Abstract

A crucial factor in controlling protein synthesis in eukaryotic cells is the eukaryotic Initiation Factor 2, which is associated with the translational initiation phase. As ocean urchin eggs are fertilised, protein synthesis activity quickly increases, which is crucial for the formation of embryonic mobileular cycles. Here, we show that fertilisation causes eIF2 to dephosphorylate, which is accompanied by an increase in protein synthesis, and that eIF2 phosphorylation is specifically linked to an inhibition of protein synthesis and the arrest of the cell cycle. We verified that dephosphorylation of eIF2 is necessary for protein synthesis hobby and mobileular department development after fertilisation by microinjecting a phospho-mimetic protein into sea urchin eggs.