title: Characterization of spindle checkpoint kinase Mps1 reveals domain with functional and structural similarities to tetratricopeptide repeat motifs of Bub1 and BubR1 checkpoint kinases.
abstract: Kinetochore targeting of the mitotic kinases Bub1, BubR1, and Mps1 has been implicated in efficient execution of their functions in the spindle checkpoint, the self-monitoring system of the eukaryotic cell cycle that ensures chromosome segregation occurs with high fidelity. In all three kinases, kinetochore docking is mediated by the N-terminal region of the protein. Deletions within this region result in checkpoint failure and chromosome segregation defects. Here, we use an interdisciplinary approach that includes biophysical, biochemical, cell biological, and bioinformatics methods to study the N-terminal region of human Mps1. We report the identification of a tandem repeat of the tetratricopeptide repeat (TPR) motif in the N-terminal kinetochore binding region of Mps1, with close homology to the tandem TPR motif of Bub1 and BubR1. Phylogenetic analysis indicates that TPR Mps1 was acquired after the split between deutorostomes and protostomes, as it is distinguishable in chordates and echinoderms. Overexpression of TPR Mps1 resulted in decreased efficiency of both chromosome alignment and mitotic arrest, likely through displacement of endogenous Mps1 from the kinetochore and decreased Mps1 catalytic activity. Taken together, our multidisciplinary strategy provides new insights into the evolution, structural organization, and function of Mps1 N-terminal region.
authors.affiliation: Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom.
authors.forename: Semin
authors.initials: S
authors.lastname: Lee
authors.forename: Philippe
authors.initials: P
authors.lastname: Thebault
authors.forename: Luca
authors.initials: L
authors.lastname: Freschi
authors.forename: Sylvie
authors.initials: S
authors.lastname: Beaufils
authors.forename: Tom L
authors.initials: TL
authors.lastname: Blundell
authors.forename: Christian R
authors.initials: CR
authors.lastname: Landry
authors.forename: Victor M
authors.initials: VM
authors.lastname: Bolanos-Garcia
authors.forename: Sabine
authors.initials: S
authors.lastname: Elowe
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002417:Cattle; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002877:Chromosomes, Human / Q000235:genetics; D019295:Computational Biology; D004795:Enzyme Stability; D019143:Evolution, Molecular; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D059566:M Phase Cell Cycle Checkpoints; D051379:Mice; D008958:Models, Molecular; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011505:Protein-Tyrosine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D051381:Rats
chemical_list: C584278:Bub1b protein, mouse; D018797:Cell Cycle Proteins; D011505:Protein-Tyrosine Kinases; C584277:BUB1 protein, human; C584281:Bub1 protein, mouse; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases; C075840:TTK protein, human