Purity ≥ 85%, as determined by SDS-PAGE under reducing conditions and visualized by silver stain.Endotoxin ≤ 1EU. Nephrin is a 185kD type I transmembrane glycoprotein that belongs to the immunoglobulin superfamily (1). Mature mouse Nephrin consists of a 1042 amino acid (aa) extracellular domain (ECD) with eight Ig-like C2-set domains and one fibronectin type III domain, a 22 aa transmembrane segment, and a 156 aa cytoplasmic tail (2, 3). Within the ECD, mouse Nephrin shares 84% and 95% aa sequence identity with human and rat Nephrin, respectively. Usage of the alternate exon 1B results in a distinct N-terminal sequence that lacks a clearly defined signal peptide cleavage site (4). Nephrin is expressed primarily on podocytes in the renal glomerulus and to a lesser extent in the brain and pancreas (3, 5). The 1B isoform is not expressed in the kidney (4). Nephrin localizes to intercellular junctions between podocyte foot processes where it functions as a homophilic adhesion molecule (2,