair. Here we assessed the effect of NAM on myeloid differentiation of the IL-3 dependent, multipotent hematopoietic progenitor cell line FDCP-Mix. We found that NAM reduces the pSTAT5 signaling response, cell cycling and self-renewal potential. It initiates an atypical program of myeloid differentiation that results in the emergence of granulocytic cells in the absence of added myeloid differentiation factors. NAM did not affect the expression the of cell surface granulocyte marker GR1 but led to a strong downregulation of MHC-II molecules. Taken together our data show that NAM induces a differentiation program in hematopoietic progenitors prompting them to undergo differentiation along the granulocyte path without reaching the status of fully developed granulocytes. Graphical abstract.
Collapse
|
5
|
Chini CCS, Tarragó MG, Chini EN. NAD and the aging process: Role in life, death and everything in between. Mol Cell Endocrinol 2017; 455:62-74. [PMID: 27825999 PMCID: PMC5419884 DOI: 10.1016/j.mce.2016.11.003] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 09/22/2016] [Accepted: 11/03/2016] [Indexed: 12/11/2022]
Abstract
Life as we know it cannot exist without the nucleotide nicotinamide adenine dinucleotide (NAD). From the simplest organism, such as bacteria, to the most complex multicellular organisms, NAD is a key cellular component. NAD is extremely abundant in most living cells and has traditionally been described to be a cofactor in electron transfer during oxidation-reduction reactions. In addition to participating in these reactions, NAD has also been shown to play a key role in cell signaling, regulating several pathways from intracellular calcium transients to the epigenetic status of chromatin. Thus, NAD is a molecule that provides an important link between signaling and metabolism, and serves as a key molecule in cellular metabolic sensoring pathways. Importantly, it has now been clearly demonstrated that cellular NAD levels decline during chronological aging. This decline appears to play a crucial role in the development of metabolic dysfunction and age-related diseases. In this review we will discuss the molecular mechanisms responsible for the decrease in NAD levels during aging. Since other reviews on this subject have been recently published, we will concentrate on presenting a critical appraisal of the current status of the literature and will highlight some controversial topics in the field. In particular, we will discuss the potential role of the NADase CD38 as a driver of age-related NAD decline.
Collapse
Affiliation(s)
- Claudia C S Chini
- Signal Transduction Laboratory, Kogod Aging Center, Department of Anesthesiology, Oncology Research, GI Signaling Center, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Mariana G Tarragó
- Signal Transduction Laboratory, Kogod Aging Center, Department of Anesthesiology, Oncology Research, GI Signaling Center, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Eduardo N Chini
- Signal Transduction Laboratory, Kogod Aging Center, Department of Anesthesiology, Oncology Research, GI Signaling Center, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
| |
Collapse
|
6
|
Deshpande DA, Guedes AGP, Lund FE, Subramanian S, Walseth TF, Kannan MS. CD38 in the pathogenesis of allergic airway disease: Potential therapeutic targets. Pharmacol Ther 2016; 172:116-126. [PMID: 27939939 DOI: 10.1016/j.pharmthera.2016.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CD38 is an ectoenzyme that catalyzes the conversion of β-nicotinamide adenine dinucleotide (β-NAD) to cyclic adenosine diphosphoribose (cADPR) and adenosine diphosphoribose (ADPR) and NADP to nicotinic acid adenine dinucleotide phosphate (NAADP) and adenosine diphosphoribose-2'-phosphate (ADPR-P). The metabolites of NAD and NADP have roles in calcium signaling in different cell types including airway smooth muscle (ASM) cells. In ASM cells, inflammatory cytokines augment CD38 expression and to a greater magnitude in cells from asthmatics, indicating a greater capacity for the generation of cADPR and ADPR in ASM from asthmatics. CD38 deficient mice develop attenuated airway responsiveness to inhaled methacholine following allergen sensitization and challenge compared to wild-type mice indicating its potential role in asthma. Regulation of CD38 expression in ASM cells is achieved by mitogen activated protein kinases, specific isoforms of PI3 kinases, the transcription factors NF-κB and AP-1, and post-transcriptionally by microRNAs. This review will focus on the role of CD38 in intracellular calcium regulation in ASM, contribution to airway inflammation and airway hyperresponsiveness in mouse models of allergic airway inflammation, the transcriptional and post-transcriptional mechanisms of regulation of expression, and outline approaches to inhibit its expression and activity.
Collapse
Affiliation(s)
| | - Alonso G P Guedes
- Department of Veterinary Clinical Sciences, University of Minnesota at Twin Cities, USA
| | - Frances E Lund
- Department of Microbiology, University of Alabama at Birmingham, USA
| | | | - Timothy F Walseth
- Department of Pharmacology, University of Minnesota at Twin Cities, USA
| | - Mathur S Kannan
- Department of Veterinary and Biomedical Sciences, University of Minnesota at Twin Cities, USA.
| |
Collapse
|
7
|
Guedes AGP, Jude JA, Paulin J, Rivero-Nava L, Kita H, Lund FE, Kannan MS. Airway responsiveness in CD38-deficient mice in allergic airway disease: studies with bone marrow chimeras. Am J Physiol Lung Cell Mol Physiol 2015; 308:L485-93. [PMID: 25575514 DOI: 10.1152/ajplung.00227.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CD38 is a cell-surface protein involved in calcium signaling and contractility of airway smooth muscle. It has a role in normal airway responsiveness and in airway hyperresponsiveness (AHR) developed following airway exposure to IL-13 and TNF-α but appears not to be critical to airway inflammation in response to the cytokines. CD38 is also involved in T cell-mediated immune response to protein antigens. In this study, we assessed the contribution of CD38 to AHR and inflammation to two distinct allergens, ovalbumin and the epidemiologically relevant environmental fungus Alternaria. We also generated bone marrow chimeras to assess whether Cd38(+/+) inflammatory cells would restore AHR in the CD38-deficient (Cd38(-/-)) hosts following ovalbumin challenge. Results show that wild-type (WT) mice develop greater AHR to inhaled methacholine than Cd38(-/-) mice following challenge with either allergen, with comparable airway inflammation. Reciprocal bone marrow transfers did not change the native airway phenotypic differences between WT and Cd38(-/-) mice, indicating that the lower airway reactivity of Cd38(-/-) mice stems from Cd38(-/-) lung parenchymal cells. Following bone marrow transfer from either source and ovalbumin challenge, the phenotype of Cd38(-/-) hosts was partially reversed, whereas the airway phenotype of the WT hosts was preserved. Airway inflammation was similar in Cd38(-/-) and WT chimeras. These results indicate that loss of CD38 on hematopoietic cells is not sufficient to prevent AHR and that the magnitude of airway inflammation is not the predominant underlying determinant of AHR in mice.
