Collagen Type IV Alpha 3 (COL4A3) Human Recombinant Protein

Type IV collagen, the major structural component of basement membranes, is a multimeric protein composed of 3 alpha subunits. These subunits are encoded by 6 different genes, alpha 1 through alpha 6, each of which can form a triple helix structure with 2 other subunits to form type IV collagen. This gene encodes alpha 3. In the Goodpasture syndrome, autoantibodies bind to the collagen molecules in the basement membranes of alveoli and glomeruli. The epitopes that elicit these autoantibodies are localized largely to the non-collagenous C-terminal domain of the protein. A specific kinase phosphorylates amino acids in this same C-terminal region and the expression of this kinase is upregulated during pathogenesis. This gene is also linked to an autosomal recessive form of Alport syndrome. The mutations contributing to this syndrome are also located within the exons that encode this C-terminal region. 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. [provided by RefSeq, Jun 2010]

COL4A3: 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. Autoantibodies against the NC1 domain of alpha 3(IV) are found in Goodpasture syndrome, an autoimmune disease of lung and kidney. Defects in COL4A3 are a cause of Alport syndrome autosomal recessive (APSAR). APSAR is characterized by progressive glomerulonephritis, glomerular basement membrane defects, renal failure, sensorineural deafness and specific eye abnormalities (lenticonous and macular flecks). The disorder shows considerable heterogeneity in that families differ in the age of end-stage renal disease and the occurrence of deafness. Defects in COL4A3 are a cause of benign familial hematuria (BFH); also known as thin basement membrane nephropathy. BFH is characterized by persistent hematuria, an electron microscopically detectable thin glomerular basement membrane (GBM) and an autosomal dominant mode of inheritance. Renal function remains normal. In children, differentiation between BFH and AS can be difficult, because both disorders are manifested by persistent hematuria and thin GBM at that age. Defects in COL4A3 are a cause of Alport syndrome autosomal dominant (APSAD). Alport syndrome is characterized by progressive glomerulonephritis, glomerular basement membrane defects, renal failure, sensorineural deafness and specific eye abnormalities (lenticonous and macular flecks). The disorder shows considerable heterogeneity in that families differ in the age of end-stage renal disease and the occurrence of deafness. Belongs to the type IV collagen family. 5 isoforms of the human protein are produced by alternative splicing.

Protein type: Secreted, signal peptide; Secreted

Chromosomal Location of Human Ortholog: 2q36-q37

Cellular Component: endoplasmic reticulum lumen; collagen type IV; extracellular region; basement membrane

Molecular Function: metalloendopeptidase inhibitor activity; integrin binding; protein binding; extracellular matrix structural constituent; structural molecule activity

Biological Process: caspase activation; axon guidance; extracellular matrix organization and biogenesis; blood circulation; glomerular basement membrane development; cell proliferation; extracellular matrix disassembly; collagen catabolic process; negative regulation of cell proliferation; negative regulation of angiogenesis; sensory perception of sound; cell surface receptor linked signal transduction; cell adhesion

Disease: Hematuria, Benign Familial; Alport Syndrome, Autosomal Dominant; Alport Syndrome, Autosomal Recessive