Localization of 90-kDa heat shock protein in the kidney

Antibody against 90-kDa heat shock protein (HSP 90) was produced in rabbits. The obtained antibody was highly specific to the antigen. Using the antibody, the intrarenal distribution of HSP 90 was studied in frozen sections of normal rat kidneys by fluorescent and enzymic immunohistochemistry. HSP 90 was predominantly present in the region from the distal convoluted tubule to the medullary collecting duct at a high intensity, and in glomerular podocytes and Bowman epithelial cells at a much lower intensity. Other segments of the nephron were stained little, even at a lower dilution of the antibody. Blood vessels and interstitial tissues were not stained. HSP 90 was localized in the cytoplasm and not in the nucleus. Moreover, immunohistochemical staining of HSP 90 showed greater intensity at the luminal side of the cells. These observations suggest that HSP 90 might play important roles in the kidney.