Nicotinic acid adenine dinucleotide phosphate (NAADP) and Ca2+ mobilization.
Many physiological processes are controlled by a great diversity of Ca2+ signals that depend on Ca2+ entry into the cell and/or Ca2+ release from internal Ca2+ stores. Ca2+ mobilization from intracellular stores is gated by a family of messengers including inositol-1,4,5-trisphosphate (InsP3), cyclic ADP-ribose (cADPR), and nicotinic acid adenine dinucleotide phosphate (NAADP). There is increasing evidence for a novel intracellular Ca2+ release channel that may be targeted by NAADP and that displays properties distinctly different from the well-characterized InsP3 and ryanodine receptors. These channels appear to localize on a wider range of intracellular organelles, including the acidic Ca2+ stores. Activation of the NAADP-sensitive Ca2+ channels evokes complex changes in cytoplasmic Ca2+ levels by means of channel chatter with other intracellular Ca2+ channels. The recent demonstration of changes in intracellular NAADP levels in response to physiologically relevant extracellular stimuli highlights the significance of NAADP as an important regulator of intracellular Ca2+ signaling.
Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary. mickeyka@freemail.hu
Miklós
M
Mándi
Judit
J
Bak
D000818:Animals; D020013:Calcium Signaling; D006801:Humans; D009249:NADP / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D011956:Receptors, Cell Surface / Q000378:metabolism
D011956:Receptors, Cell Surface; D009249:NADP; C024376:NAADP