Proteoglycans are basically a class of proteins that are heavily glycosylated. Here, the glycosaminoglycans are covalently attached to certain proteins called core proteins. These are the most abundant heteropolysaccharides that are present in the body. These proteins are synthesized in the rough endoplasmic reticulum, further modified in the golgi body, and are finally transported to the extracellular matrix by vesicles.
◆ They can act as endocytic receptors for the clearance of bound ligands.
◆ They cooperate with proteins such as integrins and facilitate cell migration, cell-cell interactions, and cell attachment.
◆ They bind to cations such as sodium, potassium, and calcium, as well as water, and help in regulating the movement of molecules through the matrix.
◆ Some proteoglycans either due to the core protein or the attached glycosaminoglycan chains can serve as lubricants.