Torque generation by one of the motor subunits of heterotrimeric kinesin-2.
Heterotrimeric kinesin-2 motors transport intraflagellar transport (IFT)-particles from the base to the tip of the axoneme to assemble and maintain cilia. These motors are distinct in containing two non-identical motor subunits together with an accessory subunit. We evaluated the significance of this organization by comparing purified wild type kinesin-2 holoenzymes that support IFT in vivo, with mutant trimers containing only one type of motor domain that do not support IFT in vivo. In motility assays, wild type kinesin-2 moved microtubules (MTs) at a rate intermediate between the rates supported by the two mutants. Interestingly, one of the mutants, but not the other mutant or the wild type protein, was observed to drive a persistent counter-clock-wise rotation of the gliding MTs. Thus one of the two motor domains of heterotrimeric kinesin-2 exerts torque as well as axial force as it moves along a MT, which may allow kinesin-2 to control its circumferential position around a MT doublet within the cilium.
Pan
Xiaoyu
X
Department of Molecular and Cell Biology, University of California at Davis, Davis, CA 95616, USA.
Acar
Seyda
S
Scholey
Jonathan M
JM
D054758:A Kinase Anchor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016547:Kinesins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D019415:Torque
D054758:A Kinase Anchor Proteins; C112944:A kinase anchor protein (kap-1), C elegans; D029742:Caenorhabditis elegans Proteins; C093002:OSM-3 protein, C elegans; C074152:kinesin-II; D016547:Kinesins