Kin of irregular chiasm-like protein 1(Kirrel1), also known as Nephrin-like protein 1(Neph1), belongs to the immunoglobulin superfamily. Kirrel1 plays a significant role in the normal development and function of the glomerular permeability. It is a signaling protein that needs the presence of TEC kinases to fully trans-activate the transcription factor AP-1. The knockout of this gene could result in perinatal lethality accompanied by proteinuria, and effacement of glomerular podocytes. Kirrel1 is abundantly expressed in kidney and specifically expressed in podocytes of kidney glomeruli. Its’ subunit interacts with TJP1/ZO-1 and with NPHS2/podocin (via the C-terminus) and interacts with NPHS1/nephrin (via the Ig-like domains). This interaction is dependent on KIRREL glycosylation. Kirrel1 also interacts when tyrosine-phosphorylated with GRB2.