Structure and function of tight junctions involved in slit diaphragms

点击翻译按钮获取中文摘要

Tight junctions are the main intercellular junctions of podocytes of the renal glomerulus under nephrotic conditions. Their requisite components, claudins, still remain to be identified. Absolute quantitative real-time PCR using cDNA of isolated rat glomeruli showed that claudin-5 was the most abundantl claudin expressed in glomeruli. In situ hybridization and immunolocalization studies revealed that claudin-5 was localized mainly in podocytes. Claudin-5 protein was observed on the entire surface of podocytes including slit diaphragms, and was inclined to be concentrated on tight junctions in puromycin aminonucleoside nephrosis. Immunoprecipitation studies using anti-claudin-5 and glomerular lysates revealed the association of claudin-5 and nephrin. It is concluded that claudin-5 is a main claudin expressed in podocytes and that the formation of tight junctions in the nephrosis may be due to local recruitment of claudin-5 rather than due to total upregulation of the claudin protein levels.