The podocyte foot process network is required for glomerular maturation. (A) Under physiologic conditions, podocytes establish a foot process network during glomerular development and maturation. Surface infolding is formed by podocyte foot processes, glomerular basement membrane, and mesangial cells, separating the capillaries from each other. (B) In aPKC double mutant mice, failure to establish a process network results in an arrest of glomerular maturation.