Nephrin is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

necessary for the proper functioning of the

renal In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retrop ...

filtration barrier. The renal filtration barrier consists of fenestrated endothelial cells, the glomerular basement membrane, and the

podocytes Podocytes are cells in Bowman's capsule in the kidneys that wrap around capillaries of the glomerulus. Podocytes make up the epithelial lining of Bowman's capsule, the third layer through which filtration of blood takes place. Bowman's capsule ...

of epithelial cells. Nephrin is a

transmembrane protein A transmembrane protein is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently un ...

that is a structural component of the

slit diaphragm Podocytes are cells in Bowman's capsule in the kidneys that wrap around capillaries of the glomerulus. Podocytes make up the epithelial lining of Bowman's capsule, the third layer through which filtration of blood takes place. Bowman's capsule f ...

. It is present on the tips of the podocytes as an intricate mesh connecting adjacent

foot processes Podocytes are cells in Bowman's capsule in the kidneys that wrap around capillaries of the glomerulus. Podocytes make up the epithelial lining of Bowman's capsule, the third layer through which filtration of blood takes place. Bowman's capsule ...

. Nephrin contributes to the strong size selectivity of the slit diaphragm, however, the relative contribution of the slit diaphragm to exclusion of protein by the glomerulus is debated. The extracellular interactions, both homophilic and heterophilic—between nephrin and NEPH1—are not completely understood. 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. Tyrosine phosphorylation at different sites on the intracellular tail contribute to the regulation of slit diaphragm formation during development and repair in pathology affecting podocytes.

Podocin Podocin is a protein component of the filtration slits of podocytes. Glomerulus (kidney), Glomerular capillary endothelial cells, the glomerular basement membrane and the filtration slits function as the filtration barrier of the kidney Glomerulus ...

may interact with nephrin to guide it onto

lipid raft The cell membrane, plasma membranes of cells contain combinations of glycosphingolipids, cholesterol and protein Receptor (biochemistry), receptors organized in glycolipoprotein lipid microdomains termed lipid rafts. Their existence in cellular me ...

s in podocytes, requiring the integrity of an arginine residue of nephrin at position 1160. A defect in the gene for nephrin, ''NPHS1'', is associated with

congenital nephrotic syndrome Congenital nephrotic syndrome is a rare kidney disease which manifests in infants during the first 3 months of life, and is characterized by high levels of protein in the urine (proteinuria), low levels of protein in the blood, and swelling. This ...

of the Finnish type and causes massive amounts of protein to be leaked into the urine, or

proteinuria Proteinuria is the presence of excess proteins in the urine. In healthy persons, urine contains very little protein, less than 150 mg/day; an excess is suggestive of illness. Excess protein in the urine often causes the urine to become fo ...

. Nephrin is also required for cardiovascular development.

Interactions

Nephrin has been shown to

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization advocating for the legal and human rights of children with intersex traits. The organization was founded in 2006 and fo ...

with: *

CASK A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids ...

, *

CD2AP CD2-associated protein is a protein that in humans is encoded by the ''CD2AP'' gene. Function This gene encodes a scaffolding molecule that regulates the actin cytoskeleton. The protein directly interacts with filamentous actin and a variety ...

, * CDH3 and *

CTNND1 p120 catenin, or simply p120, also called catenin delta-1, is a protein that in humans is encoded by the ''CTNND1'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a se ...

, *

FYN Proto-oncogene tyrosine-protein kinase Fyn (p59-FYN, Slk, Syn, MGC45350, Gene ID 2534) is an enzyme that in humans is encoded by the ''FYN'' gene. Fyn is a 59-kDa member of the Src family of kinases typically associated with T-cell and neurona ...

, *

KIRREL Kin of IRRE-like protein 1, also known as NEPH1, is a protein that in humans is encoded by the ''KIRREL'' gene. Function NEPH1 is a member of the NEPH protein family, which includes NEPH2 ( KIRREL3, MIMbr>607761 and NEPH3 ( KIRREL2, MIMbr>60 ...

, and *

NPHS2 Podocin is a protein that in humans is encoded by the ''NPHS2'' gene. Interactions NPHS2 has been shown to Protein-protein interaction, interact with Nephrin and CD2AP. See also * Focal segmental glomerulosclerosis References Further ...

References

External links

* {{MeshName, nephrin Proteins

Interactions

See also

References

Further reading

External links