Target Background
This gene encodes the alpha chain of type XVII collagen. Unlike most collagens, collagen XVII is a transmembrane protein. Collagen XVII is a structural component of hemidesmosomes, multiprotein complexes at the dermal-epidermal basement membrane zone that mediate adhesion of keratinocytes to the underlying membrane. Mutations in this gene are associated with both generalized atrophic benign and junctional epidermolysis bullosa. Two homotrimeric forms of type XVII collagen exist. The full length form is the transmembrane protein. A soluble form, referred to as either ectodomain or LAD-1, is generated by proteolytic processing of the full length form. [provided by RefSeq, Jul 2008],disease:Defects in COL17A1 are a cause of generalized atrophic benign epidermolysis bullosa (GABEB) [MIM:226650]. GABEB is a non-lethal, adult form of junctional epidermolysis bullosa characterized by life-long blistering of the skin, associated with hair and tooth abnormalities.,function:May play a role in the integrity of hemidesmosome and the attachment of basal keratinocytes to the underlying basement membrane.,function:The 120 kDa linear IgA disease antigen is an anchoring filament component involved in dermal-epidermal cohesion. Is the target of linear IgA bullous dermatosis autoantibodies.,miscellaneous:Both the 120 kDa linear IgA disease antigen and the 97 kDa linear IgA disease antigen of COL17A1, represent major antigenic targets of autoantibodies in patients with linear IgA disease (LAD). LAD is a subepidermal blistering disorder characterized by tissue-bound and circulating IgA autoantibodies to the dermal-epidermal junction. These IgA autoantibodies preferentially react with 97 and the 120 kDa forms, but not with the full-length COL17A1, suggesting that the cleavage of the ectodomain generates novel autoantigenic epitopes.,PTM:Prolines at the third position of the tripeptide repeating unit (G-X-Y) are hydroxylated in some or all of the chains.,PTM:The ectodomain is shedded from the surface of keratinocytes resulting in a 120-kDa soluble form, also named as 120 kDa linear IgA disease antigen. The shedding is mediated by membrane-bound metalloproteases. This cleavage is inhibited by phosophorylation at Ser-544.,PTM:The intracellular/endo domain is disulfide-linked.,sequence caution:Contaminating sequence. Potential poly-A sequence.,subcellular location:Exclusively localized to anchoring filaments. Localized to the epidermal side of split skin.,subcellular location:Localized along the plasma membrane of the hemidesmosome.,subcellular location:Localized in the lamina lucida beneath the hemidesmosomes.,subunit:Homotrimers of alpha 1(XVII)chains.,tissue specificity:Stratified squamous epithelia. Found in hemidesmosomes. Expressed in cornea, oral mucosa, esophagus, intestine, kidney collecting ducts, ureter, bladder, urethra and thymus but is absent in lung, blood vessels, skeletal muscle and nerves.,
