title: N-acetylglucosaminyltransferase V modifies the signaling pathway of epidermal growth factor receptor.
abstract: Transfection of sense cDNA of N-acetylglucosamyltransferase V (GnTV-S) into human H7721 hepatocarcinoma cells resulted in an increase in the N-acetylglucosaminebeta1,6mannosealpha1,3- branch (GnT-V product) on the N-glycans of epidermal growth factor (EGF) receptor (EGFR), and promotion of its EGF binding and tyrosine autophosphorylation, but showed little effect on the expression of EGFR protein. The phosphorylation at T308, S473 and tyrosine residue(s) and the activity of protein kinase B (Akt/PKB) as well as the phosphorylation of p42/44 mitogen-activated protein kinase (MAPK) and MAPK kinase (MEK) before and after EGF stimulation were concomitantly increased. Conversely, in the antisense GnT-V (GnTV-AS)-transfected H7721 cells, all the results were the reverse of those with GnTV-S-transfected cells. After the cells were treated with 1-deoxymannojirimycin, an inhibitor of N-glycan processing at high mannose, or antibody against the extracellular glycan domain of EGFR, the differences in PKB activity, p42/44 MAPK and MEK phosphorylation among GnTV-S-, GnTV-AS- and mock-transfected cells were significantly attenuated. These findings indicate that the altered expression of GnT-V will change the glycan structure and function of EGFR, which may modify downstream signal transduction.
authors.affiliation: Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry, Shanghai Medical College, Fudan University, 200032, China.
authors.forename: P
authors.initials: P
authors.lastname: Guo
authors.forename: Q Y
authors.initials: QY
authors.lastname: Wang
authors.forename: H B
authors.initials: HB
authors.lastname: Guo
authors.forename: Z H
authors.initials: ZH
authors.lastname: Shen
authors.forename: H L
authors.initials: HL
authors.lastname: Chen
mesh_terms: D000906:Antibodies / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000276:immunology / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction / Q000502:physiology*; D014407:Tumor Cells, Cultured
chemical_list: D000906:Antibodies; D011518:Proto-Oncogene Proteins; D004815:Epidermal Growth Factor; D017351:N-Acetylglucosaminyltransferases; C052254:alpha-1,6-mannosylglycoprotein beta 1,6-N-acetylglucosaminyltransferase; D066246:ErbB Receptors; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases