Immunolocalization of Ksp-cadherin in the adult and developing rabbit kidney

The potential for Ksp-cadherin involvement in either the development or mai ntenance of the metanephric kidney was assessed by immunocytochemical local ization of a monoclonal antibody directed against the rabbit isoform of Ksp -cadherin in both neonatal and adult, rabbit kidneys. In the adult kidney K sp-caaherin expression was detected on the basolateral membrane of all cell , types in both the tubular nephron and the collecting system. Immunoelectr on microscopy indicated that Ksp-cadherin was expressed at uniform levels a long the entire length of both the lateral membranes and the basal infoldin gs of all tubular epithelial cell types. In the nephrogenic zone of the neo natal rabbit kidney Ksp-cadherin expression was detected exclusively on the basolateral membranes of epithelial cells in the more highly differentiate d regions of the expanding ureteric duct. In the highly differentiated cort icomedullary and medullary regions of the neonatal kidney, distinct basolat eral staining was observed in all segments of the tubular nephron and the c ollecting system. The relatively late appearance of Ksp-cadherin expression in the developing metanephros indicates that Ksp-cadherin probably does no t participate in the direction of renal morphogenesis. However, the high le vels of Ksp-cadherin expression observed in all segments of the tubular nep hron and the collecting system in the adult kidney suggests that it may pla y a role in the maintenance of the terminally differentiated tubular epithe lial phenotype.