Transmembrane Glycoprotein (跨膜糖蛋白)

Transmembrane glycoproteins are important components of cell membranes and are characterized by oligosaccharide chains covalently linked to polypeptide chains. Glycosylation sites are mainly located in their extracellular regions, achieved by N-linked glycosylation (linked to asparagine residues) or O-linked glycosylation (linked to serine or threonine residues). Sugar chains not only provide structural stability to proteins but also confer functional specificity. Many transmembrane glycoproteins are receptors, such as G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs). Most （clusters of differentiation）CD molecules are also transmembrane glycoproteins expressed on the surface of antigen-presenting cells^[1][2].