What is Aggrecan?

Aggrecan is a key component of cartilage, primarily found in the extracellular matrix. It is classified as a large aggregating proteoglycan that plays a crucial role in maintaining the structure and resilience of cartilage tissue. The significance of aggrecan lies in its ability to bind water and other molecules, which helps cartilage withstand compressive forces. Its structure includes numerous glycosaminoglycan (GAG) chains, which contribute to its high molecular weight and the overall negative charge that attracts water molecules. In fact, aggrecan can contain over 100 GAG chains, such as chondroitin sulfate and keratan sulfate, making it vital for the hydration and functioning of cartilage. This characteristic supports its role as a primary component in articular and other types of cartilage, facilitating proper joint movement and load distribution.

The other options, while related to components of connective tissue, do not accurately reflect the defining nature of aggrecan. For example, although proteoglycans can have a high carbohydrate content, it is not specifically the case that aggrecan contains up to 95% carbohydrate by weight, making this description too broad. Additionally, while lubricants in joint fluid do play a role in making joint movement smooth, they do not