title: Is hydrogen ion (H(+)) the real second messenger in calcium signalling?
abstract: Most second messengers have the acknowledged ability to mobilize the segregated Ca(2+) from intracellular stores, although the mechanisms of mobilization are unclear. To study this problem, the fact that inositol 1,4,5-trisphosphate, and six other known endogenous Ca(2+) mobilizers are acids, or acid-generating compounds, is highlighted. In physiological conditions, a newly generated acid releases H(+). The transient rise of H(+) in the cytosol may induce the lowering of pH, mobilization of bound Ca(2+), protein conformational rearrangement, store depletion, and Ca(2+) influx. Accordingly, a new description of the basic mechanism for signal transduction in non-excitable cells and the related consequences is put forward.
authors.affiliation: Biochemical Specialist at Molinari Giuliano, Via Agrigento 56, 37138 Verona Italy. Electronic address: giuliano.molinari@fastwebnet.it.
authors.forename: Giuliano
authors.initials: G
authors.lastname: Molinari
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D020013:Calcium Signaling; D000242:Cyclic AMP / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008246:Lysophospholipids / Q000378:metabolism; D009249:NADP / Q000031:analogs & derivatives / Q000378:metabolism; D015290:Second Messenger Systems; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D008246:Lysophospholipids; C060506:sphingosine 1-phosphate; D009249:NADP; C024376:NAADP; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D013110:Sphingosine
keywords: Ca(2+) mobilizer; Calcium signal; H(+); IP3; Second messenger; Store depletion