title: Regulation of outer kinetochore Ndc80 complex-based microtubule attachments by the central kinetochore Mis12/MIND complex.
abstract: Multiple protein subcomplexes of the kinetochore cooperate as a cohesive molecular unit that forms load-bearing microtubule attachments that drive mitotic chromosome movements. There is intriguing evidence suggesting that central kinetochore components influence kinetochore-microtubule attachment, but the mechanism remains unclear. Here, we find that the conserved Mis12/MIND (Mtw1, Nsl1, Nnf1, Dsn1) and Ndc80 (Ndc80, Nuf2, Spc24, Spc25) complexes are connected by an extensive network of contacts, each essential for viability in cells, and collectively able to withstand substantial tensile load. Using a single-molecule approach, we demonstrate that an individual MIND complex enhances the microtubule-binding affinity of a single Ndc80 complex by fourfold. MIND itself does not bind microtubules. Instead, MIND binds Ndc80 complex far from the microtubule-binding domain and confers increased microtubule interaction of the complex. In addition, MIND activation is redundant with the effects of a mutation in Ndc80 that might alter its ability to adopt a folded conformation. Together, our results suggest a previously unidentified mechanism for regulating microtubule binding of an outer kinetochore component by a central kinetochore complex.
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195;
authors.forename: Emily M
authors.initials: EM
authors.lastname: Kudalkar
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195;
authors.forename: Emily A
authors.initials: EA
authors.lastname: Scarborough
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195;
authors.forename: Neil T
authors.initials: NT
authors.lastname: Umbreit
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195;
authors.forename: Alex
authors.initials: A
authors.lastname: Zelter
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195;
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Gestaut
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195;
authors.forename: Michael
authors.initials: M
authors.lastname: Riffle
authors.affiliation: Department of Genome Sciences, University of Washington, Seattle, WA 98195;
authors.forename: Richard S
authors.initials: RS
authors.lastname: Johnson
authors.affiliation: Department of Genome Sciences, University of Washington, Seattle, WA 98195;
authors.forename: Michael J
authors.initials: MJ
authors.lastname: MacCoss
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195.
authors.forename: Charles L
authors.initials: CL
authors.lastname: Asbury
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195; tdavis@uw.edu.
authors.forename: Trisha N
authors.initials: TN
authors.lastname: Davis
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D018386:Kinetochores / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D017434:Protein Structure, Tertiary
chemical_list: D029742:Caenorhabditis elegans Proteins; D008869:Microtubule-Associated Proteins; D046912:Multiprotein Complexes; C492665:NDC-80 protein, C elegans
keywords: MIND/Mis12 complex; Ndc80 complex; kinetochore; microtubules; mitosis