Uncoupling anaphase-promoting complex/cyclosome activity from spindle assembly checkpoint control by deregulating polo-like kinase 1.
Polo-like kinase 1 (Plk1) plays a role in numerous events in mitosis, but how the multiple functions of Plk1 are separated is poorly understood. We studied regulation of Plk1 through two putative phosphorylation residues, Ser-137 and Thr-210. Using phospho-specific antibodies, we found that Thr-210 phosphorylation precedes Ser-137 phosphorylation in vivo, the latter occurring specifically in late mitosis. We show that expression of two activating mutants of these residues, S137D and T210D, results in distinct mitotic phenotypes. Whereas expression of both phospho-mimicking mutants as well as of the double mutant leads to accelerated mitotic entry, further progression through mitosis is dramatically different: the T210D mutant causes a spindle assembly checkpoint-dependent delay, whereas the expression of the S137D mutant or the double mutant results in untimely activation of the anaphase-promoting complex/cyclosome (APC/C) and frequent mitotic catastrophe. Using nonphosphorylatable Plk1-S137A and Plk1-T210A mutants, we show that both sites contribute to proper mitotic progression. Based on these observations, we propose that Plk1 function is altered at different stages of mitosis through consecutive posttranslational events, e.g., at Ser-137 and Thr-210. Furthermore, our data show that uncontrolled Plk1 activation can uncouple APC/C activity from spindle assembly checkpoint control.
van de Weerdt
Barbara C M
BC
Division of Molecular Biology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
van Vugt
Marcel A T M
MA
Lindon
Catherine
C
Kauw
Jos J W
JJ
Rozendaal
Marieke J
MJ
Klompmaker
Rob
R
Wolthuis
Rob M F
RM
Medema
René H
RH
D064173:Anaphase-Promoting Complex-Cyclosome; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D006801:Humans; D008938:Mitosis / Q000235:genetics / Q000502:physiology*; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology*; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering / Q000235:genetics; D012694:Serine / Q000378:metabolism; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism*; D000097869:Polo-Like Kinase 1
D064173:Anaphase-Promoting Complex-Cyclosome; D018797:Cell Cycle Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D012694:Serine; D013912:Threonine; D043743:Ubiquitin-Protein Ligase Complexes; D000097869:Polo-Like Kinase 1