Anti-Nephrin Antibody, clone 3B6.1 clone 3B6.1, from mouse

Nephrin (UniProt O60500; also known as Renal glomerulus-specific cell adhesion receptor) is encoded by the NPHS1 (also known as NPHN) gene (Gene ID 4868) in human. The transmembrane protein nephrin is an essential component of the podocyte slit diaphragm, the main functional unit of the glomerulus. The renal filtration barrier consists of fenestrated endothelial cells, the glomerular basement membrane (GBM), and the podocytes of epithelial cells. The interdigitating podocyte foot processes are bridged by a 40 nm wide extracellular structure known as the slit diaphragm. Together with the capillary endothelium and GBM, podocytes comprise the glomerular filtration barrier. The GBM functions as a coarse prefilter for large plasma proteins, whereas the slit diaphragm serves as an isoporous ultrafilter with pores smaller than albumin. Nephrin gene mutations are linked to the autosomal recessive disorder congenital nephrotic syndrome of the Finnish type (NPHS1) characterized by massive proteinuria already in utero and nephrosis soon after birth. Both nephrin and the slit diaphragm are reported to be absent in NPHS1 cases. Nephrin is produced with a signal peptide (a.a. 1-22), the removal of which yields the mature protein with a large extracellular region (a.a. 23-1055), followed by a transmembrane segment (a.a. 1056-1076) and a cytoplasmic tail (a.a. 1077-1241). The extracellular region contains eight C-type Ig-like domains (a.a. 27-939), and a Fibronectin type III domain (a.a. 943-1038), while the cytoplasmic tail contains the NPHS2-binding region (a.a. 1160-1241).