Collagen VI acts as a cell-binding protein. Trimers composed of three different chains: alpha-1(VI), alpha-2(VI), and alpha-3(VI) or alpha-4(VI) or alpha-5(VI) or alpha-6(VI). Prolines at the third position of the tripeptide repeating unit (G-X-Y) are hydroxylated in some or all of the chains. Belongs to the type VI collagen family.