Abstract
Heat shock protein 70 (HSP70) has been shown to be a substrate of Polo-like kinase 1 (PLK1), and it prevents cells arrested in mitosis by arsenic trioxide (ATO) from dying. Here, we report that HSP70 participates in ATO-induced spindle elongation, which interferes with mitosis progression. Our results demonstrate that HSP70 and PLK1 colocalize at the centrosome in ATO-arrested mitotic cells. HSP70 located at the centrosome was found to be phosphorylated by PLK1 at Ser⁶³¹ and Ser⁶³³. Moreover, unlike wild-type HSP70 (HSP70(wt)) and its phosphomimetic mutant (HSP70(SS631,633DD)), a phosphorylation-resistant mutant of HSP70 (HSP70(SS631,633AA)) failed to localize at the centrosome. ATO-induced spindle elongation was abolished in cells overexpressing HSP70(SS631,633AA). Conversely, mitotic spindles in cells ectopically expressing HSP70(SS631,633DD) were more resistant to nocodazole-induced depolymerization than in those expressing HSP70(wt) or HSP70(SS631,633AA). In addition, inhibition of PLK1 significantly reduced HSP70 phosphorylation and induced early onset of apoptosis in ATO-arrested mitotic cells. Taken together, our results indicate that PLK1-mediated phosphorylation and centrosomal localization of HSP70 may interfere with spindle dynamics and prevent apoptosis of ATO-arrested mitotic cells.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Substitution
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Apoptosis / drug effects
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Arsenic Trioxide
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Arsenicals
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Carcinogens, Environmental / toxicity*
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Cell Cycle Proteins / antagonists & inhibitors
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Centrosome / drug effects*
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Centrosome / metabolism
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Gene Silencing
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HEK293 Cells
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HSP70 Heat-Shock Proteins / antagonists & inhibitors
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HSP70 Heat-Shock Proteins / genetics
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HSP70 Heat-Shock Proteins / metabolism*
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HeLa Cells
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Humans
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Mitosis / drug effects
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Mitosis Modulators / toxicity*
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Mutant Proteins / antagonists & inhibitors
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Mutant Proteins / metabolism
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Oxides / toxicity*
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Phosphorylation / drug effects
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Polo-Like Kinase 1
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Protein Processing, Post-Translational / drug effects
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Protein Serine-Threonine Kinases / antagonists & inhibitors
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism*
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Protein Transport / drug effects
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Proto-Oncogene Proteins / antagonists & inhibitors
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism*
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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Spindle Apparatus / drug effects*
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Spindle Apparatus / metabolism
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Tubulin Modulators / pharmacology
Substances
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Arsenicals
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Carcinogens, Environmental
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Cell Cycle Proteins
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HSP70 Heat-Shock Proteins
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Mitosis Modulators
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Mutant Proteins
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Oxides
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Proto-Oncogene Proteins
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Recombinant Proteins
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Tubulin Modulators
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Protein Serine-Threonine Kinases
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Arsenic Trioxide