title: Processive bidirectional motion of dynein-dynactin complexes in vitro.
abstract: Cytoplasmic dynein is the primary molecular motor responsible for transport of vesicles, organelles, proteins and RNA cargoes from the periphery of the cell towards the nucleus along the microtubule cytoskeleton of eukaryotic cells. Dynactin, a large multi-subunit activator of dynein, docks cargo to the motor and may enhance dynein processivity. Here, we show that individual fluorescently labelled dynein-dynactin complexes exhibit bidirectional and processive motility towards both the plus and minus ends of microtubules. The dependence of this activity on substrate ATP concentration, nucleotide analogues and inhibitors suggests that bidirectional motility is an active energy-transduction property of dynein-dynactin motor mechano-chemistry. The unique motility characteristics observed may reflect the flexibility of the dynein structure that leads to an enhanced ability to navigate around obstacles in the cell.
authors.affiliation: Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Ross
authors.forename: Karen
authors.initials: K
authors.lastname: Wallace
authors.forename: Henry
authors.initials: H
authors.lastname: Shuman
authors.forename: Yale E
authors.initials: YE
authors.lastname: Goldman
authors.forename: Erika L F
authors.initials: EL
authors.lastname: Holzbaur
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism*; D005456:Fluorescent Dyes; D040542:Mechanotransduction, Cellular; D051379:Mice; D008822:Mice, Transgenic; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D020409:Molecular Motor Proteins; D009038:Motion; D011485:Protein Binding
chemical_list: D000072159:Dynactin Complex; D005456:Fluorescent Dyes; D008869:Microtubule-Associated Proteins; D020409:Molecular Motor Proteins; D000255:Adenosine Triphosphate; D004398:Dyneins