PKC (Protein kinase C) is a calcium-dependent and phospholipid-dependent enzyme that is activated in vivo by the lipid diacylglycerol. PKC has been shown to be involved in signal transduction and various aspects of neoplastic transformation. PKC contains an amino terminal regulatory domain and a carboxy terminal catalytic domain joined by a hinge region. Cleavage of protein kinase C in vitro results in the generation of two functional fragments corresponding to these two domains.