Protein kinase C isozymes and substrates.

As most cells express more than one type of protein kinase C (PKC), it has been difficult to establish the role of individual PKCs in cellular functions. Isozyme differences in cofactor requirements and subcellular location, in addition to variability in expression of PKCs and substrates among various cell types, are all involved in determining the effects of PKC activation. Recent identification of cellular PKC-targeting proteins and of isozyme-selective functions has provided new insight into the roles of individual PKCs in cellular processes.