Abstract
p53 is present at low levels in unstressed cells. Numerous cellular insults, including DNA damage and microtubule disruption, elevate p53 protein levels. Phosphorylation of p53 is proposed to be important for p53 stabilization and activation after genotoxic stress; however, p53 phosphorylation after microtubule disruption has not been analysed. The goal of the current study was to determine if p53 phosphorylation increases after microtubule disruption, and if so, to identify specific p53 residues necessary for microtubule inhibitor-induced phosphorylation. Two dimensional gel analyses demonstrated that the number of p53 phospho-forms in cells increased after treatment with microtubule inhibitors (MTIs) and that the pattern of p53 phosphorylation was distinct from that observed after DNA damage. p53 phosphorylation also varied in a MTI-dependent manner, as Taxol and Vincristine induced more p53 phospho-forms than nocodazole. Further, MTI treatment increased phosphorylation of p53 on serine-15 in epithelial tumor cells. In contrast, serine-15 phosphorylation of p53 did not increase in MTI-treated primary cultures of human fibroblasts. Analysis of ectopically expressed p53 phospho-mutant proteins from Taxol- and nocodazole-treated cells indicated that multiple p53 amino terminal residues, including serine-15 and threonine-18, were required for Taxol-mediated phosphorylation of p53. Taken together, the results of this study demonstrate that distinct p53 phospho-forms are induced by MTI treatment as compared to DNA damage and that p53 phosphorylation is mediated in a MTI- and cell-specific manner. Oncogene (2001) 20, 113 - 124.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Antineoplastic Agents / pharmacology*
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Ataxia Telangiectasia / enzymology
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Ataxia Telangiectasia / genetics
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Ataxia Telangiectasia Mutated Proteins
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Cell Cycle Proteins
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Cell Line
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DNA-Binding Proteins
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Dose-Response Relationship, Drug
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Doxorubicin / pharmacology
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Humans
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Microtubules / drug effects*
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Microtubules / metabolism*
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Microtubules / radiation effects
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Mutagenesis, Site-Directed
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Paclitaxel / pharmacology
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Peptide Fragments / analysis
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Peptide Fragments / genetics
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Peptide Fragments / radiation effects
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Phosphoproteins / genetics
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Phosphoproteins / metabolism
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Phosphoproteins / radiation effects
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Phosphorylation / drug effects
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Phosphorylation / radiation effects
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Protein Isoforms / genetics
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Protein Isoforms / metabolism
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Protein Isoforms / radiation effects
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Protein Serine-Threonine Kinases / deficiency
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / physiology
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Serine / genetics
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Serine / metabolism
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Threonine / genetics
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Threonine / metabolism
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Tumor Cells, Cultured
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism*
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Tumor Suppressor Protein p53 / radiation effects
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Tumor Suppressor Proteins
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Vincristine / pharmacology
Substances
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Antineoplastic Agents
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Cell Cycle Proteins
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DNA-Binding Proteins
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Peptide Fragments
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Phosphoproteins
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Protein Isoforms
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Tumor Suppressor Protein p53
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Tumor Suppressor Proteins
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Threonine
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Serine
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Vincristine
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Doxorubicin
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ATM protein, human
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Ataxia Telangiectasia Mutated Proteins
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Protein Serine-Threonine Kinases
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Paclitaxel