Collapse
Affiliation(s)
- Alonso G P Guedes
- Department of Surgical and Radiological Sciences, University of California, Davis, California
| | - Joseph A Jude
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jaime Paulin
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota
| | | | - Hirohito Kita
- Departments of Immunology and Medicine, Mayo Clinic, Rochester, Minnesota
| | - Frances E Lund
- Trudeau Institute, Saranac Lake, New York; Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Mathur S Kannan
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota
| |
Collapse
|
8
|
Schönknecht G. Calcium Signals from the Vacuole. PLANTS (BASEL, SWITZERLAND) 2013; 2:589-614. [PMID: 27137394 PMCID: PMC4844392 DOI: 10.3390/plants2040589] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 09/21/2013] [Accepted: 09/26/2013] [Indexed: 01/13/2023]
Abstract
The vacuole is by far the largest intracellular Ca(2+) store in most plant cells. Here, the current knowledge about the molecular mechanisms of vacuolar Ca(2+) release and Ca(2+) uptake is summarized, and how different vacuolar Ca(2+) channels and Ca(2+) pumps may contribute to Ca(2+) signaling in plant cells is discussed. To provide a phylogenetic perspective, the distribution of potential vacuolar Ca(2+) transporters is compared for different clades of photosynthetic eukaryotes. There are several candidates for vacuolar Ca(2+) channels that could elicit cytosolic [Ca(2+)] transients. Typical second messengers, such as InsP₃ and cADPR, seem to trigger vacuolar Ca(2+) release, but the molecular mechanism of this Ca(2+) release still awaits elucidation. Some vacuolar Ca(2+) channels have been identified on a molecular level, the voltage-dependent SV/TPC1 channel, and recently two cyclic-nucleotide-gated cation channels. However, their function in Ca(2+) signaling still has to be demonstrated. Ca(2+) pumps in addition to establishing long-term Ca(2+) homeostasis can shape cytosolic [Ca(2+)] transients by limiting their amplitude and duration, and may thus affect Ca(2+) signaling.
Collapse
Affiliation(s)
- Gerald Schönknecht
- Department of Botany, Oklahoma State University, Stillwater, OK 74078, USA.
| |
Collapse
|
9
|
Congleton J, Jiang H, Malavasi F, Lin H, Yen A. ATRA-induced HL-60 myeloid leukemia cell differentiation depends on the CD38 cytosolic tail needed for membrane localization, but CD38 enzymatic activity is unnecessary. Exp Cell Res 2010; 317:910-9. [PMID: 21156171 DOI: 10.1016/j.yexcr.2010.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 11/19/2010] [Accepted: 12/02/2010] [Indexed: 01/13/2023]
Abstract
Leukocyte antigen CD38 expression is an early marker of all-trans retinoic acid (ATRA) stimulated differentiation in the leukemic cell line HL-60. It promotes induced myeloid maturation when overexpressed, whereas knocking it down is inhibitory. It is a type II membrane protein with an extracellular C-terminal enzymatic domain with NADase/NADPase and ADPR cyclase activity and a short cytoplasmic N-terminal tail. Here we determined whether CD38 enzymatic activity or the cytoplasmic tail is required for ATRA-induced differentiation. Neither a specific CD38 ectoenzyme inhibitor nor a point mutation that cripples enzymatic activity (CD38 E226Q) diminishes ATRA-induced differentiation or G1/0 arrest. In contrast a cytosolic deletion mutation (CD38 Δ11-20) prevents membrane expression and inhibits differentiation and G1/0 arrest. These results may be consistent with disrupting the function of critical molecules necessary for membrane-expressed CD38 signal transduction. One candidate molecule is the Src family kinase Fgr, which failed to undergo ATRA-induced upregulation in CD38 Δ11-20 expressing cells. Another is Vav1, which also showed only basal expression after ATRA treatment in CD38 Δ11-20 expressing cells. Therefore, the ability of CD38 to propel ATRA-induced myeloid differentiation and G1/0 arrest is unimpaired by loss of its ectoenzyme activity. However a cytosolic tail deletion mutation disrupted membrane localization and inhibited differentiation. ATRA-induced differentiation thus does not require the CD38 ectoenzyme function, but is dependent on a membrane receptor function.
Collapse
Affiliation(s)
- Johanna Congleton
- Department of Biomedical Sciences, Veterinary Research Tower, Cornell University, Ithaca, NY 14853, USA
| | | | | | | | | |
Collapse
|
10
|
Zhang H, Graeff R, Chen Z, Zhang L, Zhang L, Lee H, Hao Q. Dynamic conformations of the CD38-mediated NAD cyclization captured in a single crystal. J Mol Biol 2010; 405:1070-8. [PMID: 21134381 DOI: 10.1016/j.jmb.2010.11.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 11/22/2010] [Accepted: 11/23/2010] [Indexed: 10/18/2022]
Abstract
The extracellular domain of human CD38 is a multifunctional enzyme involved in the metabolism of two Ca(2+) messengers: cyclic ADP-ribose and nicotinic acid adenine dinucleotide phosphate. When NAD is used as substrate, CD38 predominantly hydrolyzes it to ADP-ribose, with a trace amount of cyclic ADP-ribose produced through cyclization of the substrate. However, mutation of a key residue at the active site, E146, inhibits the hydrolysis activity of CD38 but greatly increases its cyclization activity. To understand the role of the residue E146 in the catalytic process, we determined the crystal structure of the E146A mutant protein with a substrate analogue, arabinosyl-2'-fluoro-deoxy-nicotinamide adenine dinucleotide. The structure captured the enzymatic reaction intermediates in six different conformations in a crystallographic asymmetric unit. The structural results indicate a folding-back process for the adenine ring of the substrate and provide the first multiple snapshots of the process. Our approach of utilizing multiple molecules in the crystallographic asymmetric unit should be generally applicable for capturing the dynamic nature of enzymatic catalysis.
Collapse
Affiliation(s)
- HongMin Zhang
- Department of Physiology, The University of Hong Kong, Hong Kong SAR, China
| | | | | | | | | | | | | |
Collapse
|
11
|
Hartman WR, Pelleymounter LL, Moon I, Kalari K, Liu M, Wu TY, Escande C, Nin V, Chini EN, Weinshilboum RM. CD38 expression, function, and gene resequencing in a human lymphoblastoid cell line-based model system. Leuk Lymphoma 2010; 51:1315-25. [PMID: 20470215 DOI: 10.3109/10428194.2010.483299] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CD38 is an ecto-enzyme that hydrolyzes NAD. Its expression is a prognostic marker for chronic lymphocytic leukemia. We have characterized individual variation in CD38 expression in lymphoblastoid cell lines from 288 healthy subjects of three ethnicities. Expression varied widely, with significant differences among ethnic groups, and was correlated significantly with CD38 enzymatic activity and protein levels. The CD38 gene was then resequenced using DNA from the same cell lines, with the identification of 53 single nucleotide polymorphisms (SNPs) and one indel, 39 novel. One SNP, rs1130169, was significantly associated with CD38 mRNA expression and explained a portion of the difference in expression among ethnic groups. EMS assay showed nuclear protein binding at or near this SNP. We also determined that variation in CD38 expression in these cell lines was associated with variation in antineoplastic drug sensitivity. These results represent a step toward understanding mechanisms involved in CD38 expression.
Collapse
Affiliation(s)
- William R Hartman
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Chini EN. CD38 as a regulator of cellular NAD: a novel potential pharmacological target for metabolic conditions. Curr Pharm Des 2009; 15:57-63. [PMID: 19149603 DOI: 10.2174/138161209787185788] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
CD38 is a multifunctional enzyme that uses nicotinamide adenine dinucleotide (NAD) as a substrate to generate second messengers. Recently, CD38 was also identified as one of the main cellular NADases in mammalian tissues and appears to regulate cellular levels of NAD in multiple tissues and cells. Due to the emerging role of NAD as a key molecule in multiple signaling pathways, and metabolic conditions it is imperative to determine the cellular mechanisms that regulate the synthesis and degradation of this nucleotide. In fact, recently it has been shown that NAD participates in multiple physiological processes such as insulin secretion, control of energy metabolism, neuronal and cardiac cell survival, airway constriction, asthma, aging and longevity. The discovery of CD38 as the main cellular NADase in mammalian tissues, and the characterization of its role on the control of cellular NAD levels indicate that CD38 may serve as a pharmacological target for multiple conditions.
