title: Phosphorylation and stabilization of TAp63gamma by IkappaB kinase-beta.
abstract: Post-translational modification of the p53 family members is key to their regulation. Here we report the phosphorylation of TAp63gamma, but not DeltaNp63gamma, by IkappaB kinase beta (IKKbeta). Activation of IKKbeta by gamma radiation or tumor necrosis factor-alpha led to increased TAp63gamma protein levels in cells. IKKbeta, but not its kinase-defective mutant IKKbeta-K44A, led to this observed stabilization of TAp63gamma. This stabilization of TAp63gamma in response to gamma radiation was significantly decreased in the absence of IKKbeta. Phosphorylation of TAp63gamma blocks ubiquitylation and possible degradation of this protein. We postulate that phosphorylation of TAp63gamma by IKKbeta stabilizes the TAp63gamma protein by blocking ubiquitylation-dependent degradation of this protein.
authors.affiliation: Center for Hematologic Malignancies, Oregon Health & Science University Cancer Institute, Oregon Health and Science University, Portland, Oregon 97239-3098, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: MacPartlin
authors.forename: Shelya X
authors.initials: SX
authors.lastname: Zeng
authors.forename: Hua
authors.initials: H
authors.lastname: Lu
mesh_terms: D019943:Amino Acid Substitution; D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000235:genetics / Q000528:radiation effects; D005720:Gamma Rays; D006801:Humans; D051550:I-kappa B Kinase / Q000235:genetics / Q000378:metabolism*; D020125:Mutation, Missense; D010766:Phosphorylation / Q000528:radiation effects; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination / Q000502:physiology* / Q000528:radiation effects
chemical_list: C115051:TP63 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D051550:I-kappa B Kinase