This entry represents a Family 2/fringe-like glycosyltransferase domain that is found in DNA-modifying proteins of phages and eukaryotes [1]. The name TAGT is derived from phage versions that are operonic with TET/JBP-dioxygenases [1]. In kinetoplastids, the TAGT enzyme catalyses the second step in forming the hypermodified base J [1,2]. The vertebrate GREB1 protein appears to catalyse the O-GlcNAcylation of ERalpha, protecting it from ubiquitination-based degradation [3].

1: Computational identification of novel biochemical systems involved in oxidation, glycosylation and other complex modifications of bases in DNA. Iyer LM, Zhang D, Burroughs AM, Aravind L; Nucleic Acids Res. 2013;41:7635-7655. PMID:23814188

2: Identification of the glucosyltransferase that converts hydroxymethyluracil to base J in the trypanosomatid genome. Bullard W, Lopes da Rosa-Spiegler J, Liu S, Wang Y, Sabatini R; J Biol Chem. 2014;289:20273-20282. PMID:24891501

3: GREB1: An evolutionarily conserved protein with a glycosyltransferase domain links ERalpha glycosylation and stability to cancer. Shin EM, Huynh VT, Neja SA, Liu CY, Raju A, Tan K, Tan NS, Gunaratne J, Bi X, Iyer LM, Aravind L, Tergaonkar V; Sci Adv. 2021; [Epub ahead of print] PMID:33731348