title: The internal Cdc20 binding site in BubR1 facilitates both spindle assembly checkpoint signalling and silencing.
abstract: Improperly attached kinetochores activate the spindle assembly checkpoint (SAC) and by an unknown mechanism catalyse the binding of two checkpoint proteins, Mad2 and BubR1, to Cdc20 forming the mitotic checkpoint complex (MCC). Here, to address the functional role of Cdc20 kinetochore localization in the SAC, we delineate the molecular details of its interaction with kinetochores. We find that BubR1 recruits the bulk of Cdc20 to kinetochores through its internal Cdc20 binding domain (IC20BD). We show that preventing Cdc20 kinetochore localization by removal of the IC20BD has a limited effect on the SAC because the IC20BD is also required for efficient SAC silencing. Indeed, the IC20BD can disrupt the MCC providing a mechanism for its role in SAC silencing. We thus uncover an unexpected dual function of the second Cdc20 binding site in BubR1 in promoting both efficient SAC signalling and SAC silencing.
authors.affiliation: The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, Copenhagen 2200, Denmark.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Lischetti
authors.affiliation: The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, Copenhagen 2200, Denmark.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, Copenhagen 2200, Denmark.
authors.forename: Garry G
authors.initials: GG
authors.lastname: Sedgwick
authors.affiliation: Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford OX3 0BP, UK.
authors.forename: Victor M
authors.initials: VM
authors.lastname: Bolanos-Garcia
authors.affiliation: The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, Copenhagen 2200, Denmark.
authors.forename: Jakob
authors.initials: J
authors.lastname: Nilsson
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002384:Catalysis; D064199:Cdc20 Proteins / Q000737:chemistry*; D020868:Gene Silencing; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores / Q000378:metabolism; D064246:Mad2 Proteins / Q000378:metabolism; D008870:Microtubules / Q000737:chemistry; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry*; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D008941:Spindle Apparatus
chemical_list: D064199:Cdc20 Proteins; C577697:MAD2L1 protein, human; D064246:Mad2 Proteins; C577488:CDC20 protein, human; C584277:BUB1 protein, human; D017346:Protein Serine-Threonine Kinases