Collapse
Affiliation(s)
- Eduardo Nunes Chini
- Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
| |
Collapse
|
13
|
Abstract
Cells possess multiple calcium ion (Ca2+) stores and multiple messenger molecules to mobilize them. These include d-myo-inositol 1,4,5-trisphosphate (IP(3)), cyclic adenosine diphosphoribose (cADPR), and the most recently identified Ca2+-mobilizing messenger, nicotinic acid adenine dinucleotide phosphate (NAADP), which acts on a wide spectrum of cells, from plant cells to mammalian cells. Accumulating evidence indicates that NAADP targets both acidic (lysosome-like) Ca2+ stores and endoplasmic reticular stores. Recent studies in invertebrate and mammalian cells suggest that NAADP provides an initiating Ca2+ signal, which is amplified by cADPR- or IP(3)-dependent mechanisms (or both) through Ca2+-induced Ca2+ release. Diverse stimuli activate a rapid rise of endogenous NAADP concentration, resulting in severalfold increases of NAADP over basal values within seconds. The enzyme CD38 can catalyze both the synthesis and hydrolysis of NAADP, making it ideal for effecting the rapid metabolism of NAADP. The crystal structure of CD38 and the structures of its various substrate complexes have now been determined, clarifying the mechanism of its multifunctional catalysis. We anticipate that these advances will lead to the unmasking of all the key components of the Ca2+ signaling pathway mediated by NAADP.
Collapse
Affiliation(s)
- Andreas H Guse
- The Calcium Signaling Group, Institute of Biochemistry and Molecular Biology I, Cellular Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20146 Hamburg, Germany.
| | | |
Collapse
|
14
|
Identification of an unusual AT(D)Pase-like activity in multifunctional NAD glycohydrolase from the venom of Agkistrodon acutus. Biochimie 2008; 91:240-51. [PMID: 18952139 DOI: 10.1016/j.biochi.2008.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 09/24/2008] [Indexed: 11/22/2022]
Abstract
NAD-glycohydrolases (NADases) are ubiquitous enzymes that possess NAD glycohydrolase, ADPR cyclase or cADPR hydrolase activity. All these activities are attributed to the NADase-catalyzed cleavage of C-N glycosyl bond. AA-NADase purified from the venom of Agkistrodon acutus is different from the known NADases, for it consists of two chains linked with disulfide-bond(s) and contains one Cu(2+) ion. Here, we show that AA-NADase is not only able to cleave the C-N glycosyl bond of NAD to produce ADPR and nicotinamide, but also able to cleave the phosphoanhydride linkages of ATP, ADP and AMP-PNP to yield AMP. AA-NADase selectively cleaves the P-O-P bond of ATP, ADP and AMP-PNP without the cleavage of P-O-P bond of NAD. The hydrolysis reactions of NAD, ATP and ADP catalyzed by AA-NADase are mutually competitive. ATP is the excellent substrate for AA-NADase with the highest specificity constant k(cat)/K(m) of 293+/-7mM(-1)s(-1). AA-NADase catalyzes the hydrolysis of ATP to produce AMP with an intermediate ADP. AA-NADase binds with one AMP with high affinity determined by isothermal titration calorimetry (ITC). AMP is an efficient inhibitor against NAD. AA-NADase has so far been identified as the first unique multicatalytic enzyme with both NADase and AT(D)Pase-like activities.
Collapse
|
15
|
Gambara G, Billington RA, Debidda M, D'Alessio A, Palombi F, Ziparo E, Genazzani AA, Filippini A. NAADP-induced Ca(2+ signaling in response to endothelin is via the receptor subtype B and requires the integrity of lipid rafts/caveolae. J Cell Physiol 2008; 216:396-404. [PMID: 18288637 DOI: 10.1002/jcp.21407] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have investigated the role of NAADP-mediated Ca(2+) mobilization in endothelin (ET) signaling via endothelin receptor subtype A (ETA) and endothelin receptor subtype B (ETB) in rat peritubular smooth muscle cells. Microinjection and extracellular application of NAADP were both able to elicit Ca(2+) release which was blocked by inhibitory concentrations of NAADP, by impairing Ca(2+) uptake in acidic stores with bafilomycin, and by thapsigargin. Ca(2+) release in response to selective ETB stimulation was abolished by inhibition of NAADP signaling through the same strategies, while these treatments only partially impaired ETA-dependent Ca(2+) signaling, showing that transduction of the ETB signal is dependent on NAADP. In addition, we show that lipid rafts/caveolae contain ETA, ETB, and NAADP/cADPR generating enzyme CD38 and that stimulation of ETB receptors results in increased CD38 activity; interestingly, ETB- (but not ETA-) mediated Ca(2+) responses were antagonized by disruption of lipid rafts/caveolae with methyl-beta-cyclodextrin. These data demonstrate a primary role of NAADP in ETB-mediated Ca(2+) signaling and strongly suggest a novel role of lipid rafts/caveolae in triggering ET-induced NAADP signaling.
Collapse
Affiliation(s)
- Guido Gambara
- Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Histology and Medical Embryology, University of Rome La Sapienza, Rome, Italy
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
NAADP (nicotinic acid-adenine dinucleotide phosphate), the most potent Ca2+-mobilizing second messenger, is active in a wide range of organisms and cell types. Until now, all NAADP-producing enzymes have been thought to be members of the ADP-ribosyl cyclase family. ADP-ribosyl cyclases exhibit promiscuous substrate selectivity, synthesize a variety of products and are regulated in a limited manner, which may be non-physiological. In the present paper, we report the presence of an enzyme on the surface of sea urchin sperm that exhibits bell-shaped regulation by Ca2+ over a range (EC(50) of 10 nM and IC(50) of 50 microM) that is physiologically relevant. Uniquely, this surface enzyme possesses complete selectivity for nucleotides with a 2'-phosphate group and exhibits only base-exchange activity without any detectable cyclase activity. Taken together, these findings indicate that this novel enzyme should be considered as the first true NAADP synthase.
Collapse
|
17
|
Vanderauwera S, De Block M, Van de Steene N, van de Cotte B, Metzlaff M, Van Breusegem F. Silencing of poly(ADP-ribose) polymerase in plants alters abiotic stress signal transduction. Proc Natl Acad Sci U S A 2007; 104:15150-5. [PMID: 17823244 PMCID: PMC1986628 DOI: 10.1073/pnas.0706668104] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Indexed: 01/03/2023] Open
Abstract
Transgenic plants with reduced poly(ADP-ribose) polymerase (PARP) levels have broad-spectrum stress-resistant phenotypes. Both Arabidopsis thaliana and oilseed rape (Brassica napus) lines overexpressing RNA interference-PARP constructs were more resistant to various abiotic stress treatments in laboratory and greenhouse experiments without negative effects on growth, development, and seed production. This outperforming stress tolerance was initially attributed solely to a maintained energy homeostasis due to reduced NAD(+) consumption. We show that in PARP2-deficient Arabidopsis plants, the observed abiotic stress resistance can also be explained by alterations in abscisic acid levels that facilitate the induction of a wide set of defense-related genes.
Collapse
Affiliation(s)
- Sandy Vanderauwera
- *Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Technologiepark 927, 9052 Ghent, Belgium
- Department of Molecular Genetics, Ghent University, 9052 Ghent, Belgium; and
| | - Marc De Block
- Bayer BioScience N.V., Technologiepark 38, 9052 Ghent, Belgium
| | | | - Brigitte van de Cotte
- *Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Technologiepark 927, 9052 Ghent, Belgium
- Department of Molecular Genetics, Ghent University, 9052 Ghent, Belgium; and
| | | | - Frank Van Breusegem
- *Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Technologiepark 927, 9052 Ghent, Belgium
- Department of Molecular Genetics, Ghent University, 9052 Ghent, Belgium; and
| |
Collapse
|
18
|
Abstract
CD38 is a novel multifunctional protein that serves not only as an antigen but also as an enzyme. It catalyzes the metabolism of cyclic ADP-ribose and nicotinic acid adenine dinucleotide phosphate, two structurally and functionally distinct Ca(2+) messengers targeting, respectively, the endoplasmic reticulum and lysosomal Ca(2+) stores. The protein has recently been crystallized and its three-dimensional structure solved to a resolution of 1.9 A. The crystal structure of a binary complex reveals critical interactions between residues at the active site and a bound substrate, providing mechanistic insights to its novel multi-functional catalysis. This article reviews the current advances in the understanding of the structural determinants that control the multiple enzymatic reactions catalyzed by CD38.
