title: Torque generation of kinesin motors is governed by the stability of the neck domain.
abstract: In long-range transport of cargo, prototypical kinesin-1 steps along a single protofilament on the microtubule, an astonishing behavior given the number of theoretically available binding sites on adjacent protofilaments. Using a laser trap assay, we analyzed the trajectories of several representatives from the kinesin-2 class on freely suspended microtubules. In stark contrast to kinesin-1, these motors display a wide range of left-handed spiraling around microtubules and thus generate torque during cargo transport. We provide direct evidence that kinesin's neck region determines the torque-generating properties. A model system based on kinesin-1 corroborates this result: disrupting the stability of the neck by inserting flexible peptide stretches resulted in pronounced left-handed spiraling. Mimicking neck stability by crosslinking significantly reduced the spiraling of the motor up to the point of protofilament tracking. Finally, we present a model that explains the physical basis of kinesin's spiraling around the microtubule.
authors.affiliation: Physik Department E22, Technische Universität München, James-Franck-Strasse, 85748 Garching, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Brunnbauer
authors.forename: Renate
authors.initials: R
authors.lastname: Dombi
authors.forename: Thi-Hieu
authors.initials: TH
authors.lastname: Ho
authors.forename: Manfred
authors.initials: M
authors.lastname: Schliwa
authors.forename: Matthias
authors.initials: M
authors.lastname: Rief
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Ökten
mesh_terms: D000595:Amino Acid Sequence; D001692:Biological Transport; D016547:Kinesins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D019415:Torque
chemical_list: D016547:Kinesins