Characterization of protein kinase C expression in human kidney.

Protein kinase C (PKC), the calcium and phospholipid-dependent kinase, is a key enzyme for regulation of growth and differentiation of various cells and tissues. Abnormalities of PKC modulation may cause diseases such as neoplasia. The present study was designed to demonstrate localization of PKC in normal human nephron segments. Surgically extirpated specimens for renal tumor were used. PKC was determined by immunoblotting and immunohistochemical methods using specific antibody against PKC that recognizes alpha and beta subtypes of this enzyme. Immunoblotting study demonstrated PKC in the cytosolic fractions of homogenized cortical tubules and medullary tubules prepared from morphologically normal part of the kidney. PKC was faintly detected in glomerular supernatants. Immunohistochemical study revealed that PKC was present throughout the nephron and especially concentrated in the cytoplasm of the proximal tubules and the medullary collecting ducts. The results indicate that PKC appears to play a role in regulation of normal nephron function in human kidney.