Collapse
Affiliation(s)
- Hon Cheung Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA.
| |
Collapse
|
19
|
Lee HC. Structure and enzymatic functions of human CD38. MOLECULAR MEDICINE (CAMBRIDGE, MASS.) 2007; 12:317-23. [PMID: 17380198 PMCID: PMC1829193 DOI: 10.2119/2006–00086.lee] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/08/2006] [Accepted: 12/07/2006] [Indexed: 12/12/2022]
Abstract
CD38 is a novel multifunctional protein that serves not only as an antigen but also as an enzyme. It catalyzes the metabolism of cyclic ADP-ribose and nicotinic acid adenine dinucleotide phosphate, two structurally and functionally distinct Ca(2+) messengers targeting, respectively, the endoplasmic reticulum and lysosomal Ca(2+) stores. The protein has recently been crystallized and its three-dimensional structure solved to a resolution of 1.9 A. The crystal structure of a binary complex reveals critical interactions between residues at the active site and a bound substrate, providing mechanistic insights to its novel multi-functional catalysis. This article reviews the current advances in the understanding of the structural determinants that control the multiple enzymatic reactions catalyzed by CD38.
Collapse
Affiliation(s)
- Hon Cheung Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA.
| |
Collapse
|
20
|
Abstract
Cyclic ADP-ribose (cADPR) is a novel Ca(2+) mobilizing second messenger, which is capable of inducing Ca(2+) release from the sarcoplasmic reticulum (SR) via activation of ryanodine receptors (RyR) in vascular cells. This signaling nucleotide has also been reported to participate in generation or modulation of intracellular Ca(2+) sparks, Ca(2+) waves or oscillations, Ca(2+)- induced Ca(2+) release (CICR) and spontaneous transient outward currents (STOCs) in vascular smooth muscle cells (VSMCs). With respect to the role of cADPR-mediated signaling in mediation of vascular responses to different stimuli, there is accumulating evidence showing that cADPR is importantly involved in the Ca(2+) response of vascular endothelial cells (ECs) and VSMCs to various chemical factors such as vasoactive agonists acetylcholine, oxotremorine, endothelin, and physical stimuli such as stretch, electrical depolarization and sheer stress. This cADPR-RyR-mediated Ca(2+) signaling is now recognized as a fundamental mechanism regulating vascular function. Here we reviewed the literature regarding this cADPR signaling pathway in vascular cells with a major focus on the production of cADPR and its physiological roles in the control of vascular tone and vasomotor response. We also summarized some publish results that unveil the underlying mechanisms mediating the actions of cADPR in vascular cells. Given the importance of Ca(2+) in the regulation of vascular function, the results summarized in this brief review will provide new insights into vascular physiology and circulatory regulation.
Collapse
Affiliation(s)
- Andrew Y Zhang
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth UniversityVA, USA
| | - Pin - Lan Li
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth UniversityVA, USA
- * Correspondence to: Pin-Lan LI, M.D, Ph.D. Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, 410 N 12th, Richmond, VA 23298, USA. Tel.: (804) 828-4793; Fax: (804) 828-2117 E-mail:
| |
Collapse
|
21
|
Yen A. Retinoic acid therapy served by ligands cross linking and masking CD38. Leuk Res 2006; 31:423-5. [PMID: 16914201 DOI: 10.1016/j.leukres.2006.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 06/30/2006] [Accepted: 07/10/2006] [Indexed: 11/18/2022]
|
22
|
Billington RA, Harper C, Bellomo EA, Publicover S, Barratt CLR, Genazzani AA. Characterization of cyclic adenine dinucleotide phosphate ribose levels in human spermatozoa. Fertil Steril 2006; 86:891-8. [PMID: 16904113 DOI: 10.1016/j.fertnstert.2006.03.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 03/03/2006] [Accepted: 03/03/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To determine the presence of the Ca2+-releasing pyridine nucleotide derivative, cyclic adenine dinucleotide phosphate ribose (cADPR), in human spermatozoa and to investigate its role in progesterone-induced Ca2+ oscillations in spermatozoa. DESIGN Biochemical investigation on human spermatozoa from healthy volunteers. SETTING Healthy volunteers in an academic research environment. PATIENT(S) Ten volunteers. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) The cADPR levels. RESULT(S) Human spermatozoa contain micromolar concentrations of cADPR that do not change significantly during sperm capacitation. An active synthetic machinery for cADPR is present in human spermatozoa, whereas degradation activity is minimal. Although progesterone-induced Ca2+ oscillations are dependent on the ryanodine receptor, they are unaffected by cADPR antagonists. CONCLUSION(S) It appears that cADPR does not to play a role in Ca2+ oscillations in spermatozoa, but the presence of high concentrations of cADPR suggests that, instead, it may be introduced into the egg at fertilization and play a role in the Ca2+ transient immediately following sperm-egg fusion.
Collapse
|
23
|
Pagadigorria CLS, Marcon F, Kelmer-Bracht AM, Bracht A, Ishii-Iwamoto EL. Effects of methotrexate on calcium flux in rat liver mitochondria, microsomes and plasma membrane vesicles. Comp Biochem Physiol C Toxicol Pharmacol 2006; 143:340-8. [PMID: 16730477 DOI: 10.1016/j.cbpc.2006.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Revised: 03/25/2006] [Accepted: 03/26/2006] [Indexed: 11/30/2022]
Abstract
The metabolic effects of methotrexate in perfused livers are similar to those exerted by hormones acting through Ca(2+)-dependent mechanisms. The aim of the present study was to determine whether the effects of methotrexate are mediated by a direct action on cellular Ca(2+) fluxes. Methotrexate did not affect the ATP-dependent (45)Ca(2+) uptake by mitochondria, microsomes and inside-out plasma membrane vesicles and Ca(2+) efflux from plasma membrane vesicles. However, methotrexate was able to stimulate (45)Ca(2+) release from preloaded microsomes. The amount of Ca(2+) released by methotrexate was similar to that induced by IP(3). Methotrexate could be acting through the capacitative calcium entry mechanism.
Collapse
Affiliation(s)
- Clairce L S Pagadigorria
- Laboratory of Biological Oxidations, Department of Biochemistry, University of Maringá, 87020900 Maringá, Brazil
| | | | | | | | | |
Collapse
|
24
|
Kim DH, Hee SQ, Norris AJ, Faull KF, Eckhert CD. Boric acid inhibits adenosine diphosphate-ribosyl cyclase non-competitively. J Chromatogr A 2006; 1115:246-52. [PMID: 16545389 DOI: 10.1016/j.chroma.2006.02.066] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 02/15/2006] [Accepted: 02/21/2006] [Indexed: 11/20/2022]
Abstract
Adenosine diphosphate-ribosyl cyclase (ADP-ribosyl cyclase) is a ubiquitous enzyme in eukaryotes that converts NAD+ to cyclic-ADP-ribose (cADPR) and nicotinamide. A quantitative assay for cADPR was developed using capillary electrophoresis to separate NAD+, cADPR, ADP-ribose, and ADP with UV detection (254 nm). Using this assay, the apparent Km and Vmax for Aplysia ADP-ribosyl cyclase were determined to be 1.24+/-0.05 mM and 131.8+/-2.0 microM/min, respectively. Boric acid inhibited ADP-ribosyl cyclase non-competitively with a Ki of 40.5+/-0.5 mM. Boric acid binding to cADPR, determined by electrospray ionization mass spectrometry, was characterized by an apparent binding constant, KA, of 655+/-99 L/mol at pH 10.3.
