Collagen III

Type III Collagen is a homotrimer, or a protein composed of three identical peptide chains (monomers), each called an alpha 1 chain of type III collagen. Formally, the monomers are called collagen type III, alpha-1 chain and in humans are encoded by the COL3A1 gene. Type III collagen is one of the fibrillar collagens whose proteins have a long, inflexible, triple-helical domain. In addition to being an integral structural component of many organs, type III collagen is also an important regulator of the diameter of type I and II collagen fibrils. Type III collagen is also known to facilitate platelet aggregation through its binding to platelets and therefore, play an important role in blood clotting. Type III collagen is found as a major structural component in hollow organs such as large blood vessels, uterus and bowel. It is also found in many other tissues together with type I collagen.