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The stability of Fbw7α in M-phase requires its phosphorylation by PKC.
Zitouni, Sihem; Méchali, Francisca; Papin, Catherine; Choquet, Armelle; Roche, Daniel; Baldin, Véronique; Coux, Olivier; Bonne-Andrea, Catherine.
Afiliação
  • Zitouni S; Centre de Recherche de Biologie Cellulaire de Montpellier, CNRS, UMR 5237, Université de Montpellier, Montpellier, France.
  • Méchali F; Centre de Recherche de Biologie Cellulaire de Montpellier, CNRS, UMR 5237, Université de Montpellier, Montpellier, France.
  • Papin C; Institut de Génétique Humaine, CNRS, UMR 9002, Université de Montpellier, Montpellier, France.
  • Choquet A; Institut de Génomique Fonctionnelle, CNRS UMR 5203, Université de Montpellier, Montpellier, France.
  • Roche D; Centre de Recherche de Biologie Cellulaire de Montpellier, CNRS, UMR 5237, Université de Montpellier, Montpellier, France.
  • Baldin V; Institut de Biologie Computationnelle, LIRMM, CNRS, Université de Montpellier, Montpellier, France.
  • Coux O; Centre de Recherche de Biologie Cellulaire de Montpellier, CNRS, UMR 5237, Université de Montpellier, Montpellier, France.
  • Bonne-Andrea C; Centre de Recherche de Biologie Cellulaire de Montpellier, CNRS, UMR 5237, Université de Montpellier, Montpellier, France.
PLoS One ; 12(8): e0183500, 2017.
Article em En | MEDLINE | ID: mdl-28850619
Fbw7 is a tumor suppressor often deleted or mutated in human cancers. It serves as the substrate-recruiting subunit of a SCF ubiquitin ligase that targets numerous critical proteins for degradation, including oncoproteins and master transcription factors. Cyclin E was the first identified substrate of the SCFFbw7 ubiquitin ligase. In human cancers bearing FBXW7-gene mutations, deregulation of cyclin E turnover leads to its aberrant expression in mitosis. We investigated Fbw7 regulation in Xenopus eggs, which, although arrested in a mitotic-like phase, naturally express high levels of cyclin E. Here, we report that Fbw7α, the only Fbw7 isoform detected in eggs, is phosphorylated by PKC (protein kinase C) at a key residue (S18) in a manner coincident with Fbw7α inactivation. We show that this PKC-dependent phosphorylation and inactivation of Fbw7α also occurs in mitosis during human somatic cell cycles, and importantly is critical for Fbw7α stabilization itself upon nuclear envelope breakdown. Finally, we provide evidence that S18 phosphorylation, which lies within the intrinsically disordered N-terminal region specific to the α-isoform reduces the capacity of Fbw7α to dimerize and to bind cyclin E. Together, these findings implicate PKC in an evolutionarily-conserved pathway that aims to protect Fbw7α from degradation by keeping it transiently in a resting, inactive state.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Proteína Quinase C / Divisão Celular / Proteínas de Ciclo Celular / Ubiquitina-Proteína Ligases / Proteínas F-Box Tipo de estudo: Prognostic_studies Limite: Animals / Humans Idioma: En Revista: PLoS One Assunto da revista: CIENCIA / MEDICINA Ano de publicação: 2017 Tipo de documento: Article País de afiliação: França

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Proteína Quinase C / Divisão Celular / Proteínas de Ciclo Celular / Ubiquitina-Proteína Ligases / Proteínas F-Box Tipo de estudo: Prognostic_studies Limite: Animals / Humans Idioma: En Revista: PLoS One Assunto da revista: CIENCIA / MEDICINA Ano de publicação: 2017 Tipo de documento: Article País de afiliação: França