title: p53 localization at centrosomes during mitosis and postmitotic checkpoint are ATM-dependent and require serine 15 phosphorylation.
abstract: We recently demonstrated that the p53 oncosuppressor associates to centrosomes in mitosis and this association is disrupted by treatments with microtubule-depolymerizing agents. Here, we show that ATM, an upstream activator of p53 after DNA damage, is essential for p53 centrosomal localization and is required for the activation of the postmitotic checkpoint after spindle disruption. In mitosis, p53 failed to associate with centrosomes in two ATM-deficient, ataxiatelangiectasia-derived cell lines. Wild-type ATM gene transfer reestablished the centrosomal localization of p53 in these cells. Furthermore, wild-type p53 protein, but not the p53-S15A mutant, not phosphorylatable by ATM, localized at centrosomes when expressed in p53-null K562 cells. Finally, Ser15 phosphorylation of endogenous p53 was detected at centrosomes upon treatment with phosphatase inhibitors, suggesting that a p53 dephosphorylation step at centrosome contributes to sustain the cell cycle program in cells with normal mitotic spindles. When dissociated from centrosomes by treatments with spindle inhibitors, p53 remained phosphorylated at Ser15. AT cells, which are unable to phosphorylate p53, did not undergo postmitotic proliferation arrest after nocodazole block and release. These data demonstrate that ATM is required for p53 localization at centrosome and support the existence of a surveillance mechanism for inhibiting DNA reduplication downstream of the spindle assembly checkpoint
authors.affiliation: Istituto di Biologia e Patologia Molecolari Consiglio Nazionale delle Ricerche, 00185 Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Tritarelli
authors.forename: E
authors.initials: E
authors.lastname: Oricchio
authors.forename: M
authors.initials: M
authors.lastname: Ciciarello
authors.forename: R
authors.initials: R
authors.lastname: Mangiacasale
authors.forename: A
authors.initials: A
authors.lastname: Palena
authors.forename: P
authors.initials: P
authors.lastname: Lavia
authors.forename: S
authors.initials: S
authors.lastname: Soddu
authors.forename: E
authors.initials: E
authors.lastname: Cundari
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D002460:Cell Line; D018385:Centrosome / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins; D006801:Humans; D008938:Mitosis; D009154:Mutation / Q000235:genetics; D015739:Nocodazole / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism; D014404:Tubulin / Q000032:analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D014404:Tubulin; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D012694:Serine; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D015739:Nocodazole