title: Pyridine nucleotide metabolites and calcium release from intracellular stores.
abstract: Ca(2+) signals are probably the most common intracellular signaling elements, controlling an extensive range of responses in virtually all cells. Many cellular stimuli, often acting at cell surface receptors, evoke Ca(2+) signals by mobilizing Ca(2+) from intracellular stores. Inositol trisphosphate (IP₃) was the first messenger shown to link events at the plasma membrane to release of Ca(2+) from the endoplasmic reticulum (ER), through activation of IP₃-gated Ca(2+) release channels (IP₃ receptors). Subsequently, two additional Ca(2+) mobilizing messengers were discovered, cADPR and NAADP. Both are metabolites of pyridine nucleotides, and may be produced by the same class of enzymes, ADP-ribosyl cyclases, such as CD38. Whilst cADPR mobilizes Ca(2+) from the ER by activation of ryanodine receptors (RyRs), NAADP releases Ca(2+) from acidic stores by a mechanism involving the activation of two pore channels (TPCs).
authors.affiliation: Department of Pharmacology, University of Oxford, UK. antony.galione@pharm.ox.ac.uk
authors.forename: Antony
authors.initials: A
authors.lastname: Galione
authors.forename: Kai-Ting
authors.initials: KT
authors.lastname: Chuang
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D036563:Cyclic ADP-Ribose / Q000502:physiology*; D006801:Humans; D009249:NADP / Q000031:analogs & derivatives* / Q000502:physiology
chemical_list: D036563:Cyclic ADP-Ribose; D009249:NADP; C024376:NAADP; D002118:Calcium