What are the types of structural proteins in the extracellular matrix and their functions?

The types of structural protein in the ECM include collagens, elastins, laminins, tenascins, and fibronectins. Collagens are the primary form of structural proteins found in the ECM, as they provide durability and also play a role in migration and adhesion. They are also the most abundant protein in the body. More specifically, collagen types I, II, III, V, and XI are found in the ECM. Elastin is closely linked with collagen, and provides the ability for the skin to recover from stretching in soft tissue. Fibronectin has a key role in cell adhesion, wound healing, and embryonic development. Laminins are also located in the basement membrane and play key roles in differentiation and migration. In embryos, laminins are among the first proteins of the ECM to appear. Tenascins are a group of proteins that occurs in five different forms, TN-C, TN-R, TN-W, TN-X, and TN-Y. They are typically found in the connective tissue, and also in the brain. Tenascin also plays a role in mechanical activity.