The heterogeneity of protein kinase C in various rat tissues.

Expression of multiple subspecies of protein kinase C (PKC) was studied in various rat tissues. Three types of the enzyme designated type I, II, and III were analyzed, which have the structures of gamma-, beta- (beta I- and beta II-), and alpha-sequence, respectively. Type I enzyme was found only in the central nervous tissue, whereas type III enzyme appeared to be commonly present in various tissues such as liver, spleen, lung, testis, heart, and kidney. Type II enzyme was also found in these tissues. However, immunoblot and biochemical analysis indicated that type II enzyme of lung and heart was distinct from that of other tissues. The tissue-specific expression of PKC suggests that each subspecies of this enzyme has a defined function in processing and modulating tissue responses to external stimuli.