title: HSP70 colocalizes with PLK1 at the centrosome and disturbs spindle dynamics in cells arrested in mitosis by arsenic trioxide.
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.
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan.
authors.forename: Yu-Ju
authors.initials: YJ
authors.lastname: Chen
authors.forename: Kuo-Chu
authors.initials: KC
authors.lastname: Lai
authors.forename: Hsiao-Hui
authors.initials: HH
authors.lastname: Kuo
authors.forename: Lu-Ping
authors.initials: LP
authors.lastname: Chow
authors.forename: Ling-Huei
authors.initials: LH
authors.lastname: Yih
authors.forename: Te-Chang
authors.initials: TC
authors.lastname: Lee
mesh_terms: D019943:Amino Acid Substitution; D017209:Apoptosis / Q000187:drug effects; D000077237:Arsenic Trioxide; D001152:Arsenicals; D002274:Carcinogens, Environmental / Q000633:toxicity*; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018385:Centrosome / Q000187:drug effects* / Q000378:metabolism; D020868:Gene Silencing; D057809:HEK293 Cells; D018840:HSP70 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis / Q000187:drug effects; D050258:Mitosis Modulators / Q000633:toxicity*; D050505:Mutant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D010087:Oxides / Q000633:toxicity*; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D008941:Spindle Apparatus / Q000187:drug effects* / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology; D000097869:Polo-Like Kinase 1
chemical_list: D000077237:Arsenic Trioxide; D001152:Arsenicals; D002274:Carcinogens, Environmental; D018797:Cell Cycle Proteins; D018840:HSP70 Heat-Shock Proteins; D050258:Mitosis Modulators; D050505:Mutant Proteins; D010087:Oxides; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D050257:Tubulin Modulators; D000097869:Polo-Like Kinase 1