An inhibitor of p34~cdc2/cyclin B that regulates the G_2/M transition in Xenopus extracts

摘要

The activity of maturation-promoting factor (MPF), a protein kinase complex composed of p34~cdc2 and cyclin B, is undetectable during interphase but rises abruptly at the G_2/M transition to induce mitosis. After the synthesis of cyclin B, the suppression of MPF activity before mitosis has been attributed to the phosphorylation of p34~cdc2 on sites (threonine-14 and tyrosine-15) that inhibit its catalytic activity.