Department of Pharmacology, University of Oxford, UK.
Adv Exp Med Biol. 2012;740:305-23. doi: 10.1007/978-94-007-2888-2_13.
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).
钙离子信号可能是最常见的细胞内信号分子，控制着几乎所有细胞中广泛的反应。许多细胞刺激物，通常作用于细胞膜表面受体，通过动员细胞内储存的钙离子来引发钙离子信号。三磷酸肌醇 (IP₃) 是第一个被证明将质膜上的事件与内质网 (ER) 中钙离子释放联系起来的信使，通过激活 IP₃门控钙离子释放通道 (IP₃ 受体)。随后，发现了另外两种钙离子动员信使，环二核苷酸 (cADPR) 和烟酰胺二核苷酸磷酸 (NAADP)。两者都是吡啶核苷酸的代谢产物，可能由同一类酶，即 ADP-核糖基环化酶产生，如 CD38。虽然 cADPR 通过激活肌醇 1,4,5-三磷酸受体 (RyRs) 从 ER 中动员钙离子，但 NAADP 通过涉及激活双孔通道 (TPCs) 的机制从酸性储存库中释放钙离子。
