title: PARP co-activates B-MYB through enhanced phosphorylation at cyclin/cdk2 sites.
abstract: PARP is a multifunctional protein that can affect genome stability, transcription control, telomere length and cell death. Recently we have reported that PARP binds to and enhances B-MYB transactivating potential. B-MYB is a potentially oncogenic transcription factor involved in mammalian cell proliferation, survival and differentiation. B-MYB gene expression is growth regulated and B-MYB protein is phosphorylated during S phase by cyclin A or E/cdk2 kinase, resulting in augmented transactivating potential. Here we show that PARP induces phosphorylation of B-MYB protein at cdk2 phosphorylation sites, since a B-MYB protein with mutated cdk2 phosphorylation sites is refractory to PARP-induced phosphorylation and co-activation in mammalian cells. We propose that PARP functions as a B-MYB co-factor by promoting cyclin/cdk2-dependent B-MYB phosphorylation. These results highlight a novel role for PARP as a factor that integrates cyclin-dependent kinases signaling with gene transcription.
authors.affiliation: Department of Oncology and Neurosciences, Section of Medical Oncology, Universita' G. D'Annunzio, 66100 Chieti, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Santilli
authors.forename: M N
authors.initials: MN
authors.lastname: Cervellera
authors.forename: T K
authors.initials: TK
authors.lastname: Johnson
authors.forename: R E
authors.initials: RE
authors.lastname: Lewis
authors.forename: S
authors.initials: S
authors.lastname: Iacobelli
authors.forename: A
authors.initials: A
authors.lastname: Sala
mesh_terms: D042846:CDC2-CDC28 Kinases; D018797:Cell Cycle Proteins; D002460:Cell Line; D002478:Cells, Cultured; D019925:Cyclin A / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D016213:Cyclins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006801:Humans; D009154:Mutation; D010766:Phosphorylation; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D015534:Trans-Activators / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D018797:Cell Cycle Proteins; D019925:Cyclin A; D016213:Cyclins; D004268:DNA-Binding Proteins; C064352:MYBL2 protein, human; D015534:Trans-Activators; D011065:Poly(ADP-ribose) Polymerases; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases