Heparan sulfates (HS) are linear polysaccharides belonging to the glycosaminoglycan (GAG) family.
They are composed of repeating disaccharide units, consisting of glucuronic acid and N-acetylglucosamine, with various sulfation patterns.
Structure:

The structure of heparan sulfates can vary in terms of sulfation patterns and sequence, resulting in considerable heterogeneity.
Sulfation can occur at different positions, including the 2-O, 6-O, and N-sulfation of glucosamine residues.
Biological Functions:

Cell Surface Proteoglycans: Heparan sulfates are often found as side chains of proteoglycans on cell surfaces.
Cellular Signaling: They play crucial roles in various biological processes, including cell signaling, adhesion, and the regulation of growth factors.
Interaction with Proteins:

Heparan sulfates interact with a wide range of proteins, including growth factors, cytokines, and enzymes.
These interactions are essential for the modulation of signaling pathways and cellular behaviors.
Extracellular Matrix (ECM):

Heparan sulfates contribute to the structure and function of the extracellular matrix (ECM), influencing tissue organization and cell behavior.
Anticoagulant Properties:

Due to their negative charge, heparan sulfates possess anticoagulant properties by interacting with antithrombin III and inhibiting blood clotting.
Pathological Implications:

Alterations in heparan sulfate structure or expression are associated with various diseases, including cancer, neurodegenerative disorders, and certain genetic disorders.
Therapeutic Applications:

Modified heparan sulfates or synthetic mimetics are explored for therapeutic applications, including anticoagulant drugs and agents targeting specific signaling pathways.
Understanding the diverse functions of heparan sulfates is crucial for unraveling their contributions to both normal physiological processes and pathological conditions. The unique structure and interactions of heparan sulfates make them key players in cellular and molecular biology