Collapse
Affiliation(s)
- Danny H Kim
- Department of Environmental Health Sciences, Box 951772, University of California, 650 Charles E Young Dr South, Los Angeles, CA 90095-1772, USA
| | | | | | | | | |
Collapse
|
25
|
Plattner H, Kissmehl R. Molecular aspects of rapid, reversible, Ca2+-dependent de-phosphorylation of pp63/parafusin during stimulated exo-endocytosis in Paramecium cells. Cell Calcium 2005; 38:319-27. [PMID: 16102820 DOI: 10.1016/j.ceca.2005.06.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 06/28/2005] [Indexed: 11/16/2022]
Abstract
Ca2+ signalling governs stimulated exocytosis and exocytosis-coupled endocytosis also in Paramecium cells. Upon stimulation, the < or =10(3) dense-core exocytotic organelles (trichocysts) can be synchronously (80 ms) released, followed by endocytotic membrane resealing (350 ms) and retrieval. Paramecium is the most synchronous dense-core exocytotic system known, allowing to dissect rapidly reversible Ca2+-dependent phenomena. This holds for the reversible de-/re-phosphorylation cycle of a 63 kD phosphoprotein, pp63/parafusin (pf), which we have cloned, immuno-localised, and characterised as phosphoglucomutase, the enzyme funneling glucose into the glycolytic pathway. It was isolated ex vivo, followed by MALDI analysis, while X-ray structure analysis was performed after heterologous expression. We found multiple phosphorylation of superficial Ser/Thr residues. Although present also in exo(-) mutants, pp63/pf is selectively de-phosphorylated only in exo(+) strains during synchronous exocytosis (80 ms) and re-phosphorylated within approximately 20 s, i.e., the time required to re-establish [Ca2+] homeostasis. We have isolated relevant protein phosphatases and kinases and probed their activity on pp63/pf in vitro. We consider Ca2+/calmodulin-activated PP2B (calcineurin, whose subunits have been cloned) relevant for de-phosphorylation. Re-phosphorylation can be achieved by two protein kinases that also have been cloned. One is activated by cGMP (PKG) which in turn is formed by Ca2+-activated guanylate cyclase. Another kinase, casein kinase 2, is inhibited by Ca2+ and, hence, activated with some delay in parallel to decreasing [Ca2+] after exocytosis. In total, several Ca2+-sensitive cycles cooperate whose protein components have been localised to the cell cortex. Regulation of the phosphorylation degree of pp63/pf may affect structure binding on a microscale and/or its enzymatic activity. All this may serve fueling substrate into glycolysis with increased ATP re-formation (compromised in exo(-) mutants) and NADH formation, with effects on Ca2+ signalling including mobilisation from cortical stores (alveolar sacs) and overall effects on ATP and Ca2+ dynamics during synchronous exo- and endocytosis.
Collapse
Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, P.O. Box 5560, 78457 Konstanz, Germany.
| | | |
Collapse
|
26
|
Bai N, Lee HC, Laher I. Emerging role of cyclic ADP-ribose (cADPR) in smooth muscle. Pharmacol Ther 2004; 105:189-207. [PMID: 15670626 DOI: 10.1016/j.pharmthera.2004.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 10/14/2004] [Indexed: 10/26/2022]
Abstract
Cyclic adenosine diphosphate ribose (cADPR) is a naturally occurring cyclic nucleotide and represents a novel class of endogenous Ca(2+) messengers implicated in the regulation of the gating properties of ryanodine receptors (RyRs). This action of cADPR occurs independently from the inositol-1,4,5-trisphosphate (IP(3)) receptor. The regulation of intracellular Ca(2+) release is a fundamental element of cellular Ca(2+) homeostasis since a number of smooth muscle functions (tone, proliferation, apoptosis, and gene expression) are modulated by intracellular Ca(2+) concentration ([Ca(2+)](i)). There has been a surge in the efforts aimed at understanding the mechanisms of cADPR-mediated Ca(2+) mobilization and its impact on smooth muscle function. This review summarizes the proposed roles of cADPR in the regulation of smooth muscle tone.
Collapse
Affiliation(s)
- Ni Bai
- Department of Pharmacology and Therapeutics, University of British Columbia Vancouver, BC, Canada V6T 1Z3
| | | | | |
Collapse
|
27
|
Li PL, Lee HC, Nelson MT, Meininger GA, Van Breemen C. Novel Ca2+ signalling mechanisms in vascular myocytes: symposium overview. ACTA ACUST UNITED AC 2004; 179:339-52. [PMID: 14656371 DOI: 10.1046/j.0001-6772.2003.01216.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This commentary presents the proceedings of the symposium sponsored by Cardiovascular Section of American Physiological Society in San Diego, CA on 12 April 2003. The major focus of this symposium was on the actions and physiological relevance of several novel Ca2+ signalling mechanisms in vascular smooth muscle (VSM) cells. Five important topics were presented in this symposium including the discovery and roles of cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP) in mediating Ca2+ release, Ca2+ sparks and activation of plasma membrane KCa channels in VSM cells, the role of cADPR-mediated activation of ryanodine receptors in the control of vascular tone, the role of [Ca2+]i in mechanotransduction in the arterioles, and interactions of mitochondrial Ca2+ release and SR Ca2+ mobilization. The purpose of this symposium was to promote discussions and exchange of ideas between scientists with interests in Ca2+ signalling mechanisms and those with interests in vascular physiology and pharmacology. The cross-fertilization of ideas is expected to greatly advance our understanding of the physiological and pharmacological relevance of these new Ca2+ signalling mechanisms.
Collapse
Affiliation(s)
- P-L Li
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | | | | | | | | |
Collapse
|
28
|
Lacapère JJ, Boulla G, Lund FE, Primack J, Oppenheimer N, Schuber F, Deterre P. Fluorometric studies of ligand-induced conformational changes of CD38. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2003; 1652:17-26. [PMID: 14580993 DOI: 10.1016/j.bbapap.2003.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The lymphoid surface antigen CD38 is a NAD(+)-glycohydrolase that also catalyzes the transformation of NAD(+) into cyclic ADP-ribose, a calcium mobilizing second messenger. In addition, ligation of CD38 by antibodies triggers signaling in lymphoid cells. Since the cytoplasmic tail of CD38 is dispensable for this latter property, we have previously proposed that CD38-mediated receptor signal transduction might be regulated by its conformational state. We have now examined the molecular changes of this protein during its interaction with NAD(+) by measuring the intrinsic fluorescence of CD38. We have shown that addition of the substrate produced a dramatic decrease in the fluorescence of the catalytically active recombinant soluble ectodomain of murine CD38. Analysis of this event revealed that the catalytic cycle involves a state of the enzyme that is characterized by a low fluorescence which, upon substrate turnover, reverts to the initial high intrinsic fluorescence level. In contrast, non-hydrolyzable substrates trap CD38 in its altered low fluorescence state. Studies with the hydrophilic quencher potassium iodide revealed that the tryptophan residues that are mainly involved in the observed changes in fluorescence, are remote from the active site. Similar data were also obtained with human CD38, indicating that studies of intrinsic fluorescence will be useful in monitoring the transconformation of CD38 from different species. Together, these data demonstrate that CD38 undergoes a reversible conformational change after substrate binding, and suggest a mechanism by which this change could alter interactions with different cell-surface partners.
