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Gene Review

MGAT5  -  mannosyl (alpha-1,6-)-glycoprotein beta-1...

Homo sapiens

Synonyms: Alpha-1,6-mannosylglycoprotein 6-beta-N-acetylglucosaminyltransferase A, Alpha-mannoside beta-1,6-N-acetylglucosaminyltransferase, GGNT5, GNT-V, GNT-VA, ...


This gene encodes mannosyl (alpha-1,6-)-glycoprotein beta-1,6-N-acetyl-glucosaminyltransferase, a glycosyltransferase involved in the synthesis of protein-bound and lipid-bound oligosaccharides. Alterations of the oligosaccharides on cell surface glycoproteins cause significant changes in the adhesive or migratory behavior of a cell. Increase in the encoded protein's activity may correlate with the progression of invasive malignancies. [provided by RefSeq]


Catalyzes the addition of N-acetylglucosamine in beta 1-6 linkage to the alpha-linked mannose of biantennary N-linked oligosaccharides. It is one of the most important enzymes involved in the regulation of the biosynthesis of glycoprotein oligosaccharides.


Disease relevance of MGAT5


High impact information on MGAT5


Biological context of MGAT5

  • Elevated activity and mRNA levels could be inhibited by blocking cell proliferation with herbimycin A, demonstrating that Src kinase activity can regulate GlcNAc-T V expression [2].
  • This stimulation by src could be antagonized by co-transfection with a dominant-negative mutant of the Raf kinase, suggesting the involvement of Ets transcription factors in the regulation of GlcNAc-T V gene expression [2].
  • Furthermore, Mgat5 glycan products stimulated membrane ruffling and phosphatidylinositol 3 kinase-protein kinase B activation, fueling a positive feedback loop that amplified oncogene signaling and tumor growth in vivo [1].
  • We describe a new phenotype of wide occurrence in human cancer: expression of coarse vesicles rich in beta1,6-branched oligosaccharides. beta1,6-branching, catalyzed by GNT-V, is associated with metastasis and predicts poor survival in primary human breast and colon carcinomas [4].
  • Promoter/reporter experiments showed that her-2/neu stimulates transcription from the human GlcNAc-T V promoter and that the her-2/neu response element was located about 400 bp 5' of the transcription initiation site and includes three Ets transcription factor binding sequences [5].

Anatomical context of MGAT5

  • By contrast, a lectin-resistant BHK cell line selected for its ability to grow in high levels of L-phytohemagglutinin, LP3.3, is characterized by a specific decrease in its GlcNAc-T V activity [6].
  • When extracts of Lec8 CHO cells were used as acceptors, GlcNAc-T V preferentially transferred to LAMPs, and only low level transfer was observed to other cell-derived glycoproteins, thus demonstrating specificity of GlcNAc-T V toward native glycoprotein acceptors [7].
  • Mv1Lu type II alveolar cells transfected with Golgi beta1,6 N-acetylglucosaminyltransferase V (Mgat5), enhancing the polylactosamine content of complex-type N-glycans, exhibit stable expression of MLBs whose formation requires lysosomal proteolysis within dense autophagic vacuoles [8].
  • GlcNAc beta 1-2(4,6-di-O-methyl-)Man alpha 1-6Glc beta-pnp was found to be an inhibitor of GlcNAc-T V from hamster kidney, hen oviduct microsomes and acute and chronic myeloid leukaemia leukocytes [9].

Associations of MGAT5 with chemical compounds

  • These results demonstrate that the mechanism of glycoprotein-specific branching by GlcNAc-T V is determined primarily by its accessibility to available bi/triantennary oligosaccharides on glycoproteins and not by its recognition of peptide determinants or conformation-specific determinants [7].
  • The formation of tri- and tetraantennary complex-type N-linked oligosaccharides in animal glycoproteins is partly regulated by UDP-N-acetylglucosamine:beta-6-D-mannoside beta-1,6-N-acetylglucosaminyltransferase (EC (GlcNAc-T V), which generates 2,6-branched mannose [7].
  • In Mv1Lu cells treated with the NPC-mimicking drug U18666A, cholesterol-rich MLBs accumulate independently of both Mgat5 expression and lysosomal proteolysis [8].
  • The enzymatic mechanisms of the above changes were revealed in further study to involve the decrease of N-acetylglucosaminyl-transferase V and core alpha-1,6-fucosyltransferase by retinoic acid [10].
  • Four analogs of trisaccharide 3 where OH-3" and OH-6" were replaced, independently, by NH2 and NHAc groups, were prepared by multi-step chemical synthesis and kinetically evaluated as substrates for GlcNAc T-V from hamster kidney [11].

