Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033687 (proteinuria)
 24,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A properly established and maintained podocyte intercellular junction, or slit diaphragm, is a necessary component of the selective permeability barrier of the kidney glomerulus. The observation that mutation or deletion of the slit diaphragm transmembrane protein nephrin results in failure of podocyte foot process morphogenesis and concomitant proteinuria first suggested the hypothesis that nephrin serves as a component of a signaling complex that directly integrates podocyte junctional integrity with cytoskeletal dynamics. The observations made herein provide the first direct evidence to our knowledge for a phosphorylation-mediated signaling mechanism by which this integrative function is derived. Our data support the model that during podocyte intercellular junction formation, engagement of the nephrin ectodomain induces transient Fyn catalytic activity that results in nephrin phosphorylation on specific nephrin cytoplasmic domain tyrosine residues. We found that this nephrin phosphorylation event resulted in recruitment of the SH2-SH3 domain-containing adapter protein Nck and assembly of actin filaments in an Nck-dependent fashion. Considered in the context of the role of nephrin family proteins in other organisms and the integral relationship of actin dynamics and junction formation, these observations establish a function for nephrin in regulating actin cytoskeletal dynamics.
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PMID:Nephrin ectodomain engagement results in Src kinase activation, nephrin phosphorylation, Nck recruitment, and actin polymerization. 1695 21

Nephrotic syndrome (NS) is one of the most frequent syndromes characterized namely by heavy proteinuria. Majority of NS occurs as a sporadic form, the incidence of familial cases is from 3 to 5%. Seven genes have been recognized till present, which mutations are responsible for severe forms of NS: NPHS1, NPHS2, ACTN4, CD2AP and WT1, TRPC6, LAMB2. Proteins encoded by these genes (nephrin, podocin, alpha-actinin-4, an adapter protein anchoring CD2 and others) influence the function of the podocytes. In cases of mutation in NPHS1 gene, causing congenital nephrotic syndrome of the Finnish type (CNF), resistance to steroid therapy occurs regularly and recurrence of proteinuria after renal transplantation is about 20-25%. Mutations in NPHS2 gene lead to autosomal recessive steroid resistant nephrotic syndrome (histologically focal segmental glomerulosclerosis). It was concluded that patients with steroid resistant nephrotic syndrome (SRNS) with homozygous or compound heterozygous mutations in NPHS2 have reduced risk for recurrence of focal segmental glomerulosclerosis (FSGS) in renal transplant (only 8% in comparison with 35% in patients without mutation in NPHS2). A functional polymorphism of NPHS2 gene--R229Q was associated with a late-onset nephrotic syndrome and also with an increased risk of microalbuminuria in the general population. The R229Q variant encodes a protein with lower affinity for binding nephrin. This polymorphism appears to enhance susceptibility to FSGS in association with a second mutant NPHS2 allele. There are also 3 genetic loci connected with autosomal dominant forms of FSGS: ACTN4, TRPC6 and CD2AP (found only in the mice models). These forms of FSGS differ from the recessive form by later-onset and more slowly progressive course of the disease; these mutations seem to be responsible for only a fraction of the autosomal dominant pattern of FSGS.
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PMID:Genetic basis of nephrotic syndrome--review. 1675 99

Podocyte loss is central to the progression of proteinuric kidney diseases leading to end-stage kidney disease (ESKD), requiring renal replacement therapy, such as dialysis. Despite modern tools and techniques, the 5-year mortality of some patients requiring dialysis remains at about 70% to 80%. Thus, there is a great unmet need for podocyte-specific treatments aimed at preventing podocyte loss and the ensuing development of ESKD. Here, we show that ablation of the podocyte death-promoting protein dendrin delays the onset of ESKD, thereby expanding the life span of mice lacking the adapter protein CD2AP. Ablation of dendrin delays onset and severity of proteinuria and podocyte loss. In addition, dendrin ablation ameliorates mesangial volume expansion and up-regulation of mesangial fibronectin expression, which is mediated by a podocyte-secreted factor. In conclusion, onset of ESKD and death can be markedly delayed by blocking the function of dendrin.
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PMID:Dendrin ablation prolongs life span by delaying kidney failure. 2650 76