Calcium mobilization by dual receptors during fertilization of sea urchin eggs.
Fertilization is accompanied by a transient increase in the concentration of intracellular Ca2+, which serves as a signal for initiating development. Some of the Ca2+ appears to be released from intracellular stores by the binding of inositol trisphosphate (IP3) to its receptor. However, in sea urchin eggs, other mechanisms appear to participate. Cyclic adenosine diphosphate--ribose (cADPR), a naturally occurring metabolite of nicotinamide adenine dinucleotide, is as potent as IP3 in mobilizing Ca2+ in sea urchin eggs. Experiments with antagonists of the cADPR and IP3 receptors revealed that both Ca2+ mobilizing systems were activated during fertilization. Blockage of either of the systems alone was not sufficient to prevent the sperm-induced Ca2+ transient. This study provides direct evidence for a physiological role of cADPR in the Ca2+ signaling process.
Lee
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HC
Department of Physiology, University of Minnesota, Minneapolis 55455.
Aarhus
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R
Walseth
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TF
D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels; D036563:Cyclic ADP-Ribose / Q000031:analogs & derivatives; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D005306:Fertilization; D006493:Heparin / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors; D010063:Ovum / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000502:physiology*; D018160:Receptors, Cytoplasmic and Nuclear; D012617:Sea Urchins; D015398:Signal Transduction
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; C067025:cyclic ADP-ribose receptor; D036563:Cyclic ADP-Ribose; C082175:8-aminoadenosine cyclic 3',5'-(hydrogen phosphate) 5'-ribofuranosyl ester; D000246:Adenosine Diphosphate Ribose; D015544:Inositol 1,4,5-Trisphosphate; D006493:Heparin; D000242:Cyclic AMP; D002118:Calcium