A synthetic peptide of the pseudosubstrate domain of protein kinase C blocks cytoplasmic alkalinization during activation of the sea urchin egg.
Multiple second messenger pathways have been proposed for transduction of the sperm-egg fusion event during fertilization of sea urchin eggs. Cytoplasmic alkalinization due to increased Na(+)-H+ antiport has been causally linked to many of the metabolic events during fertilization. Two possible second messenger pathways coupling sperm-egg fusion and antiporter activity are activation of protein kinase C (PKC) and Ca2(+)-calmodulin kinase. A selective inhibitor of PKC is PKC(19-36), a synthetic peptide of the pseudosubstrate domain of the kinase. Injection of PKC(19-36) into unfertilized sea urchin eggs blocked cytoplasmic alkalinization during activation by phorbol 12-myristate 13-acetate, a PKC agonist. The rise in pH during fertilization was partially blocked by PKC(19-36), which suggested that multiple pathways regulate the antiporter during fertilization. The use of fluorescein chromophores to measure intracellular pH in sea urchin eggs is also discussed.
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Department of Zoology, Iowa State University, Ames 50011.
Buck
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D000818:Animals; D005260:Female; D005306:Fertilization / Q000187:drug effects; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D008297:Male; D010063:Ovum / Q000187:drug effects / Q000502:physiology*; D010455:Peptides / Q000494:pharmacology*; D011480:Protease Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D012617:Sea Urchins; D013050:Spectrometry, Fluorescence; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D005452:Fluoresceins; D005456:Fluorescent Dyes; D010455:Peptides; D011480:Protease Inhibitors; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate