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.