Dynamic (re)organization of the podocyte actin cytoskeleton in the nephrotic syndrome

The visceral glomerular epithelial cell, also known as the podocyte, plays an important role in the maintenance of renal glomerular function. This cell type is highly specialized and its foot processes together with the interposed slit diaphragm (SD) form the final barrier to urinary protein loss. Effacement of foot processes is associated with the development of proteinuria and—if not reversed in a certain time—with permanent deterioration of the glomerular filter. To maintain an intact glomerular filter barrier, podocyte-podocyte interactions and podocyte interactions with the glomerular basement membrane (GBM) are essential. Recent years have highlighted podocyte functions by unraveling the molecular composition of the SD, but have also clarified the important role of the podocyte actin cytoskeleton, and the podocyte-GBM interaction in the development of foot process (FP) effacement. This review provides an update of podocyte functions with respect to novel podocyte-specific proteins and also focuses on the dynamic interaction between the actin cytoskeleton of podocytes, their cell surface receptors and the GBM.