Ca(2+)-induced Ca2+ release in sea urchin egg homogenates: modulation by cyclic ADP-ribose.
Calcium-induced calcium release (CICR) may function widely in calcium-mediated cell signaling, but has been most thoroughly characterized in muscle cells. In a homogenate of sea urchin eggs, which display transients in the intracellular free calcium concentration ([Ca2+]i) during fertilization and anaphase, addition of Ca2+ triggered CICR. Ca2+ release was also induced by the CICR modulators ryanodine and caffeine. Responses to both Ca2+ and CICR modulators (but not Ca2+ release mediated by inositol 1,4,5-trisphosphate) were inhibited by procaine and ruthenium red, inhibitors of CICR. Intact eggs also displayed transients of [Ca2+]i when microinjected with ryanodine. Cyclic ADP-ribose, a metabolite with potent Ca(2+)-releasing properties, appears to act by way of the CICR mechanism and may thus be an endogenous modulator of CICR. A CICR mechanism is present in these nonmuscle cells as is assumed in various models of intracellular Ca2+ wave propagation.
Galione
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A
Department of Biology, Johns Hopkins University, Baltimore, MD 21218.
Lee
H C
HC
Busa
W B
WB
D000246:Adenosine Diphosphate Ribose / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D036563:Cyclic ADP-Ribose; D004533:Egtazic Acid / Q000494:pharmacology; D007700:Kinetics; D010063:Ovum / Q000187:drug effects / Q000502:physiology*; D012617:Sea Urchins; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D036563:Cyclic ADP-Ribose; D000246:Adenosine Diphosphate Ribose; D004533:Egtazic Acid; D000255:Adenosine Triphosphate; D002118:Calcium