Protein sialyltransferase specifically expressed in goblet cells that plays a key role in intestinal host-commensal homeostasis . Conjugates sialic acid with an alpha-2-6 linkage to N-acetylgalactosamine (GalNAc) glycan chains linked to serine or threonine in glycoproteins (, ). Catalyzes the formation of the sialyl-Tn (S-Tn) antigen, an antigen found in intestinal goblet cells, as well as ulcerative colitis (UC) and various cancers (, ). Protein sialylation in globlet cells is essential for mucus integrity and is required to protect the intestinal mucus against excessive bacterial proteolytic degradation .
Subcellular locations: Golgi apparatus membrane
Expression is restricted to the gastrointestinal tract . Highly expressed in goblet cells . Also expressed in various tumor cells .