title: p53 is localized to a sub-nucleolar compartment after proteasomal inhibition in an energy-dependent manner.
abstract: The tumor suppressor p53 is activated in response to many forms of cellular stress leading to cell cycle arrest, senescence or apoptosis. Appropriate sub-cellular localization is essential for modulating p53 function. We recently showed that p53 localizes to the nucleolus after proteasome inhibition with MG132 and this localization requires sequences within its carboxyl terminus. In the present study, we found that after treatment with MG132, p53 associates with a discrete sub-nucleolar component, the fibrillar center (FC), a region mainly enriched with RNA polymerase I. Moreover, we now demonstrate that this localization is an energy-dependent process as reduction of ATP levels prevents nucleolar localization. In addition, p53 sub-nucleolar accumulation is abolished when cells are subjected to various types of genotoxic stress. Furthermore, we show that monoubiquitination of p53, which causes it to localize to the cytoplasm and nucleoplasm, does not prevent the association of p53 with the nucleolus after MG132 treatment. Importantly, we demonstrate that p53 nucleolar association occurs in lung and bladder carcinomas.
authors.affiliation: Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
authors.forename: Orit
authors.initials: O
authors.lastname: Karni-Schmidt
authors.forename: Andrew
authors.initials: A
authors.lastname: Zupnick
authors.forename: Mirela
authors.initials: M
authors.lastname: Castillo
authors.forename: Aqeel
authors.initials: A
authors.lastname: Ahmed
authors.forename: Tulio
authors.initials: T
authors.lastname: Matos
authors.forename: Philippe
authors.initials: P
authors.lastname: Bouvet
authors.forename: Carlos
authors.initials: C
authors.lastname: Cordon-Cardo
authors.forename: Carol
authors.initials: C
authors.lastname: Prives
mesh_terms: D000595:Amino Acid Sequence; D002277:Carcinoma / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D008175:Lung Neoplasms / Q000378:metabolism*; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D061988:Proteasome Inhibitors; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D054875:Ubiquitination; D001749:Urinary Bladder Neoplasms / Q000378:metabolism*
chemical_list: D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D050505:Mutant Proteins; D061988:Proteasome Inhibitors; D016159:Tumor Suppressor Protein p53; D025801:Ubiquitin; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde