Expression of protein kinase C isoforms in renal tissue

Expression of protein kinease C isoforms in renal tissue. PKC plays a central role for the regulation of renal function. PKC consists of a family of isoenzymes. By employing Northern blot techniques we have demonstrated that mRNA transcripts for the classical Ca 2+ -dependent, diacylglycerol-activated isoform α, the novel, Ca 2+ -independent isoform δ and the atypical isoform ζ are abundantly expressed in the rat kidney. The novel PKC-e was weakly expressed. The classical PKCs βI, βII and γ could not be detected. The mRNA expression of PKC-δ and -ζ increased with age. The intrarenal localization of PKC-α, -δ and -ζ isoforms were studied in the adult kidney using in situ hybridization. In the cortex, the PKC-α isofom showed the strongest hybridization signal. PKC α, δ and ζ were all distributed in the outer medulla. The PKC-α probe detected particularly strong signal in the outer stripe of the outer medulla. Western blot confirmed the presence of the PKC-α, -δ and -ζ enzymes in renal tissue. The results show cell-specific and developmentally-dependent expression of three types of PKC isoforms with different responses to diacylglycerol and calcium. The developmental increase of both PKC-δ and PKC-ζ suggests a specific role for these isoforms for the functional regulation of the mature kidney.