Filtration slits

Foot processes of podocytes interdigitate with one another forming filtration slits (or slit pores) that, in contrast to those in the glomerular endothelium, are spanned by slit diaphragms.

Structure
Some studies suggest that the size of the filtration slits restricts the passage of large molecules (eg, serum albumin) and cells (eg, red blood cells and platelets). Proteins that are required for the correct function of the slit diaphragm include nephrin, NEPH1, NEPH2, podocin, and CD2AP.