Collagen Type IV (COL4A5) Native Protein

This gene encodes one of the six subunits of type IV collagen, the major structural component of basement membranes. Mutations in this gene are associated with X-linked Alport syndrome, also known as hereditary nephritis. Like the other members of the type IV collagen gene family, this gene is organized in a head-to-head conformation with another type IV collagen gene so that each gene pair shares a common promoter. Alternatively spliced transcript variants have been identified for this gene. [provided by RefSeq, Aug 2010]

COL4A5: Type IV collagen is the major structural component of glomerular basement membranes (GBM), forming a 'chicken-wire' meshwork together with laminins, proteoglycans and entactin/nidogen. Defects in COL4A5 are the cause of Alport syndrome X- linked (APSX). APSX is characterized by progressive glomerulonephritis, renal failure, sensorineural deafness, specific eye abnormalities (lenticonous and macular flecks), and glomerular basement membrane defects. The disorder shows considerable heterogeneity in that families differ in the age of end-stage renal disease and the occurrence of deafness. Deletions covering the N-terminal regions of COL4A5 and COL4A6, which are localized in a head-to-head manner, are found in the chromosome Xq22.3 centromeric deletion syndrome. This results in a phenotype with features of diffuse leiomyomatosis and Alport syndrome (DL-ATS). Belongs to the type IV collagen family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Extracellular matrix; Secreted, signal peptide; Secreted; Motility/polarity/chemotaxis

Chromosomal Location of Human Ortholog: Xq22

Cellular Component: endoplasmic reticulum lumen; collagen type IV; extracellular region; basal lamina; neuromuscular junction

Molecular Function: extracellular matrix structural constituent

Biological Process: extracellular matrix disassembly; collagen catabolic process; axon guidance; extracellular matrix organization and biogenesis; neuromuscular junction development

Disease: Alport Syndrome, X-linked