title: Embedding dual function into molecular motors through collective motion.
abstract: Protein motors, such as kinesins and dyneins, bind to a microtubule and travel along it in a specific direction. Previously, it was thought that the directionality for a given motor was constant in the absence of an external force. However, the directionality of the kinesin-5 Cin8 was recently found to change as the number of motors that bind to the same microtubule is increased. Here, we introduce a simple mechanical model of a microtubule-sliding assay in which multiple motors interact with the filament. We show that, due to the collective phenomenon, the directionality of the motor changes (e.g., from minus- to plus- end directionality), depending on the number of motors. This is induced by a large diffusive component in the directional walk and by the subsequent frustrated motor configuration, in which multiple motors pull the filament in opposite directions, similar to a game of tug-of-war. A possible role of the dual-directional motors for the mitotic spindle formation is also discussed. Our framework provides a general mechanism to embed two conflicting tasks into a single molecular machine, which works context-dependently.
authors.affiliation: Universal Biology Institute, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Nen
authors.initials: N
authors.lastname: Saito
authors.affiliation: Universal Biology Institute, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.|Research Center for Complex Systems Biology, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Kaneko
mesh_terms: D000465:Algorithms; D000818:Animals; D004398:Dyneins / Q000378:metabolism; D006801:Humans; D016547:Kinesins / Q000378:metabolism; D055595:Mechanical Phenomena; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D009038:Motion; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
chemical_list: D020409:Molecular Motor Proteins; D029701:Saccharomyces cerevisiae Proteins; D004398:Dyneins; D016547:Kinesins