title: Regulation of c-Myc through phosphorylation at Ser-62 and Ser-71 by c-Jun N-terminal kinase.
abstract: The expression of c-myc promotes cell proliferation and also sensitizes cells to various extracellular apoptotic stimuli. However, signal pathways regulating the function of Myc proteins during apoptosis are unknown. c-Jun N-terminal kinase (JNK) is activated by various apoptotic stimuli, but neither the target molecule(s) or the action of JNK has been identified in Myc-mediated apoptosis. Here, we found that JNK selectively interacted with, and phosphorylated, c-Myc at Ser-62 and Ser-71 as confirmed with phospho-c-Myc-specific antibodies. Interestingly, dominant negative mutant JNK(APF) impaired the c-Myc-dependent apoptosis, but not mutated c-Myc (S62A/S71A)-dependent apoptosis triggered by UV irradiation. Furthermore, c-Myc (S62A/S71A)-expressing NIH3T3 cells were not sensitized like wild type c-Myc-expressing NIH3T3 cells to JNK-activating apoptotic stimuli, such as UV and Taxol. These results indicate that the JNK pathway is selectively involved in the c-Myc-mediated apoptosis and that the apoptotic function of c-Myc is directly regulated by JNK pathway through phosphorylation at Ser-62 and Ser-71.
authors.affiliation: Biophysics Division, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Noguchi
authors.forename: C
authors.initials: C
authors.lastname: Kitanaka
authors.forename: H
authors.initials: H
authors.lastname: Yamana
authors.forename: A
authors.initials: A
authors.lastname: Kokubu
authors.forename: T
authors.initials: T
authors.lastname: Mochizuki
authors.forename: Y
authors.initials: Y
authors.lastname: Kuchino
mesh_terms: D016475:3T3 Cells; D000818:Animals; D017209:Apoptosis; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016296:Mutagenesis; D017239:Paclitaxel / Q000494:pharmacology; D010766:Phosphorylation; D011485:Protein Binding; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D015398:Signal Transduction; D014466:Ultraviolet Rays
chemical_list: D016271:Proto-Oncogene Proteins c-myc; D011993:Recombinant Fusion Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D017239:Paclitaxel