GALNTs transfer GalNAc to Mucins to form Tn antigens

Stable Identifier
Reaction [transition]
Homo sapiens
Addition of GalNAc to mucins to form the Tn antigen
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The family of UDP GalNAc:polypeptide N acetylgalactosaminyltransferases (GalNAc transferases, GALNTs) carry out the addition of N acetylgalactosamine on serine, threonine or possibly tyrosine residues on a wide variety of proteins, and most commonly associated with mucins (Wandall et al. 1997). This reaction takes place in the Golgi apparatus (Rottger et al. 1998). There are 20 known members of the GALNT family, 15 of which have been characterised and 5 candidate members which are thought to belong to this family based on sequence similarity (Bennett et al. 2012). The GALNT-family is classified as belonging to CAZy family GT27. The Tn antigen is the simplest possible amino acid–carbohydrate glycoconjugate and comprises a GalNAc α-O-linked to either serine or threonine. In normal mammalian mucins, GalNAc is substituted by Gal, GlcNAc, or GalNAc forming up to eight different core structures. The unsubstituted Tn antigen is often found in cancer and is associated with poor prognosis (Kamerling 2007).
Literature References
PubMed ID Title Journal Year
22183981 Control of mucin-type O-glycosylation: a classification of the polypeptide GalNAc-transferase gene family

Fritz, TA, Mandel, U, Bennett, EP, Tabak, LA, Gerken, TA, Clausen, H

Glycobiology 2012
9394011 Localization of three human polypeptide GalNAc-transferases in HeLa cells suggests initiation of O-linked glycosylation throughout the Golgi apparatus

Whitehouse, C, White, J, Bennett, EP, Olivo, JC, Röttger, S, Berger, EG, Nilsson, T, Stark, A, Wandall, HH, Clausen, H

J Cell Sci 1998
9295285 Substrate specificities of three members of the human UDP-N-acetyl-alpha-D-galactosamine:Polypeptide N-acetylgalactosaminyltransferase family, GalNAc-T1, -T2, and -T3

Burchell, J, Bennett, EP, Hassan, H, Taylor-Papadimitriou, J, Roepstorff, P, Hollingsworth, MA, Kristensen, AK, Nielsen, PA, Mirgorodskaya, E, Wandall, HH, Clausen, H

J Biol Chem 1997
Catalyst Activity

polypeptide N-acetylgalactosaminyltransferase activity of GALNTs [Golgi membrane]

Orthologous Events
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