Distinct mechanisms of regulation of protein kinase C epsilon by hormones and phorbol diesters.

In this study, we examined the effects of T cell activators on the regulation of protein kinase C (PKC) isozymes present in thymocytes.Using affinity-purified anti-PKC antisera, we determined that the major PKC isoforms in murine thymocytes are PKCB and PKCe.The CD4+/CD8+ thymocyte subset expressed high levels of both PKCj3 and PKCc, whereas the CD4-/ CD8-subset expressed much less of both.PKCB was down-regulated following treatment of thymocytes with phorbol 12-myristate acetate (PMA) (2 X M)