title: Kinesin-12 Kif15 targets kinetochore fibers through an intrinsic two-step mechanism.
abstract: Proteins that recognize and act on specific subsets of microtubules (MTs) enable the varied functions of the MT cytoskeleton. We recently discovered that Kif15 localizes exclusively to kinetochore fibers (K-fibers) or bundles of kinetochore-MTs within the mitotic spindle. It is currently speculated that the MT-associated protein TPX2 loads Kif15 onto spindle MTs, but this model has not been rigorously tested. Here, we show that Kif15 accumulates on MT bundles as a consequence of two inherent biochemical properties. First, Kif15 is self-repressed by its C terminus. Second, Kif15 harbors a nonmotor MT-binding site, enabling dimeric Kif15 to crosslink and slide MTs. Two-MT binding activates Kif15, resulting in its accumulation on and motility within MT bundles but not on individual MTs. We propose that Kif15 targets K-fibers via an intrinsic two-step mechanism involving molecular unfolding and two-MT binding. This work challenges the current model of Kif15 regulation and provides the first account of a kinesin that specifically recognizes a higher-order MT array.
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Emma G
authors.initials: EG
authors.lastname: Sturgill
authors.affiliation: Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA.
authors.forename: Dibyendu Kumar
authors.initials: DK
authors.lastname: Das
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Takizawa
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Yongdae
authors.initials: Y
authors.lastname: Shin
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Collier
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Ohi
authors.affiliation: Department of Biomedical Engineering, Texas A&M, College Station, TX 77843, USA; School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-722, Korea.
authors.forename: Wonmuk
authors.initials: W
authors.lastname: Hwang
authors.affiliation: Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Lang
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA. Electronic address: ryoma.ohi@vanderbilt.edu.
authors.forename: Ryoma
authors.initials: R
authors.lastname: Ohi
mesh_terms: D002453:Cell Cycle; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D016547:Kinesins / Q000235:genetics* / Q000378:metabolism; D018386:Kinetochores / Q000378:metabolism* / Q000648:ultrastructure; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D008938:Mitosis; D008941:Spindle Apparatus / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: C486567:KIF15 protein, human; D016547:Kinesins