Other interactions of MGAT5


  1. Suppression of tumor growth and metastasis in Mgat5-deficient mice. Granovsky, M., Fata, J., Pawling, J., Muller, W.J., Khokha, R., Dennis, J.W. Nat. Med. (2000) [Pubmed]
  2. Transcriptional regulation of N-acetylglucosaminyltransferase V by the src oncogene. Buckhaults, P., Chen, L., Fregien, N., Pierce, M. J. Biol. Chem. (1997) [Pubmed]
  3. Negative regulation of T-cell activation and autoimmunity by Mgat5 N-glycosylation. Demetriou, M., Granovsky, M., Quaggin, S., Dennis, J.W. Nature (2001) [Pubmed]
  4. Beta1,6-branched oligosaccharides and coarse vesicles: a common, pervasive phenotype in melanoma and other human cancers. Handerson, T., Pawelek, J.M. Cancer Res. (2003) [Pubmed]
  5. The her-2/neu oncogene stimulates the transcription of N-acetylglucosaminyltransferase V and expression of its cell surface oligosaccharide products. Chen, L., Zhang, W., Fregien, N., Pierce, M. Oncogene (1998) [Pubmed]
  6. Regulation of N-acetylglucosaminyltransferase V activity. Kinetic comparisons of parental, Rous sarcoma virus-transformed BHK, and L-phytohemagglutinin-resistant BHK cells using synthetic substrates and an inhibitory substrate analog. Palcic, M.M., Ripka, J., Kaur, K.J., Shoreibah, M., Hindsgaul, O., Pierce, M. J. Biol. Chem. (1990) [Pubmed]
  7. Modification of glycoproteins by N-acetylglucosaminyltransferase V is greatly influenced by accessibility of the enzyme to oligosaccharide acceptors. Do, K.Y., Fregien, N., Pierce, M., Cummings, R.D. J. Biol. Chem. (1994) [Pubmed]
  8. The lipid composition of autophagic vacuoles regulates expression of multilamellar bodies. Lajoie, P., Guay, G., Dennis, J.W., Nabi, I.R. J. Cell. Sci. (2005) [Pubmed]
  9. Substrate specificity and inhibition of UDP-GlcNAc:GlcNAc beta 1-2Man alpha 1-6R beta 1,6-N-acetylglucosaminyltransferase V using synthetic substrate analogues. Brockhausen, I., Reck, F., Kuhns, W., Khan, S., Matta, K.L., Meinjohanns, E., Paulsen, H., Shah, R.N., Baker, M.A., Schachter, H. Glycoconj. J. (1995) [Pubmed]
  10. Effect of retinoic acid on the structure of N-glycans on the surface of human hepatocarcinoma cells and its enzymatic mechanism. Chen, H.L., Dong, S.C., Ju, T.Z., Yang, X.P. J. Cancer Res. Clin. Oncol. (1995) [Pubmed]
  11. Key involvement of all three GlcNAc hydroxyl groups in the recognition of beta-D-GlcpNAc-(1-->2)-alpha-D-Manp-(1-->6)-beta-D-Glcp-OR by N-acetylglucosaminyltransferase-V. Kanie, O., Crawley, S.C., Palcic, M.M., Hindsgaul, O. Bioorg. Med. Chem. (1994) [Pubmed]
  12. Growth-associated glycosylation of transferrin secreted by HepG2 cells. Hahn, T.J., Goochee, C.F. J. Biol. Chem. (1992) [Pubmed]
  13. Identification of target proteins of N-acetylglucosaminyl transferase V in human colon cancer and implications of protein tyrosine phosphatase kappa in enhanced cancer cell migration. Kim, Y.S., Kang, H.Y., Kim, J.Y., Oh, S., Kim, C.H., Ryu, C.J., Miyoshi, E., Taniguchi, N., Ko, J.H. Proteomics (2006) [Pubmed]
  14. Identification of target proteins of N-acetylglucosaminyl-transferase V and fucosyltransferase 8 in human gastric tissues by glycomic approach. Kim, Y.S., Hwang, S.Y., Oh, S., Sohn, H., Kang, H.Y., Lee, J.H., Cho, E.W., Kim, J.Y., Yoo, J.S., Kim, N.S., Kim, C.H., Miyoshi, E., Taniguchi, N., Ko, J.H. Proteomics (2004) [Pubmed]
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