Cell-surface N-linked glycans with terminal galactose

Cell-surface N-linked glycans with terminal galactose are complex carbohydrate structures covalently attached to the asparagine residues of membrane-bound proteins [Varki et al., 2015]. These glycans serve as critical recognition motifs in the "glyco-code," mediating interactions between cells and their environment through binding with endogenous lectins like galectins and the asialoglycoprotein receptor (ASGPR) [Varki et al., 2015; Stockert, 1995]. Under normal physiological conditions, terminal galactose residues are typically "capped" by sialic acid; however, their exposure—often termed desialylation—acts as a molecular signal for the clearance of glycoproteins by the liver [Stockert, 1995]. In pathological states, particularly cancer and fibrosis, aberrant glycosylation leads to the overexposure of these terminal galactose residues [Pinho & Reis, 2015]. This exposure facilitates tumor cell adhesion, metastasis, and immune evasion by interacting with Galectin-3, a pro-inflammatory and pro-fibrotic lectin [Pinho & Reis, 2015]. Therapeutic strategies involving these glycans primarily focus on the use of galectin inhibitors, such as Belapectin (GR-MD-02) and GB1211, which block the interaction between the protein and the galactosylated glycan [Harrison et al., 2021]. Additionally, the high affinity of hepatic ASGPR for terminal galactose is exploited in drug delivery systems to target therapeutics specifically to the liver [Stockert, 1995]. Understanding the spatial and structural distribution of these glycans is essential for developing precise glycan-targeted therapies and diagnostic tools for chronic liver diseases and various malignancies.

Other names

AsialoglycansTerminal galactose-containing N-glycansGalactosylated N-glycansGal-terminated N-linked oligosaccharidesAsialo-N-glycans

Competitive inhibition of lectin-glycan interactions, specifically blocking the binding of galectins to terminal galactose residues to prevent pro-tumorigenic and pro-fibrotic signaling.