proteoglükaan

Proteoglycans are a diverse group of heavily glycosylated proteins found in the extracellular matrix and on cell surfaces. They consist of a core protein to which one or more glycosaminoglycan (GAG) chains are covalently attached. These GAG chains are long, unbranched polysaccharides composed of repeating disaccharide units. The specific type of GAG chain, such as chondroitin sulfate, dermatan sulfate, heparan sulfate, or keratan sulfate, determines many of the proteoglycan's properties.

The structure of proteoglycans allows them to bind a large amount of water, contributing to the hydration and mechanical strength of connective tissues. They play crucial roles in a variety of biological processes, including tissue development, cell adhesion, cell signaling, and the regulation of extracellular matrix assembly. Different proteoglycans are expressed in specific tissues and at particular developmental stages, reflecting their specialized functions. For example, aggrecan is a major component of cartilage, providing its remarkable resilience. Decorin, another proteoglycan, interacts with collagen fibrils and influences their organization. Heparan sulfate proteoglycans are important for cell surface interactions and growth factor binding. Dysfunctional proteoglycans are implicated in various diseases, highlighting their importance in maintaining tissue homeostasis.