REGULATION OF PROTEIN-KINASE-C - A TALE OF LIPIDS AND PROTEINS

Protein kinase C (PKC) is a family of serine/threonine kinases implica ted in intracellular signalling events triggered in response to a larg e variety of agonists. Currently, 11 mammalian PKC isoforms have been identified which are divided into three groups, the calcium-dependent, the non-calcium-dependent and the atypical isoforms. Common to all me mbers is the presence of an aminoterminal regulatory domain, which ren ders the kinase inactive by interacting with the carboxyterminal catal ytic domain. Thus, intracellular PKC activation requires the release o f this autoinhibitory restraint, which, as this review summarizes, may involve both interactions with lipids and proteins. Furthermore, post -translational PKC phosphorylation events, required to convert PKC to an activation competent state, are discussed.