Abstract
The podocyte possesses a unique morphology characterized by a large cell body and numerous foot processes, which enwrap the glomerular capillary. The intercellular space between foot processes is kept wide open to pass through the glomerular filtrate and connected with the slit diaphragms. It has been believed that the slit diaphragm plays an important role in permeability barrier function, because the lack of the components of slit diaphragm causes massive proteinuria. The podocyte is derived from the polarized epithelial cell mass converted from the undifferentiated metanephric mesenchyme at the first stage of glomerular development. The dramatic structural and functional transformation of the podocyte is occurred during differentiation of the kidney. The morphological changes of podocytes seen under the pathological condition are tightly associated with the pathogenesis of proteinuria. The organization and maintenance of the unique cell shape is achieved by the novel cytoskeletal elements. Especially, regulation of actin filaments in foot processes is important for maintaining integrity of the cytoskeleton and organization of the slit diaphragm. Recently, we have focused on two myosins which are actin-binding motor proteins and expressed in podocyte. In addition, we have investigated a new cell signaling system at the slit diaphragm. In this lecture, I review our recent progress in the function of those molecules in health and disease.
