Polo-like kinase-1 is required for bipolar spindle formation but is dispensable for anaphase promoting complex/Cdc20 activation and initiation of cytokinesis.
Polo-like kinase-1 (Plk1) performs multiple essential functions during the cell cycle. Here we show that human Plk1-deficient cells are unable to separate their centrosomes, fail to form a bipolar spindle, and undergo a Mad2/BubR1-dependent prometaphase arrest. However, electron microscopy demonstrates that kinetochore-microtubule interactions can be established in cells lacking Plk1. In addition, co-depletion of Plk1 and survivin allows mitotic exit. This indicates that Plk1 depletion does not prevent microtubule attachment, but specifically interferes with the generation of tension, as a consequence of a failure to form a bipolar spindle. Moreover, we find that after silencing of the spindle assembly checkpoint, degradation of cyclin B1 is unaffected in cells lacking Plk1. These data indicate that activation of the anaphase promoting complex or cyclosome (APC/C)-Cdc20 complex that is under control of the spindle assembly checkpoint does not require Plk1 activity. Finally, we find that translocation of chromosome passengers and initiation of cleavage furrow ingression is unaffected in cells depleted of Plk1. Thus, our data confirm an important role of Plk1 in bipolar spindle formation, and also demonstrate that Plk1 is dispensable for APC/C-Cdc20 activation and the initiation of cytokinesis.
van Vugt
Marcel A T M
MA
Division of Molecular Biology, H8, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
van de Weerdt
Barbara C M
BC
Vader
Gerben
G
Janssen
Hans
H
Calafat
Jero
J
Klompmaker
Rob
R
Wolthuis
Rob M F
RM
Medema
René H
RH
D000705:Anaphase; D002130:Calcium Phosphates / Q000737:chemistry; D064199:Cdc20 Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002455:Cell Division; D045744:Cell Line, Tumor; D018385:Centrosome / Q000648:ultrastructure; D002875:Chromosomes / Q000648:ultrastructure; D019926:Cyclin B / Q000378:metabolism; D056744:Cyclin B1; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D018386:Kinetochores / Q000648:ultrastructure; D008164:Luminescent Proteins / Q000378:metabolism; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000648:ultrastructure; D008938:Mitosis; D010957:Plasmids / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D034622:RNA Interference; D008941:Spindle Apparatus; D013936:Thymidine / Q000737:chemistry; D013997:Time Factors; D014162:Transfection; D000097869:Polo-Like Kinase 1
D002130:Calcium Phosphates; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D019926:Cyclin B; D056744:Cyclin B1; D049452:Green Fluorescent Proteins; D006657:Histones; D008164:Luminescent Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D013936:Thymidine; D000097869:Polo-Like Kinase 1; C534699:CCNB1 protein, human; C577488:CDC20 protein, human; C020243:calcium phosphate