Nicotinic acid adenine dinucleotide phosphate-induced Ca(2+) release. Interactions among distinct Ca(2+) mobilizing mechanisms in starfish oocytes

J Biol Chem. 2000 Mar 24;275(12):8301-6. doi: 10.1074/jbc.275.12.8301.

Abstract

An intracellular mechanism activated by nicotinic acid adenine dinucleotide phosphate (NAADP(+)) contributes to intracellular Ca(2+) release alongside inositol 1,4,5-trisphosphate (Ins-P(3)) and ryanodine receptors. The NAADP(+)-sensitive mechanism has been shown to be operative in sea urchin eggs, ascidian eggs, and pancreatic acinar cells. Furthermore, most mammalian cell types can synthesize NAADP(+), with nicotinic acid and NADP(+) as precursors. In this contribution, NAADP(+)-induced Ca(2+) release has been investigated in starfish oocytes. Uncaging of injected NAADP(+) induced Ca(2+) mobilization in both immature oocytes and in oocytes matured by the hormone 1-methyladenine (1-MA). The role of extracellular Ca(2+) in NAADP(+)-induced Ca(2+) mobilization, which was minor in immature oocytes, was instead essential in mature oocytes. Thus, the NAADP(+)-sensitive Ca(2+) pool, which is known to be distinct from those sensitive to inositol 1,4,5-trisphosphate or cyclic ADPribose, apparently migrated closer to (or became part of) the plasma membrane during the maturation process. Inhibition of both Ins-P(3) and ryanodine receptors, but not of either alone, substantially inhibited NAADP(+)-induced Ca(2+) mobilization in both immature and mature oocytes. The data also suggest that NAADP(+)-induced Ca(2+) mobilization acted as a trigger for Ca(2+) release via Ins-P(3) and ryanodine receptors.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Age Factors
  • Animals
  • Calcium Channel Blockers / pharmacology
  • Calcium Signaling*
  • NADP / analogs & derivatives*
  • NADP / pharmacology
  • Oocytes / drug effects
  • Oocytes / physiology*
  • Starfish

Substances

  • Calcium Channel Blockers
  • 1-methyladenine
  • NADP
  • NAADP
  • Adenine

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