Collapse
Affiliation(s)
- Jean-Jacques Lacapère
- INSERM U410, Faculté de Médecine Xavier Bichat, 16 rue Henri Huchard, 75018 Paris, France
| | | | | | | | | | | | | |
Collapse
|
29
|
Mitchell KJ, Lai FA, Rutter GA. Ryanodine receptor type I and nicotinic acid adenine dinucleotide phosphate receptors mediate Ca2+ release from insulin-containing vesicles in living pancreatic beta-cells (MIN6). J Biol Chem 2003; 278:11057-64. [PMID: 12538591 DOI: 10.1074/jbc.m210257200] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have demonstrated recently (Mitchell, K. J., Pinton, P., Varadi, A., Tacchetti, C., Ainscow, E. K., Pozzan, T., Rizzuto, R., and Rutter, G. A. (2001) J. Cell Biol. 155, 41-51) that ryanodine receptors (RyR) are present on insulin-containing secretory vesicles. Here we show that pancreatic islets and derived beta-cell lines express type I and II, but not type III, RyRs. Purified by subcellular fractionation and membrane immuno-isolation, dense core secretory vesicles were found to possess a similar level of type I RyR immunoreactivity as Golgi/endoplasmic reticulum (ER) membranes but substantially less RyR II than the latter. Monitored in cells expressing appropriately targeted aequorins, dantrolene, an inhibitor of RyR I channels, elevated free Ca(2+) concentrations in the secretory vesicle compartment from 40.1 +/- 6.7 to 90.4 +/- 14.8 microm (n = 4, p < 0.01), while having no effect on ER Ca(2+) concentrations. Furthermore, nicotinic acid adenine dinucleotide phosphate (NAADP), a novel Ca(2+)-mobilizing agent, decreased dense core secretory vesicle but not ER free Ca(2+) concentrations in permeabilized MIN6 beta-cells, and flash photolysis of caged NAADP released Ca(2+) from a thapsigargin-insensitive Ca(2+) store in single MIN6 cells. Because dantrolene strongly inhibited glucose-stimulated insulin secretion (from 3.07 +/- 0.51-fold stimulation to no significant glucose effect; n = 3, p < 0.01), we conclude that RyR I-mediated Ca(2+)-induced Ca(2+) release from secretory vesicles, possibly potentiated by NAADP, is essential for the activation of insulin secretion.
Collapse
Affiliation(s)
- Kathryn J Mitchell
- Henry Wellcome Laboratories of Integrated Cell Signaling and Department of Biochemistry, School of Medical Sciences, University Walk, University of Bristol, Bristol BS8 1TD, United Kingdom
| | | | | |
Collapse
|
30
|
Munshi CB, Graeff R, Lee HC. Evidence for a causal role of CD38 expression in granulocytic differentiation of human HL-60 cells. J Biol Chem 2002; 277:49453-8. [PMID: 12386160 DOI: 10.1074/jbc.m209313200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Granulocytic differentiation of human HL-60 cells can be induced by retinoic acid and is accompanied by a massive expression of CD38, a multi-functional enzyme responsible for metabolizing cyclic ADP-ribose (cADPR), a Ca(2+) messenger. Immunofluorescence staining showed that CD38 was expressed not only on the surface of intact HL-60 cells but also intracellularly, which was revealed after permeabilization with Triton. Concomitant with CD38 expression was the accumulation of cADPR, and both time courses preceded the onset of differentiation, suggesting a causal role for CD38. Consistently, treatment of HL-60 cells with a permeant inhibitor of CD38, nicotinamide, inhibited both the CD38 activity and differentiation. More specific blockage of CD38 expression was achieved by using morpholino antisense oligonucleotides targeting its mRNA, which produced a corresponding inhibition of differentiation as well. Similar inhibitory effects were observed when CD38 expression was reduced by the RNA interference technique targeting two separate regions of the coding sequence of CD38. Further support came from transfecting HL-60 cells with a Tet-On expression vector containing a full-length CD38. Subsequent treatments with doxycycline induced both CD38 expression and differentiation in the absence of retinoic acid. These results provide the first evidence that CD38 expression and the consequential accumulation of cADPR play a causal role in mediating cellular differentiation.
Collapse
Affiliation(s)
- Cyrus B Munshi
- Department of Pharmacology, University of Minnesota, 321 Church Street, Minneapolis, MN 55455, USA
| | | | | |
Collapse
|
31
|
Graeff R, Lee HC. A novel cycling assay for nicotinic acid-adenine dinucleotide phosphate with nanomolar sensitivity. Biochem J 2002; 367:163-8. [PMID: 12117413 PMCID: PMC1222877 DOI: 10.1042/bj20020644] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2002] [Revised: 06/21/2002] [Accepted: 07/15/2002] [Indexed: 11/17/2022]
Abstract
Nicotinic acid-adenine dinucleotide phosphate (NAADP) is a novel nucleotide derived from NADP that has now been shown to be active in releasing Ca(2+) from intracellular stores in a wide variety of cells ranging from plant to human. Despite the obvious importance of monitoring its cellular levels under various physiological conditions, no assay has been reported for NAADP to date. In the present study, a widely applicable assay for NAADP with high sensitivity is described. NAADP was first dephosphorylated to nicotinic acid-adenine dinucleotide by treatment with alkaline phosphatase. The conversion was shown to be stoichiometric. NMN-adenylyltransferase was then used to convert nicotinic acid-adenine dinucleotide into NAD in the presence of high concentrations of NMN. The resultant NAD was amplified by a cycling assay involving alcohol dehydrogenase and diaphorase. Each time NAD cycled through these coupled reactions, a molecule of highly fluorescent resorufin was generated. The reaction could be performed for hours, resulting in more than a 1000-fold amplification. Concentrations of NAADP over the 10-20 nM range could be routinely measured. This novel cycling assay was combined with an enzymic treatment to provide the necessary specificity for the assay. NAADP was found to be resistant to NADase and apyrase. Pretreatment of samples with a combination of the hydrolytic enzymes completely eliminated the interference from common nucleotides. The versatility of the cycling assay can also be extended to measure nicotinic acid, which is a substrate in the synthesis of NAADP catalysed by ADP-ribosyl cyclase, over the micromolar range. All the necessary reagents for the cycling assay are widely available and it can be performed using a multi-well fluorescence plate reader, providing a high-throughput method. This is the first assay reported for NAADP and nicotinic acid, which should be valuable in elucidating the messenger functions of NAADP.
Collapse
Affiliation(s)
- Richard Graeff
- Department of Pharmacology, 321 Church Street SE, 4-145 Jackson Hall, University of Minnesota, Minneapolis, MN 55455, U.S.A
| | | |
Collapse
|
32
|
Abstract
Recently, nicotinic acid adenine dinucleotide phosphate (NAADP) has been shown, using different techniques, to mobilize intracellular Ca2+ stores in invertebrate, lower vertebrate, plant and mammalian cells. This endogenous molecule might play an atypical role in Ca2+ signalling by coordinating the responses of other Ca2+-releasing messengers. Furthermore, radioligand binding experiments have provided an insight into how desensitization of the NAADP receptor might occur.
