Nephrin is a transmembrane protein that is a structural component of the slit diaphragm.

[5] It is present on the tips of the podocytes as an intricate mesh connecting adjacent foot processes.

[6] In addition to eight immunoglobulin G–like motifs and a fibronectin type 3 repeat, nephrin has a single transmembrane domain and a short intracellular tail.

[6][7] Tyrosine phosphorylation at different sites on the intracellular tail contribute to the regulation of slit diaphragm formation during development[7] and repair in pathology affecting podocytes.

[7] A defect in the gene for nephrin, NPHS1, is associated with congenital nephrotic syndrome of the Finnish type and causes massive amounts of protein to be leaked into the urine, or proteinuria.