First Author | Fiete D | Year | 2012 |
Journal | J Biol Chem | Volume | 287 |
Issue | 34 | Pages | 29204-12 |
PubMed ID | 22722940 | Mgi Jnum | J:345467 |
Mgi Id | MGI:6861934 | Doi | 10.1074/jbc.M112.371880 |
Citation | Fiete D, et al. (2012) Peptide-specific transfer of N-acetylgalactosamine to O-linked glycans by the glycosyltransferases beta1,4-N-acetylgalactosaminyl transferase 3 (beta4GalNAc-T3) and beta4GalNAc-T4. J Biol Chem 287(34):29204-12 |
abstractText | N- and O-linked oligosaccharides on pro-opiomelanocortin both bear the unique terminal sequence SO(4)-4-GalNAcbeta1,4GlcNAcbeta. We previously demonstrated that protein-specific transfer of GalNAc to N-linked oligosaccharides on glycoprotein substrates is dependent on the presence of both an oligosaccharide acceptor and a peptide recognition motif consisting of a cluster of basic amino acids. We characterized how two beta1,4-N-acetylgalactosaminyltransferases, beta4GalNAc-T3 and beta4GalNAc-T4, require the presence of both the peptide recognition motif and the N-linked oligosaccharide acceptors to transfer GalNAc in beta1,4-linkage to GlcNAc in vivo and in vitro. We now show that beta4GalNAc-T3 and beta4GalNAc-T4 are able to utilize the same peptide motif to selectively add GalNAc to beta1,6-linked GlcNAc in core 2 O-linked oligosaccharide structures to form Galbeta1,3(GalNAcbeta1,4GlcNAcbeta1,6)GalNAcalphaSer/Thr. The beta1,4-linked GalNAc can be further modified with 4-linked sulfate by either GalNAc-4-sulfotransferase 1 (GalNAc-4-ST1) (CHST8) or GalNAc-4-ST2 (CHST9) or with alpha2,6-linked N-acetylneuraminic acid by alpha2,6-sialyltransferase 1 (ST6Gal1), thus generating a family of unique GalNAcbeta1,4GlcNAcbeta (LacdiNAc)-containing structures on specific glycoproteins. |