title: Dynactin functions as both a dynamic tether and brake during dynein-driven motility.
abstract: Dynactin is an essential cofactor for most cellular functions of the microtubule motor cytoplasmic dynein, but the mechanism by which dynactin activates dynein remains unclear. Here we use single molecule approaches to investigate dynein regulation by the dynactin subunit p150(Glued). We investigate the formation and motility of a dynein-p150(Glued) co-complex using dual-colour total internal reflection fluorescence microscopy. p150(Glued) recruits and tethers dynein to the microtubule in a concentration-dependent manner. Single molecule imaging of motility in cell extracts demonstrates that the CAP-Gly domain of p150(Glued) decreases the detachment rate of the dynein-dynactin complex from the microtubule and also acts as a brake to slow the dynein motor. Consistent with this important role, two neurodegenerative disease-causing mutations in the CAP-Gly domain abrogate these functions in our assays. Together, these observations support a model in which dynactin enhances the initial recruitment of dynein onto microtubules and promotes the sustained engagement of dynein with its cytoskeletal track.
authors.affiliation: 1] Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA [2] Department of Biology Graduate Group, School of Arts and Sciences at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA.
authors.forename: Swathi
authors.initials: S
authors.lastname: Ayloo
authors.affiliation: Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA.
authors.forename: Jacob E
authors.initials: JE
authors.lastname: Lazarus
authors.affiliation: Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01008, USA.
authors.forename: Aditya
authors.initials: A
authors.lastname: Dodda
authors.affiliation: Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA.
authors.forename: Mariko
authors.initials: M
authors.lastname: Tokito
authors.affiliation: Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA.
authors.forename: E Michael
authors.initials: EM
authors.lastname: Ostap
authors.affiliation: Department of Physiology and the Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA.
authors.forename: Erika L F
authors.initials: EL
authors.lastname: Holzbaur
mesh_terms: D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002465:Cell Movement / Q000502:physiology; D002522:Chlorocebus aethiops; D000072159:Dynactin Complex; D004398:Dyneins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: C000606360:DCTN1 protein, human; C000606364:Dctn1 protein, mouse; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D004398:Dyneins