Intrarenal distribution of rabbit PKC zeta

Abstract

To elucidate roles of protein kinase C (PKC) ζ in rabbit kidney, PKC ζ was cloned from a rabbit kidney cortex cDNA library. Sequencing revealed a 2113 nt insert with an open reading frame encoding a protein of 591 amino acids. The predicted amino acid sequence is 93.7% identical with rat PKC ζ. In situ hybridization in rabbit kidney with a riboprobe generated from the cloned cDNA, showed PKC ζ mRNA is highly expressed in proximal tubule, thick limb, and collecting duct. No message was detected over glomerular cells. Immunohistochemical studies using a monoclonal antibody against PKC ζ confirmed this distribution with low expression in vascular elements and high expression in tubule epithelium. Confocal microscopy showed diffuse cytosolic immunoreactivity in confluent cultured cortical collecting ducts (CCDs). However, in subconfluent cells, immunoreactivity was restricted to the peri-nuclear area. This differential distribution of PKC ζ in the CCD suggests that PKC ζ action be involved in growth and differentiation of the collecting duct. In conclusion, PKC ζ is differentially expressed in the rabbit kidney with high expression in the tubule epithelium and little expression in vascular elements. These studies suggest an important role for PKC ζ along the nephron.