So we have structural proteins, we have Adhesive proteins and proteoglycans. So structural proteins are basically those proteins that give our extracellular matrix the tissue its tensile as well as compressive strength. So the most common type of structural protein in the human body is collagen. It provides the matrix with strength and it's found in connective tissue such as bone, our cartilage, blood vessels and so forth. Now, the next type of molecule that is found inside the extracellular matrix is the Adhesive protein. And we have many different types of Adhesive proteins.