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 the gene coding for collagen XVII 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. Two transcript variants, one resulting from alternative splicing in the 3' UTR, have been identified for this gene.
Cell junction, hemidesmosome. Membrane; Single-pass type II membrane protein. Note=Localized along the plasma membrane of the hemidesmosome.
120 kDa linear IgA disease antigen and 97 kDa linear IgA disease antigen: Secreted, extracellular space, extracellular matrix, basement membrane.