Aurora B kinase and protein phosphatase 1 have opposing roles in modulating kinetochore assembly.
The outer kinetochore binds microtubules to control chromosome movement. Outer kinetochore assembly is restricted to mitosis, whereas the inner kinetochore remains tethered to centromeres throughout the cell cycle. The cues that regulate this transient assembly are unknown. We find that inhibition of Aurora B kinase significantly reduces outer kinetochore assembly in Xenopus laevis and human tissue culture cells, frog egg extracts, and budding yeast. In X. leavis M phase extracts, preassembled kinetochores disassemble after inhibiting Aurora B activity with either drugs or antibodies. Kinetochore disassembly, induced by Aurora B inhibition, is rescued by restraining protein phosphatase 1 (PP1) activity. PP1 is necessary for kinetochores to disassemble at the exit from M phase, and purified enzyme is sufficient to cause disassembly on isolated mitotic nuclei. These data demonstrate that Aurora B activity is required for kinetochore maintenance and that PP1 is necessary and sufficient to disassemble kinetochores. We suggest that Aurora B and PP1 coordinate cell cycle-dependent changes in kinetochore assembly though phosphorylation of kinetochore substrates.
Emanuele
Michael J
MJ
Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA.
Lan
Weijie
W
Jwa
Miri
M
Miller
Stephanie A
SA
Chan
Clarence S M
CS
Stukenberg
P Todd
PT
D000818:Animals; D064107:Aurora Kinase B; D064127:Aurora Kinases; D002453:Cell Cycle; D002455:Cell Division; D002467:Cell Nucleus / Q000502:physiology / Q000648:ultrastructure; D002478:Cells, Cultured; D002503:Centromere / Q000235:genetics; D004261:DNA Replication; D018386:Kinetochores / Q000201:enzymology / Q000648:ultrastructure*; D008297:Male; D008938:Mitosis; D054645:Protein Phosphatase 1 / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D013094:Spermatozoa / Q000502:physiology / Q000648:ultrastructure; D029867:Xenopus Proteins / Q000378:metabolism; D014982:Xenopus laevis
D029867:Xenopus Proteins; C576921:AURKB protein, human; D064107:Aurora Kinase B; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D054645:Protein Phosphatase 1