Direct binding between BubR1 and B56-PP2A phosphatase complexes regulate mitotic progression.
BubR1 is a central component of the spindle assembly checkpoint that inhibits progression into anaphase in response to improper kinetochore-microtubule interactions. In addition, BubR1 also helps stabilize kinetochore-microtubule interactions by counteracting the Aurora B kinase but the mechanism behind this is not clear. Here we show that BubR1 directly binds to the B56 family of protein phosphatase 2A (PP2A) regulatory subunits through a conserved motif that is phosphorylated by cyclin-dependent kinase 1 (Cdk1) and polo-like kinase 1 (Plk1). Two highly conserved hydrophobic residues surrounding the serine 670 Cdk1 phosphorylation site are required for B56 binding. Mutation of these residues prevents the establishment of a proper metaphase plate and delays cells in mitosis. Furthermore, we show that phosphorylation of serines 670 and 676 stimulates the binding of B56 to BubR1 and that BubR1 targets a pool of B56 to kinetochores. Our data suggest that BubR1 counteracts Aurora B kinase activity at improperly attached kinetochores by recruiting B56-PP2A phosphatase complexes.
The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 2200 Copenhagen, Denmark.
Thomas
T
Kruse
Gang
G
Zhang
Marie Sofie Yoo
MS
Larsen
Tiziana
T
Lischetti
Werner
W
Streicher
Tine
T
Kragh Nielsen
Sara Petersen
SP
Bjørn
Jakob
J
Nilsson
D016203:CDC2 Protein Kinase / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D002850:Chromatography, Gel; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D008856:Microscopy, Fluorescence; D008938:Mitosis / Q000235:genetics / Q000502:physiology*; D010766:Phosphorylation; D011485:Protein Binding; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D000097869:Polo-Like Kinase 1
D016203:CDC2 Protein Kinase; D018797:Cell Cycle Proteins; D054648:Protein Phosphatase 2; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D000097869:Polo-Like Kinase 1; C525690:PPP2R5A protein, human; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein