Protein kinase C--an enzyme and its relatives

Abstract

Protein kinase C (PKC) is the major target for tumor-promoting phorbol esters in mammalian cells and a key mediator in signaling via phospholipid hydrolysis. The existence of at least 10 structurally related enzymes comprising the PKC family and their differential expression in mammalian tissues raises the obvious question, what functions do the members of this enzyme family fulfil in normal and malignant cell growth? Although there is a host of experimental approaches and observations relating to this question, the challenge remains to define the roles of individual PKC enzymes in various physiological responses.