Chondroitin sulfate exists mainly in the extracellular matrix or on the surface of cells as proteoglycan. Chondroitin sulfate found in cartilage is representative of its functions. Much of the chondroitin sulfate found in cartilage exists as a proteoglycan called aggrecan, forming a supramacromolecular complex with hyaluronan and link proteins. This complex forms the extracellular matrix of cartilage with type II collagen, peculiar to cartilage, which plays an important role in the cushioning mechanism of cartilage. Decorin, which exists in the skin in large quantities, adheres to collagen fibers and controls the formation of the extracellular matrix. Chondroitin sulfate found in other tissues is also involved in the formation of the extracellular matrix, as proteoglycan in many cases, exercising control of cellular characteristics, such as cell adhesion, migration, differentiation, and growth.  

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