Calmodulin-dependent protein kinase II is activated transiently in ethanol-stimulated mouse oocytes

Abstract

The activity of calmodulin-dependent protein kinase II (CaMK(II)) was measured in mouse oocytes arrested in metaphase II and following their activation parthenogenetically. In metaphase II-arrested oocytes CaMK(II) was inactive. However, following the exposure of oocytes to ethanol, the kinase was highly active, returning to baseline activity within 15 min of their removal from ethanol. The increase in kinase activity was similar in recently ovulated and older oocytes despite an age-dependent difference in their ability to progress to interphase. Moreover, the microtubule-depolymerizing drug nocodazole, which blocks the exit from M phase in mouse oocytes, had no effect on CaMK(II) activation. These results illustrate clearly that CaMK(II) is activated in mouse oocytes in response to a rise in intracellular calcium and is acting upstream of the microtubule-dependent cyclin destruction machinery. © 1995 by Academic Press, Inc.