Collagen Type VIII Alpha 2 (COL8a2)

The sequence of the alpha-1 chain is strikingly similar to that of the alpha-1 chain of type X collagen, a product of hypertrophic chondrocytes. Because of the relatively small size of the triple-helical domain, types VIII and X collagen have been called 'short chain collagens. Type VIII collagen molecules in the Descemet membrane may be heterotrimers. The 2 polypeptides are coexpressed in the Descemet membrane; the lengths of the triple-helical regions of the 2 chains are almost identical and therefore compatible with heterotrimer formation; and the proportion of alpha-1 and alpha-2 polypeptides suggests that the chain composition is two alpha-1 chains to one alpha-2 chain. COL8a2 contains a triple-helical and a carboxyl non-triple-helical domain encoded by a single, large exon, both in mice and humans.