ST6GAL1

ST6-beta-galactoside alpha-2,6-sialyltransferase 1, commonly abbreviated ST6GAL1, is a human glycosyltransferase encoded by the ST6GAL1 gene. The enzyme catalyzes the transfer of sialic acid from the donor substrate CMP-N-acetylneuraminic acid to the terminal galactose of N- and O-linked glycans, forming alpha-2,6-linked sialylated structures such as Neu5Acα2-6Galβ1-4GlcNAc. It can also act on certain glycosphingolipids. This activity contributes to the generation of diverse glycan epitopes that influence cell recognition and signaling.

ST6GAL1 is a Golgi-resident enzyme. It is a type II transmembrane protein with a short cytoplasmic tail, a single transmembrane domain, and a lumenal catalytic domain. It belongs to glycosyltransferase family 29 and operates in the maturation of complex glycans on a wide range of glycoproteins and glycolipids. The enzyme’s substrates include glycoproteins such as mucins and the Fc region of immunoglobulin G, among others, affecting their stability, receptor interactions, and immune properties.

Biological roles of ST6GAL1 include regulation of cell–cell and cell–matrix interactions, modulation of immune cell trafficking, and influence on receptor and antibody functions through glycan remodeling. In physiology and disease, altered ST6GAL1 expression or activity has been observed in various cancers and inflammatory conditions, where changes in alpha-2,6-sialylation can impact tumor progression, metastasis, immune evasion, and therapeutic responses. ST6GAL1 thus plays a key part in the broader regulation of glycosylation-dependent processes in health and disease.