title: Mechanism of transport of IFT particles in C. elegans cilia by the concerted action of kinesin-II and OSM-3 motors.
abstract: The assembly and function of cilia on Caenorhabditis elegans neurons depends on the action of two kinesin-2 motors, heterotrimeric kinesin-II and homodimeric OSM-3-kinesin, which cooperate to move the same intraflagellar transport (IFT) particles along microtubule (MT) doublets. Using competitive in vitro MT gliding assays, we show that purified kinesin-II and OSM-3 cooperate to generate movement similar to that seen along the cilium in the absence of any additional regulatory factors. Quantitative modeling suggests that this could reflect an alternating action mechanism, in which the motors take turns to move along MTs, or a mechanical competition, in which the motors function in a concerted fashion to move along MTs with the slow motor exerting drag on the fast motor and vice versa. In vivo transport assays performed in Bardet-Biedl syndrome (BBS) protein and IFT motor mutants favor a mechanical competition model for motor coordination in which the IFT motors exert a BBS protein-dependent tension on IFT particles, which controls the IFT pathway that builds the cilium foundation.
authors.affiliation: Section of Molecular and Cellular Biology, Center for Genetics and Development, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Pan
authors.forename: Guangshuo
authors.initials: G
authors.lastname: Ou
authors.forename: Gul
authors.initials: G
authors.lastname: Civelekoglu-Scholey
authors.forename: Oliver E
authors.initials: OE
authors.lastname: Blacque
authors.forename: Nicholas F
authors.initials: NF
authors.lastname: Endres
authors.forename: Li
authors.initials: L
authors.lastname: Tao
authors.forename: Alex
authors.initials: A
authors.lastname: Mogilner
authors.forename: Michel R
authors.initials: MR
authors.lastname: Leroux
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Vale
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Scholey
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001692:Biological Transport; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002923:Cilia / Q000378:metabolism / Q000502:physiology*; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012617:Sea Urchins
chemical_list: D029742:Caenorhabditis elegans Proteins; D020409:Molecular Motor Proteins; C093002:OSM-3 protein, C elegans; D011994:Recombinant Proteins; C074152:kinesin-II; D016547:Kinesins