Collapse
Affiliation(s)
- Armando A Genazzani
- Dept of Pharmacology, University of Cambridge, Tennis Court Road, CB2 1PD, Cambridge, UK.
| | | |
Collapse
|
33
|
Chini EN, Chini CCS, Kato I, Takasawa S, Okamoto H. CD38 is the major enzyme responsible for synthesis of nicotinic acid-adenine dinucleotide phosphate in mammalian tissues. Biochem J 2002; 362:125-30. [PMID: 11829748 PMCID: PMC1222368 DOI: 10.1042/0264-6021:3620125] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the present study, we have determined the role of the enzyme CD38 upon the synthesis of the Ca(2+)-releasing nucleotide nicotinic acid-adenine dinucleotide phosphate (NAADP). In rat tissues, we observed that the capacity for NAADP synthesis could be co-immunoprecipitated with CD38 using an anti-CD38 antibody. Furthermore, we observed that several tissues from CD38 knockout mice had no capacity for the synthesis of this nucleotide. In addition, CD38 was also identified as the major enzyme responsible for the synthesis of the second messenger cyclic ADP-ribose. These observations lead to the conclusion that CD38 is the major enzyme responsible for the synthesis of NAADP and cyclic ADP-ribose, and raises the possibility of a new signalling pathway where two different Ca(2+)-releasing nucleotides are synthesized by the same enzyme.
Collapse
Affiliation(s)
- Eduardo N Chini
- Department of Anesthesia, Mayo Clinic and Foundation, 200 First Street, Rochester, MN 55905, U.S.A.
| | | | | | | | | |
Collapse
|
34
|
Schweitzer K, Mayr GW, Guse AH. Assay for ADP-ribosyl cyclase by reverse-phase high-performance liquid chromatography. Anal Biochem 2001; 299:218-26. [PMID: 11730346 DOI: 10.1006/abio.2001.5419] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cyclic ADP-ribose (cADPR), a natural metabolite of beta-NAD(+), is a second messenger for Ca(2+) signaling in T cells. As a tool for purification and identification of ADP-ribosyl cyclase(s) in T cells, a sensitive and specific enzymatic assay using 1,N(6)-etheno-NAD(+) as substrate was developed. A major problem-the sensitivity of 1,N(6)-etheno-cADPR toward the extraction medium perchloric acid-was solved by replacing the perchloric acid extraction procedure of nucleotides by a filtration step. Standard compounds for the HPLC analysis of ADP-ribosyl cyclases and NAD(+)-glycohydrolases, e.g., 1,N(6)-etheno-cADPR, 1,N(6)-etheno-ADPR, and 1,N(6)-etheno-AMP, were produced by ADP-ribosyl cyclase from Aplysia californica and dinucleotide pyrophosphatase. The assay was applied to subcellular fractions prepared from human Jurkat T cells. As a result ADP-ribosyl cyclase and NAD(+)-glycohydrolase activity could be detected and precisely quantified in different subcellular fractions indicating the presence of different isoenzymes in T cells.
Collapse
Affiliation(s)
- K Schweitzer
- University Hospital Hamburg-Eppendorf, Institute for Medical Biochemistry and Molecular Biology, Division of Cellular Signal Transduction, University of Hamburg, Martinistrasse 52, D-20246 Hamburg, Germany
| | | | | |
Collapse
|
35
|
Gillingwater TH, Ribchester RR. Compartmental neurodegeneration and synaptic plasticity in the Wld(s) mutant mouse. J Physiol 2001; 534:627-39. [PMID: 11483696 PMCID: PMC2278742 DOI: 10.1111/j.1469-7793.2001.00627.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2001] [Accepted: 06/04/2001] [Indexed: 12/13/2022] Open
Abstract
This review focuses on recent developments in our understanding of neurodegeneration at the mammalian neuromuscular junction. We provide evidence to support a hypothesis of compartmental neurodegeneration, whereby synaptic degeneration occurs by a separate, distinct mechanism from cell body and axonal degeneration. Studies of the spontaneous mutant Wld(s) mouse, in which Wallerian degeneration is characteristically slow, provide key evidence in support of this hypothesis. Some features of synaptic degeneration in the absence of Wallerian degeneration resemble synapse elimination in neonatal muscle. This and other forms of synaptic plasticity may be accessible to further investigations, exploiting advantages afforded by the Wld(s) mutant, or transgenic mice that express the Wld(s) gene.
Collapse
Affiliation(s)
- T H Gillingwater
- Department of Neuroscience, University of Edinburgh, Edinburgh EH8 9JZ, UK
| | | |
Collapse
|
36
|
Abstract
Cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP) are two Ca(2+) messengers derived from NAD and NADP, respectively. Although NAADP is a linear molecule, structurally distinct from the cyclic cADPR, it is synthesized by similar enzymes, ADP-ribosyl cyclase and its homolog, CD38. The crystal structure of the cyclase has been solved and its active site identified. These two novel nucleotides have now been shown to be involved in a wide range of cellular functions including: cell cycle regulation in Euglena, a protist; gene expression in plants; and in animal systems, from fertilization to neurotransmitter release and long-term depression in brain. A battery of pharmacological reagents have been developed, providing valuable tools for elucidating the physiological functions of these two novel Ca(2+) messengers. This article reviews these recent results and explores the implications of the existence of multiple Ca(2+) messengers and Ca(2+) stores in cells.
Collapse
Affiliation(s)
- H C Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
| |
Collapse
|
37
|
Begley TP, Kinsland C, Mehl RA, Osterman A, Dorrestein P. The biosynthesis of nicotinamide adenine dinucleotides in bacteria. VITAMINS AND HORMONES 2001; 61:103-19. [PMID: 11153263 DOI: 10.1016/s0083-6729(01)61003-3] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The nicotinamide adenine dinucleotides (NAD, NADH, NADP, and NADPH) are essential cofactors in all living systems and function as hydride acceptors (NAD, NADP) and hydride donors (NADH, NADPH) in biochemical redox reactions. The six-step bacterial biosynthetic pathway begins with the oxidation of aspartate to iminosuccinic acid, which is then condensed with dihydroxyacetone phosphate to give quinolinic acid. Phosphoribosylation and decarboxylation of quinolinic acid gives nicotinic acid mononucleotide. Adenylation of this mononucleotide followed by amide formation completes the biosynthesis of NAD. An additional phosphorylation gives NADP. This review focuses on the mechanistic enzymology of this pathway in bacteria.
Collapse
Affiliation(s)
- T P Begley
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | | | | | | | | |
Collapse
|
38
|
Navazio L, Mariani P, Sanders D. Mobilization of Ca2+ by cyclic ADP-ribose from the endoplasmic reticulum of cauliflower florets. PLANT PHYSIOLOGY 2001; 125:2129-38. [PMID: 11299392 PMCID: PMC88868 DOI: 10.1104/pp.125.4.2129] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2000] [Accepted: 01/10/2001] [Indexed: 05/18/2023]
Abstract
The NAD+ metabolite cADP-Rib (cADPR) elevates cytosolic free Ca2+ in plants and thereby plays a central role in signal transduction pathways evoked by the drought and stress hormone abscisic acid. cADPR is known to mobilize Ca2+ from the large vacuole of mature cells. To determine whether additional sites for cADPR-gated Ca2+ release reside in plant cells, microsomes from cauliflower (Brassica oleracea) inflorescences were subfractionated on sucrose density gradients, and the distribution of cADPR-elicited Ca2+ release was monitored. cADPR-gated Ca2+ release was detected in the heavy-density fractions associated with rough endoplasmic reticulum (ER). cADPR-dependent Ca2+ release co-migrated with two ER markers, calnexin and antimycin A-insensitive NADH-cytochrome c reductase activity. To investigate the possibility that contaminating plasma membrane in the ER-rich fractions was responsible for the observed release, plasma membrane vesicles were purified by aqueous two-phase partitioning, everted with Brij-58, and loaded with Ca2+: These vesicles failed to respond to cADPR. Ca2+ release evoked by cADPR at the ER was fully inhibited by ruthenium red and 8-NH2-cADPR, a specific antagonist of cADPR-gated Ca2+ release in animal cells. The presence of a Ca2+ release pathway activated by cADPR at higher plant ER reinforces the notion that, alongside the vacuole, the ER participates in Ca2+ signaling.
