title: Rab6a releases LIS1 from a dynein idling complex and activates dynein for retrograde movement.
abstract: Cytoplasmic dynein drives the movement of a wide range of cargoes towards the minus ends of microtubules. We previously demonstrated that LIS1 forms an idling complex with dynein, which is transported to the plus ends of microtubules by kinesin motors. Here we report that the small GTPase Rab6a is essential for activation of idling dynein. Immunoprecipitation and microtubule pull-down assays reveal that the GTP bound mutant, Rab6a(Q72L), dissociates LIS1 from a LIS1-dynein complex, activating dynein movement in in vitro microtubule gliding assays. We monitor transient interaction between Rab6a(Q72L) and dynein in vivo using dual-colour fluorescence cross-correlation spectroscopy in dorsal root ganglion (DRG) neurons. Finally, we demonstrate that Rab6a(Q72L) mediates LIS1 release from a LIS1-dynein complex followed by dynein activation through an in vitro single-molecule assay using triple-colour quantum dots. Our findings reveal a surprising function for GTP bound Rab6a as an activator of idling dynein.
authors.affiliation: Department of Genetic Disease Research, Osaka City University, Graduate School of Medicine, Asahi-machi 1-4-3, Abeno, Osaka, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Yamada
authors.forename: Kanako
authors.initials: K
authors.lastname: Kumamoto
authors.forename: Shintaro
authors.initials: S
authors.lastname: Mikuni
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Arai
authors.forename: Masataka
authors.initials: M
authors.lastname: Kinjo
authors.forename: Takeharu
authors.initials: T
authors.lastname: Nagai
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tsukasaki
authors.forename: Tomonobu M
authors.initials: TM
authors.lastname: Watanabe
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Fukui
authors.forename: Mingyue
authors.initials: M
authors.lastname: Jin
authors.forename: Shiori
authors.initials: S
authors.lastname: Toba
authors.forename: Shinji
authors.initials: S
authors.lastname: Hirotsune
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000378:metabolism*; D000818:Animals; D015536:Down-Regulation; D004398:Dyneins / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006160:Guanosine Triphosphate / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D050505:Mutant Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D034741:RNA, Small Interfering / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; D050505:Mutant Proteins; D034741:RNA, Small Interfering; C094135:Rab6 protein; D006160:Guanosine Triphosphate; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; C513190:Pafah1b1 protein, mouse; D004398:Dyneins; D020691:rab GTP-Binding Proteins