The heterogeneity and differential expression of multiple species of the protein kinase C family

Although once considered as a single entity, enzymological and molecular cloning analysis has revealed that protein kinase C exists as a family of multiple subspecies with subtle individual characteristics. The members of this family have closely related structures, but their mode of activation, and kinetic and catalytic properties appear to differ slightly from one another. Biochemical and immunocytochemical studies indicate their differential regional expression and distinct cellular localization. It is attractive to surmise that each member of this family has a defined function in processing and modulating the physiological and pathological response of different cell types to a variety of external stimuli.