AFLUID July 46/1

Thomson, R. Brent, and Peter S. Aronson. Immunolocalization of Ksp-cadherin in the adult and developing rabbit kidney. Am. J. Physiol. 277 (Renal Physiol. 46): F146–F156, 1999.—The potential for Ksp-cadherin involvement in either the development or maintenance of the metanephric kidney was assessed by immunocytochemical localization of a monoclonal antibody directed against the rabbit isoform of Kspcadherin in both neonatal and adult rabbit kidneys. In the adult kidney Ksp-cadherin expression was detected on the basolateral membrane of all cell types in both the tubular nephron and the collecting system. Immunoelectron microscopy indicated that Ksp-cadherin was expressed at uniform levels along the entire length of both the lateral membranes and the basal infoldings of all tubular epithelial cell types. In the nephrogenic zone of the neonatal rabbit kidney Kspcadherin expression was detected exclusively on the basolateral membranes of epithelial cells in the more highly differentiated regions of the expanding ureteric duct. In the highly differentiated corticomedullary and medullary regions of the neonatal kidney, distinct basolateral staining was observed in all segments of the tubular nephron and the collecting system. The relatively late appearance of Ksp-cadherin expression in the developing metanephros indicates that Kspcadherin probably does not participate in the direction of renal morphogenesis. However, the high levels of Kspcadherin expression observed in all segments of the tubular nephron and the collecting system in the adult kidney suggests that it may play a role in the maintenance of the terminally differentiated tubular epithelial phenotype.