Localization of protein kinase C in human skeletal muscle

The immunolocalization of protein kinase C (PKC) isozymes alpha, beta I and beta II, was investigated in human skeletal muscle. All three isozymes were present on the muscle fiber surface membrane and within the muscle fibers. The alpha-isozyme was most clearly delineated on the surface membrane of the muscle fiber and on small blood vessels in the connective tissue. The axons of myelinated intramuscular nerves stained intensely for the beta I isozyme, whereas the endoneurial connective tissue reacted more strongly for the alpha- and beta II-isozymes. PKC isozymes may regulate intracellular signal transduction in human skeletal muscle, as in the other tissues, but their exact role in muscle remains unknown.