Dermatan sulfate

Structure of dermatan sulfate

Dermatan sulfate is a type of glycosaminoglycan (GAG), which is a long, unbranched polysaccharide composed of repeating disaccharide units. It is a critical component of the extracellular matrix in various tissues and plays a significant role in cell signaling, tissue repair, and coagulation.

Structure

Dermatan sulfate is composed of repeating disaccharide units of iduronic acid and N-acetylgalactosamine. The iduronic acid residues can be variably sulfated, which contributes to the diversity of dermatan sulfate's biological functions. The presence of iduronic acid distinguishes dermatan sulfate from other glycosaminoglycans such as chondroitin sulfate, which contains glucuronic acid instead.

Function

Dermatan sulfate is involved in a variety of biological processes:

• Coagulation: It acts as a cofactor for heparin cofactor II, enhancing its ability to inhibit thrombin, a key enzyme in the blood coagulation cascade.
• Tissue repair: Dermatan sulfate is involved in the regulation of collagen fibrillogenesis and is important in the repair and remodeling of connective tissue.
• Cell signaling: It interacts with various growth factors and cytokines, influencing cell behavior and wound healing.

Clinical significance

Abnormalities in dermatan sulfate metabolism can lead to various mucopolysaccharidoses, a group of lysosomal storage disorders. For example, mucopolysaccharidosis type I (Hurler syndrome) and mucopolysaccharidosis type II (Hunter syndrome) are characterized by the accumulation of dermatan sulfate and other glycosaminoglycans due to enzyme deficiencies.

Biosynthesis

The biosynthesis of dermatan sulfate occurs in the Golgi apparatus of cells. It involves the polymerization of the disaccharide units followed by the epimerization of glucuronic acid to iduronic acid and subsequent sulfation. The enzymes responsible for these modifications include glycosyltransferases, epimerases, and sulfotransferases.

Degradation

Dermatan sulfate is degraded in the lysosome by a series of lysosomal enzymes. Deficiencies in these enzymes can lead to the accumulation of dermatan sulfate in tissues, contributing to the pathophysiology of mucopolysaccharidoses.

Related pages

• Glycosaminoglycan
• Extracellular matrix
• Mucopolysaccharidosis
• Heparin
• Chondroitin sulfate