Stratified squamous epithelial basement membrane protein that forms anchoring fibrils which may contribute to epithelial basement membrane organization and adherence by interacting with extracellular matrix (ECM) proteins such as type IV collagen. Homotrimer. Interacts with MIA3/TANGO1; facilitating its loading into transport carriers and subsequent secretion (By similarity). Transcription of COL7A1 is stimulated by TGFB1 in keratinocytes and this is possibly dependent on a putative interaction between SMADS and AP1. Prolines at the third position of the tripeptide repeating unit (G-X-Y) are hydroxylated in some or all of the chains. Mice do not express type VII collagen in their skin; they are born with extensive cutaneous blistering and die during the first two weeks of life, possibly because of complications arising from blistering; this mouse mutant resembles the autosomal recessive inherited form of the dystrophic epidermolysis bullosa (DEB) in humans. Heterozygotes by comparison display a normal phenotype.