Collagen IV (Collagen IV)
Collagen IV is found primarily in the basal lamina and comprises six a-chains, a1(IV) through a6(IV). These a-chains then form three heterotrimers: a1a1a2, a3a4a5, and a5a5a6. When the collagen IV meshwork is assembled, it provides a scaffold for the assembly of other basement membrane components through interactions with laminin, entactin/nidogen and heparan sulfate proteoglycan. Collagen IV is a substrate for growth of epithelial, endothelial, muscle and nerve cells and plays a role in the regulation of cell growth, differentiation and adhesion, and tissue formation.