title: Down-regulation of hydrogen peroxide-induced PKC delta activation in N-acetylglucosaminyltransferase III-transfected HeLaS3 cells.
abstract: N-acetylglucosaminyltransferase III (GnT-III) is a key enzyme that inhibits the extension of N-glycans by introducing a bisecting N-acetylglucosamine residue. Our previous studies have shown that modification of N-glycans by GnT-III affects a number of intracellular signaling pathways. In this study, the effects of GnT-III on the cellular response to reactive oxygen species (ROS) were examined. We found that an overexpression of GnT-III suppresses H(2)O(2)-induced apoptosis in HeLaS3 cells. In the case of GnT-III transfectants, activation of Jun N-terminal kinase (JNK) following H(2)O(2) treatment was markedly reduced compared with control cells. Either the depletion of protein kinase C (PKC) by prolonged treatment with phorbol 12-myristate 13-acetate or the inhibition of PKC by the specific inhibitor H7 attenuated the H(2)O(2)-induced activation of JNK1 and apoptosis in control cells but not in the GnT-III transfectants. Furthermore, we found that H(2)O(2)-induced phosphorylation of PKC delta was markedly suppressed in GnT-III transfectants. Rottlerin, a specific inhibitor of PKC delta, significantly inhibited H(2)O(2)-induced activation of JNK1 in control cells, indicating that PKC delta is involved in the pathway. These findings suggest that the overexpression of GnT-III suppresses H(2)O(2)-induced activation of PKC delta-JNK1 pathway, resulting in inhibition of apoptosis.
authors.affiliation: Department of Biochemistry, Osaka University Graduate School of Medicine, B1, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yukinao
authors.initials: Y
authors.lastname: Shibukawa
authors.forename: Motoko
authors.initials: M
authors.lastname: Takahashi
authors.forename: Isabelle
authors.initials: I
authors.lastname: Laffont
authors.forename: Koichi
authors.initials: K
authors.lastname: Honke
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Taniguchi
mesh_terms: D004789:Enzyme Activation / Q000187:drug effects; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D008156:Luciferases / Q000235:genetics; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics* / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D051745:Protein Kinase C-delta; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D011993:Recombinant Fusion Proteins; D006861:Hydrogen Peroxide; D008156:Luciferases; D017351:N-Acetylglucosaminyltransferases; C054599:beta-1,4-mannosyl-glycoprotein beta-1,4-N-acetylglucosaminyltransferase; C497258:PRKCD protein, human; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases