Ca2+ release triggered by nicotinate adenine dinucleotide phosphate in intact sea urchin eggs

C. M. Perez-Terzic, E. N. Chini, S. S. Shen, T. P. Dousa, D. E. Clapham

Research output: Contribution to journalArticle

50 Scopus citations

Abstract

Nicotinate adenine dinucleotide phosphate (NAADP) was recently identified as a potent Ca2+-releasing agent in sea urchin egg homogenates. NAADP triggered Ca2+ release by a mechanism that was distinct from inositol 1,4,5-trisphosphate (InsP3)- and cyclic ADP-ribose (cADPR)-induced Ca2+ release. When NAADP was microinjected into intact sea urchin eggs it induced a dose-dependent increase in cytoplasmic free Ca2+ which was independent of the extracellular [Ca2+]. The Ca2+ waves elicited by microinjections of NAADP originated at the site of injection and swept across the cytosol. As previously found in sea urchin egg homogenates, NAADP-induced Ca2+ release in intact eggs was not blocked by heparin or by prior desensitization to InsP3 or cADPR. Thio-NADP, a specific inhibitor of the NAADP-induced Ca2+ release in sea urchin homogenates blocked NAADP (but not InsP3 or cADPR) injection-induced Ca2+ release in intact sea urchin eggs. Finally, fertilization of sea urchin eggs abrogated subsequent NAADP-induced Ca2+ release, suggesting that the NAADP-sensitive Ca2+ pool may participate in the fertilization response. This study demonstrates that NAADP acts as a selective Ca2+-releasing agonist in intact cells.

Original languageEnglish (US)
Pages (from-to)955-959
Number of pages5
JournalBiochemical Journal
Volume312
Issue number3
DOIs
StatePublished - 1995

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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