| Modification Notes |
Collagen Type XII is a 3,063 amino acid protein encoded by the human gene COL12A1. Collagen Type XII belongs to the fibril-associated collagens with interrupted helices (FACIT) family. Collagen Type XII is known to interact with type I collagen-containing fibrils. The COL1 domain is thought to be associated with the surface of the fibrils, while the COL2 and NC3 domains may be localized in the perifibrillar matrix. Collagen Type XII has 3 identified isoforms (named 1, 2 and 4). Isoform 1 is the long form of the protein, while 2 and 4 are missing sequences found in isoform 1. Collagen Type XII is found in Collagen Type I-containing tissues: both isoform 1 and isoform 2 appear in amnion, chorion, skeletal muscle, small intestine and cell culture of dermal fibroblasts, keratinocytes and endothelial cells. Only isoform 2 is found in lung, placenta, kidney and a squamous cell carcinoma cell line. Isoform 1 is also present in the corneal epithelial Bowman's membrane (BM) and the interfibrillar matrix of the corneal stroma, but it is not detected in the limbal BM. |