Podocyte Shape Regulation by Semaphorin 3A and MICAL-1.

Podocytes are complex epithelial cells with foot processes that are essential for the integrity and function of the kidney glomerular filters. Podocyte foot processes linked by slit diaphragms constitute signaling platforms that tightly regulate the cell shape and the function of the filtration barrier. Semaphorin (Sema) 3A is a class 3 semaphorin secreted by podocytes that has autocrine and paracrine functions in the kidney. We have shown that Sema3A regulates podocyte shape and that excess Sema3A signaling induces glomerular disease and aggravates diabetic nephropathy. MICAL-1 is an actin-binding protein that mediates Sema3A signals in podocytes. This chapter describes the methods used to examine how Sema3A signaling regulates podocyte shape.