Collapse
Affiliation(s)
- L Navazio
- The Plant Laboratory, Department of Biology, University of York, P.O. Box 373, York YO10 5YW, United Kingdom
| | | | | |
Collapse
|
39
|
Plattner H, Klauke N. Calcium in ciliated protozoa: sources, regulation, and calcium-regulated cell functions. INTERNATIONAL REVIEW OF CYTOLOGY 2001; 201:115-208. [PMID: 11057832 DOI: 10.1016/s0074-7696(01)01003-8] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In ciliates, a variety of processes are regulated by Ca2+, e.g., exocytosis, endocytosis, ciliary beat, cell contraction, and nuclear migration. Differential microdomain regulation may occur by activation of specific channels in different cell regions (e.g., voltage-dependent Ca2+ channels in cilia), by local, nonpropagated activation of subplasmalemmal Ca stores (alveolar sacs), by different sensitivity thresholds, and eventually by interplay with additional second messengers (cilia). During stimulus-secretion coupling, Ca2+ as the only known second messenger operates at approximately 5 microM, whereby mobilization from alveolar sacs is superimposed by "store-operated Ca2+ influx" (SOC), to drive exocytotic and endocytotic membrane fusion. (Content discharge requires binding of extracellular Ca2+ to some secretory proteins.) Ca2+ homeostasis is reestablished by binding to cytosolic Ca2+-binding proteins (e.g., calmodulin), by sequestration into mitochondria (perhaps by Ca2+ uniporter) and into endoplasmic reticulum and alveolar sacs (with a SERCA-type pump), and by extrusion via a plasmalemmal Ca2+ pump and a Na+/Ca2+ exchanger. Comparison of free vs total concentration, [Ca2+] vs [Ca], during activation, using time-resolved fluorochrome analysis and X-ray microanalysis, respectively, reveals that altogether activation requires a calcium flux that is orders of magnitude larger than that expected from the [Ca2+] actually required for local activation.
Collapse
Affiliation(s)
- H Plattner
- Department of Biology, University of Konstanz, Germany
| | | |
Collapse
|
40
|
Stabb EV, Reich KA, Ruby EG. Vibrio fischeri genes hvnA and hvnB encode secreted NAD(+)-glycohydrolases. J Bacteriol 2001; 183:309-17. [PMID: 11114931 PMCID: PMC94880 DOI: 10.1128/jb.183.1.309-317.2001] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HvnA and HvnB are proteins secreted by Vibrio fischeri ES114, an extracellular light organ symbiont of the squid Euprymna scolopes, that catalyze the transfer of ADP-ribose from NAD(+) to polyarginine. Based on this activity, HvnA and HvnB were presumptively designated mono-ADP-ribosyltransferases (ARTases), and it was hypothesized that they mediate bacterium-host signaling. We have cloned hvnA and hvnB from strain ES114. hvnA appears to be expressed as part of a four-gene operon, whereas hvnB is monocistronic. The predicted HvnA and HvnB amino acid sequences are 46% identical to one another and share 44% and 34% identity, respectively, with an open reading frame present in the Pseudomonas aeruginosa genome. Four lines of evidence indicate that HvnA and HvnB mediate polyarginine ADP-ribosylation not by ARTase activity, but indirectly through an NAD(+)-glycohydrolase (NADase) activity that releases free, reactive, ADP-ribose: (i) like other NADases, and in contrast to the ARTase cholera toxin, HvnA and HvnB catalyzed ribosylation of not only polyarginine but also polylysine and polyhistidine, and ribosylation was inhibited by hydroxylamine; (ii) HvnA and HvnB cleaved 1, N(6)-etheno-NAD(+) and NAD(+); (iii) incubation of HvnA and HvnB with [(32)P]NAD(+) resulted in the production of ADP-ribose; and (iv) purified HvnA displayed an NADase V(max) of 400 mol min(-1) mol(-1), which is within the range reported for other NADases and 10(2)- to 10(4)-fold higher than the minor NADase activity reported in bacterial ARTase toxins. Construction and analysis of an hvnA hvnB mutant revealed no other NADase activity in culture supernatants of V. fischeri, and this mutant initiated the light organ symbiosis and triggered regression of the light organ ciliated epithelium in a manner similar to that for the wild type.
Collapse
Affiliation(s)
- E V Stabb
- Pacific Biomedical Research Center, University of Hawaii, Honolulu, Hawaii 96813, USA.
| | | | | |
Collapse
|
41
|
Munshi C, Aarhus R, Graeff R, Walseth TF, Levitt D, Lee HC. Identification of the enzymatic active site of CD38 by site-directed mutagenesis. J Biol Chem 2000; 275:21566-71. [PMID: 10781610 DOI: 10.1074/jbc.m909365199] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
CD38 is a ubiquitous protein originally identified as a lymphocyte antigen and recently also found to be a multifunctional enzyme participating in the synthesis and metabolism of two Ca(2+) messengers, cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate. It is homologous to Aplysia ADP-ribosyl cyclase, where the crystal structure has been determined. Residues of CD38 corresponding to those at the active site of the Aplysia cyclase were mutagenized. Changing Glu-226, which corresponded to the catalytic residue of the cyclase, to Asp, Asn, Gln, Leu, or Gly eliminated essentially all enzymatic activities of CD38, indicating it is most likely the catalytic residue. Photoaffinity labeling showed that E226G, nevertheless, retained substantial NAD binding activity. The secondary structures of these inactive mutants as measured by circular dichroism were essentially unperturbed as compared with the wild type. Other nearby residues were also investigated. The mutants D147V and E146L showed 7- and 19-fold reduction in NADase activity, respectively. The cADPR hydrolase activity of the two mutants was similarly reduced. Asp-155, on the other hand, was crucial for the GDP-ribosyl cyclase activity since its substitution with either Glu, Asn, or Gln stimulated the activity 3-15-fold, whereas other activities remained essentially unchanged. In addition to these acidic residues, two tryptophans were also important, since all enzyme activities of W125F, W125Y, W189G and W189Y were substantially reduced. This is consistent with the two tryptophans serving a substrate positioning function. A good correlation was observed when the NADase activity of all the mutants was plotted against the cADPR hydrolase activity. Homology modeling revealed all these critical residues are clustered in a pocket near the center of the CD38 molecule. The results indicate a strong structural homology between the active sites of CD38 and the Aplysia cyclase.
Collapse
Affiliation(s)
- C Munshi
- Departments of Pharmacology and Physiology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | | | | | | | | | | |
Collapse
|
42
|
Lee HC. Multiple calcium stores: separate but interacting. SCIENCE'S STKE : SIGNAL TRANSDUCTION KNOWLEDGE ENVIRONMENT 2000; 2000:pe1. [PMID: 11752596 DOI: 10.1126/stke.2000.40.pe1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Multiple mechanisms exist for increasing the concentration of intracellular calcium. This Perspective by Lee is one in a series on intracellular calcium release mechanisms and focuses on the calcium store operated by nicotinic acid adenine dinucleotide phosphate (NAADP). The characterization of the NAADP-operated calcium store as separate from the inositol trisphosphate (IP(3))-operated and cyclic ADP-ribose (cADPR)-operated calcium stores is discussed. Lee also addresses the role of NAADP in regulating intracellular calcium fluctuations during fertilization and hormonal activation of pancreatic acinar cells.
Collapse
Affiliation(s)
- H C Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA.
| |
Collapse
|
43
|
|