Collagen: The extracellular matrix represents a complex alloy of variable members of diverse protein families defining structural integrity and various physiological functions. The most abundant family is the collagens with more than 20 different collagen types identified thus far. Collagens are centrally involved in the formation of fibrillar and microfibrillar networks of the extracellular matrix, basement membranes as well as other structures of the extracellular matrix. Some collagens have about 15-18 vWA domains in them. The VWA domains present in these collagens mediate protein-protein interactions.
Jiyao W et al.(2023). "The conserved domain database in 2023.",