title: Dynactin is required for bidirectional organelle transport.
abstract: Kinesin II is a heterotrimeric plus end-directed microtubule motor responsible for the anterograde movement of organelles in various cell types. Despite substantial literature concerning the types of organelles that kinesin II transports, the question of how this motor associates with cargo organelles remains unanswered. To address this question, we have used Xenopus laevis melanophores as a model system. Through analysis of kinesin II-mediated melanosome motility, we have determined that the dynactin complex, known as an anchor for cytoplasmic dynein, also links kinesin II to organelles. Biochemical data demonstrates that the putative cargo-binding subunit of Xenopus kinesin II, Xenopus kinesin II-associated protein (XKAP), binds directly to the p150Glued subunit of dynactin. This interaction occurs through aa 530-793 of XKAP and aa 600-811 of p150Glued. These results reveal that dynactin is required for transport activity of microtubule motors of opposite polarity, cytoplasmic dynein and kinesin II, and may provide a new mechanism to coordinate their activities.
authors.affiliation: Department of Cell and Structural Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801.
authors.forename: Sean W
authors.initials: SW
authors.lastname: Deacon
authors.forename: Anna S
authors.initials: AS
authors.lastname: Serpinskaya
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Vaughan
authors.forename: Monica
authors.initials: M
authors.lastname: Lopez Fanarraga
authors.forename: Isabelle
authors.initials: I
authors.lastname: Vernos
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Vaughan
authors.forename: Vladimir I
authors.initials: VI
authors.lastname: Gelfand
mesh_terms: D000818:Animals; D001667:Binding, Competitive / Q000502:physiology; D029742:Caenorhabditis elegans Proteins; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D000072159:Dynactin Complex; D016547:Kinesins / Q000378:metabolism; D046911:Macromolecular Substances; D008547:Melanophores / Q000378:metabolism*; D020460:Melanosomes / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008954:Models, Biological; D009124:Muscle Proteins / Q000378:metabolism*; D015388:Organelles / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D021381:Protein Transport / Q000502:physiology*; D029867:Xenopus Proteins; D014982:Xenopus laevis
chemical_list: D029742:Caenorhabditis elegans Proteins; D002135:Calcium-Binding Proteins; D000072159:Dynactin Complex; D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins; D009124:Muscle Proteins; C093002:OSM-3 protein, C elegans; C499376:XKLP3 protein, Xenopus; D029867:Xenopus Proteins; C074152:kinesin-II; D016547:Kinesins