Expression of galectin-1, a new component of slit diaphragm, is altered in minimal change nephrotic syndrome.

Nephrin is an essential structural component of the glomerular slit diaphragm (SD), a highly organized intercellular junction that constitutes the ultrafiltration barrier of the kidney. Recent studies have identified two additional nephrin-interacting SD proteins (NEPH1 and NEPH2), suggesting that the zipper-like pattern of the SD is formed through complex intra- and intermolecular interactions of these proteins. However, the complexity of the SD structure suggests that additional SD components remain to be discovered.

Mammalian collagen IV.

Four decades have passed since the first discovery of collagen IV by Kefalides in 1966. Since then collagen IV has been investigated extensively by a large number of research laboratories around the world. Advances in molecular genetics have resulted in identification of six evolutionary related mammalian genes encoding six different polypeptide chains of collagen IV.

Mizoribine corrects defective nephrin biogenesis by restoring intracellular energy balance.

Proteins are modified and folded within the endoplasmic reticulum (ER). When the influx of proteins exceeds the capacity of the ER to handle the load, the ER is "stressed" and protein biogenesis is affected. We have previously shown that the induction of ER stress by ATP depletion in podocytes leads to mislocalization of nephrin and subsequent injury of podocytes.

Identification of N-linked glycosylation sites in human nephrin using mass spectrometry.

Nephrin is a type-1 transmembrane glycoprotein and the first identified principal component of the glomerular filtration barrier. Ten potential asparagine (N)-linked glycosylation sites have been predicted within the ectodomain of nephrin. However, it is not known which of these potential sites are indeed glycosylated and what type of glycans are involved.

Molecular recognition in the assembly of collagens: terminal noncollagenous domains are key recognition modules in the formation of triple helical protomers.

The alpha-chains of the collagen superfamily are encoded with information that specifies self-assembly into fibrils, microfibrils, and networks that have diverse functions in the extracellular matrix. A key self-organizing step, common to all collagen types, is trimerization that selects, binds, and registers cognate alpha-chains for assembly of triple helical protomers that subsequently oligomerize into specific suprastructures. In this article, we review recent findings on the mechanism of chain selection and infer that terminal noncollagenous domains function as recognition modules in trimerization and are therefore key determinants of specificity in the assembly of suprastructures.

Mechanism of chain selection in the assembly of collagen IV: a prominent role for the alpha2 chain.

Collagens comprise a large superfamily of extracellular matrix proteins that play diverse roles in tissue function. The mechanism by which newly synthesized collagen chains recognize each other and assemble into specific triple-helical molecules is a fundamental question that remains unanswered. Emerging evidence suggests a role for the non-collagenous domain (NC1) located at the C-terminal end of each chain.

Nephrin strands contribute to a porous slit diaphragm scaffold as revealed by electron tomography.

Nephrin is a key functional component of the slit diaphragm, the structurally unresolved molecular filter in renal glomerular capillaries. Abnormal nephrin or its absence results in severe proteinuria and loss of the slit diaphragm. The diaphragm is a thin extracellular membrane spanning the approximately 40-nm-wide filtration slit between podocyte foot processes covering the capillary surface.

Disease-causing missense mutations in NPHS2 gene alter normal nephrin trafficking to the plasma membrane.

Background: Podocin is a membrane-integrated protein that is located at the glomerular slit diaphragm and directly interacts with nephrin. The gene encoding podocin, NPHS2, is mutated in patients with autosomal-recessive steroid-resistant nephrotic syndrome (SRN). In order to study a potential pathomechanism of massive proteinuria in patients with SRN, we have investigated the trafficking and subcellular localization of five common disease-causing missense mutants of human podocin.

Monoclonal antibodies to human nephrin.

Nephrin is a 180-200-kDa transmembrane protein of the immunoglobulin superfamily. In the kidney, nephrin localizes to the slit diaphragm (SD) between interdigitating podocyte foot processes and mutations in the nephrin gene cause congenital nephrotic syndrome. In addition to this rare genetic disorder, recent reports indicate that nephrin is more generally involved in the pathogenesis of glomerular disease.

Nephrin promotes cell-cell adhesion through homophilic interactions.

Nephrin is a type-1 transmembrane protein and a key component of the podocyte slit diaphragm, the ultimate glomerular plasma filter. Genetic and acquired diseases affecting expression or function of nephrin lead to severe proteinuria and distortion or absence of the slit diaphragm. Here, we showed by using a surface plasmon resonance biosensor that soluble recombinant variants of nephrin, containing the extracellular part of the protein, interact with each other in a specific and concentration-dependent manner.

N-linked glycosylation is critical for the plasma membrane localization of nephrin.

The expression pattern, subcellular localization, and the role of glycosylation of the human nephrin was examined in transfected cells. Stable cell lines, constitutively expressing a full-length human nephrin cDNA construct, were generated from transfected immortalized mouse podocytes (IMP) and a human embryonic kidney cell line (HEK-293). Immunofluorescence confocal microscopy of transfected cells showed plasma membrane localization of the recombinant nephrin.