Mutation of MyoD-Ser237 abolishes its up-regulation by c-Mos.
Recently we have shown that Mos could activate myogenic differentiation by promoting heterodimerisation of MyoD and E12 proteins. Here, we demonstrate that MyoD can be efficiently phosphorylated by in vitro kinase assay with purified Mos immunoprecipitated from transfected cells. Comparative two-dimensional tryptic phosphopeptide mapping combined with site-directed mutagenesis revealed that Mos phosphorylates MyoD on serine 237. Mutation of serine 237 to a non-phosphorylable alanine (MyoD-Ala237) abolished the positive regulation of MyoD by Mos following overexpression in proliferating 10T1/2 cells. Taken together, our data show that direct phosphorylation of MyoD-Ser237 by Mos plays a positive role in increasing MyoD activity during myoblast proliferation.
Pelpel
K
K
Laboratoire de Génétique Oncologique, UMR 1599, CNRS Institut Gustave Roussy, Villejuif, France.
Leibovitch
M
M
Fernandez
A
A
Leibovitch
S A
SA
D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D002460:Cell Line; D017124:Conserved Sequence / Q000235:genetics; D003402:Creatine Kinase / Q000235:genetics; D005347:Fibroblasts; D051379:Mice; D009154:Mutation / Q000235:genetics*; D017570:MyoD Protein / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D009928:Organ Specificity; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010449:Peptide Mapping; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D017231:Proto-Oncogene Proteins c-mos / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D014162:Transfection; D014357:Trypsin / Q000378:metabolism; D015854:Up-Regulation
D017570:MyoD Protein; D010446:Peptide Fragments; D011994:Recombinant Proteins; D010768:Phosphoserine; D012694:Serine; D017231:Proto-Oncogene Proteins c-mos; D003402:Creatine Kinase; D014357:Trypsin