Analysis of protein phosphorylation in fertilized eggs of Rana dybowskii

Abstract

The phosphorylation of 100 and 170 kDa proteins was increased in response to fertilization in eggs of Rana dybowskii. There was a transient increase of inositol 1,4,5-trisphosphate and diacylglycerol in fertilized eggs. Treatment of 0.2 mM CaCl2 in unfertilized egg homogenate also phosphorylated the 100 and 170 kDa proteins. Data suggest that the sperm signal increases IP3 content in egg cytoplasm, triggering Ca2+ release from internal storage into cell matrix to activate Ca2+-dependent protein kinases, necessary for the early embryonic development.