title: The mitotic kinesin-14 KlpA contains a context-dependent directionality switch.
abstract: Kinesin-14s are commonly known as nonprocessive minus end-directed microtubule motors that function mainly for mitotic spindle assembly. Here we show using total internal reflection fluorescence microscopy that KlpA-a kinesin-14 from Aspergillus nidulans-is a context-dependent bidirectional motor. KlpA exhibits plus end-directed processive motility on single microtubules, but reverts to canonical minus end-directed motility when anchored on the surface in microtubule-gliding experiments or interacting with a pair of microtubules in microtubule-sliding experiments. Plus end-directed processive motility of KlpA on single microtubules depends on its N-terminal nonmotor microtubule-binding tail, as KlpA without the tail is nonprocessive and minus end-directed. We suggest that the tail is a de facto directionality switch for KlpA motility: when the tail binds to the same microtubule as the motor domain, KlpA is a plus end-directed processive motor; in contrast, when the tail detaches from the microtubule to which the motor domain binds, KlpA becomes minus end-directed.
authors.affiliation: Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Popchock
authors.affiliation: Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA.
authors.forename: Kuo-Fu
authors.initials: KF
authors.lastname: Tseng
authors.affiliation: Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA.|School of Physics and Electronics, Henan University, Kaifeng, Henan 475004, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA.
authors.forename: P Andrew
authors.initials: PA
authors.lastname: Karplus
authors.affiliation: Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Xiang
authors.affiliation: Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA.|Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA.
authors.forename: Weihong
authors.initials: W
authors.lastname: Qiu
mesh_terms: D001233:Aspergillus nidulans / Q000502:physiology*; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D016547:Kinesins / Q000737:chemistry / Q000378:metabolism*; D008856:Microscopy, Fluorescence / Q000379:methods; D008870:Microtubules / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D000072760:Single Molecule Imaging / Q000379:methods; D008941:Spindle Apparatus / Q000378:metabolism*; D059008:Time-Lapse Imaging / Q000379:methods
chemical_list: D005656:Fungal Proteins; C444432:KLPA protein, Aspergillus nidulans; D011994:Recombinant Proteins; D016547:Kinesins