| Cell-cell adhesion mediated by the cadherin/catenin complexes is tight, stable and establishes or preserves tissue integrity. These adhesion molecules are essential for epithelial barriers and epithelial cell polarity. Expression of cadherins and catenins in the kidney is complex. Cadherin and catenin expression were examined by Western blot analysis, immunohistochemistry and immunofluorecence in mouse kidney. In addition, co-immunoprecipitation was used to investigate cadherin/catenin interactions. In the proximal tubule, N-cadherin/β-catenin/α-catenin and E-cadherin/β-catenin/α-catenin complexes are expressed. In contrast, two distinct E-cadherin complexes exist in the distal tubule—E-cadherin/β-catenin/α-catenin and E-cadherin/γ-catenin/α-catenin. Disruption of cadherin/catenin complexes is associated with cell injury (loss of polarity), dysfunction (altered proliferation and differentiation) and death (apoptosis and necrosis). Therefore, the expression and integrity of renal cadherin/catenin complexes were examined during acute renal failure. Selective loss of N- and Ksp-cadherin and α-catenin was observed by Western blot analysis in the late stages of mercuric chloride-induced acute renal failure, while the early stages were associated with disrupted localization and interactions of N-cadherin and α-catenin. These data are the first to describe the precise co-localization and interaction pattern of cadherins and catenins in the kidney, providing the basis for future studies on renal cadherin/catenin complexes in renal physiology and pathology. In addition, the data suggest that disruption of these complexes may be a critical component of acute renal failure. |
