Regulation of recombinant PKC alpha activity by protein phosphatase 1 and protein phosphatase 2A.

The sensitivity of PKC alpha to two protein phosphatases (PP1 and PP2A) has been studied. The results show that both phosphatases reversibly inhibit PKC alpha activity suggesting an effect at PKC autophosphorylation sites and not at transphosphorylation sites. Moreover, PP1 has been found at low concentration to activate PKC alpha implying the existence of an inhibitory phosphorylation site. Further, PKC alpha has been shown to phosphorylate PP2A at its regulatory subunit B. Copyright 1998 Academic Press.