title: The Mitotic Checkpoint Complex Requires an Evolutionary Conserved Cassette to Bind and Inhibit Active APC/C.
abstract: The Spindle Assembly Checkpoint (SAC) ensures genomic stability by preventing sister chromatid separation until all chromosomes are attached to the spindle. It catalyzes the production of the Mitotic Checkpoint Complex (MCC), which inhibits Cdc20 to inactivate the Anaphase Promoting Complex/Cyclosome (APC/C). Here we show that two Cdc20-binding motifs in BubR1 of the recently identified ABBA motif class are crucial for the MCC to recognize active APC/C-Cdc20. Mutating these motifs eliminates MCC binding to the APC/C, thereby abolishing the SAC and preventing cells from arresting in response to microtubule poisons. These ABBA motifs flank a KEN box to form a cassette that is highly conserved through evolution, both in the arrangement and spacing of the ABBA-KEN-ABBA motifs, and association with the amino-terminal KEN box required to form the MCC. We propose that the ABBA-KEN-ABBA cassette holds the MCC onto the APC/C by binding the two Cdc20 molecules in the MCC-APC/C complex.
authors.affiliation: The Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge CB2 1QN, UK.
authors.forename: Barbara
authors.initials: B
authors.lastname: Di Fiore
authors.affiliation: The Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge CB2 1QN, UK.
authors.forename: Claudia
authors.initials: C
authors.lastname: Wurzenberger
authors.affiliation: Conway Institute of Biomolecular and Biomedical Sciences, University College Dublin, Dublin 4, Ireland.
authors.forename: Norman E
authors.initials: NE
authors.lastname: Davey
authors.affiliation: The Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge CB2 1QN, UK; Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK. Electronic address: jon.pines@icr.ac.uk.
authors.forename: Jonathon
authors.initials: J
authors.lastname: Pines
mesh_terms: D020816:Amino Acid Motifs; D064173:Anaphase-Promoting Complex-Cyclosome / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D005075:Biological Evolution; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism; D064199:Cdc20 Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002938:Ciona intestinalis / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D059566:M Phase Cell Cycle Checkpoints; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D059008:Time-Lapse Imaging
chemical_list: D064199:Cdc20 Proteins; C577488:CDC20 protein, human; D064173:Anaphase-Promoting Complex-Cyclosome; C584277:BUB1 protein, human; D017346:Protein Serine-Threonine Kinases
keywords: ABBA motif; Anaphase Promoting Complex; BubR1; Cdc20; Cyclosome; Spindle Assembly Checkpoint; checkpoint; mitosis