Dynactin Functions as Both a Dynamic Tether and Brake during Dynein-Driven Motility

Ayloo, Swathi; Lazarus, Jacob E.; Dodda, Aditya G.; Tokito, Mariko; Ostap, E. Michael; Holzbaur, Erika L.F.

doi:10.1016/j.bpj.2014.11.748

Cited by 8 publications

(18 citation statements)

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“…For example, what configuration does dynactin take in the cell and could CC1 adopt an extended conformation when dynactin binds with MTs or dynein, like postulated in Cianfrocco et al (2015) or Carter et al (2016)? Furthermore, the results of in vitro assays which examined the effect of CC1 on dynein motility are conflicting (Ayloo et al, 2014;Culver-Hanlon et al, 2006;Kobayashi et al, 2017;Tripathy et al, 2014), implying there exists some regulatory mechanism within CC1. Thus, determining the location and conformation of CC1 in the dynactin complex, which is not averaged and not docked, is central in our pursuit of dynactin in action.…”

Section: Introductionmentioning

confidence: 99%

Domain organization and conformational change of dynactin p150

Saito

Murayama

Hata

et al. 2018

Preprint

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Dynactin is a principal regulator of the minus-end directed microtubule motor dynein. The sidearm of dynactin is essential for binding to microtubules and regulation of dynein activity. Although our understanding of the structure of the dynactin backbone (Arp1 rod) has greatly improved recently, structural details of the sidearm part remain elusive. Here, electron microscopy of individual molecules of the dynactin complex revealed that the sidearm was highly flexible and exhibited diverse morphologies.Utilizing mutants for nanogold labeling and deletion analysis, we determined the domain organization of the largest subunit p150 and identified a filamentous structure protruding from the head domain of the sidearm as the coiled-coil 1 (CC1), the dynein-binding domain, in p150. Furthermore, the protrusion formed by CC1 exhibited either a folded or an extended form, suggesting that CC1 works as an extending "arm". These findings provide clues to understand how dynactin binds to microtubules and regulates dynein.

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Section: Introductionmentioning

confidence: 99%

Domain organization and conformational change of dynactin p150

Saito

Murayama

Hata

et al. 2018

Preprint

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“…Recent structural studies suggest that the docking of dynein's tail domain into dynactin's actin-related 1 (Arp1) filament may reorient the dynein motor domains for productive motility (Urnavicius et al, 2015). Additionally, dynactin contains its own microtubule binding domain, located at the N-terminus of the p150 Glued subunit (hereafter termed p150) (Schroer, 2004), but the role of this domain in dynein motility remains unclear (Ayloo et al, 2014;Culver-Hanlon et al, 2006;Dixit et al, 2008;Kardon et al, 2009;Kim et al, 2007;Tripathy et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Tyrosination of α-Tubulin Controls The Initiation of Processive Dynein-Dynactin Motility

McKenney

Huynh

Vale

et al. 2015

Preprint

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Post-translational modifications (PTMs) of α/β−tubulin are believed to regulate interactions with microtubule binding proteins. A well-characterized PTM involves the removal and re-ligation of the C-terminal tyrosine on α-tubulin, but the purpose of this tyrosination-detyrosination cycle remains elusive. Here, we examined the processive motility of mammalian dynein complexed with dynactin and BicD2 (DDB) on tyrosinated versus detyrosinated microtubules. Motility was decreased ~4-fold on detyrosinated microtubules, constituting the largest effect of a tubulin PTM on motor function observed to date. This preference is mediated by dynactin's microtubule binding p150 subunit rather than dynein itself. Interestingly, on chimeric microtubules, DDB molecules that initiated movement on tyrosinated tubulin continued moving into a region of detyrosinated tubulin. This result indicates that the α-tubulin tyrosine facilitates initial motor-tubulin encounters, but is not needed for subsequent motility. Our results reveal a strong effect of the C-terminal α-tubulin tyrosine on dynein-dynactin motility and suggest that the tubulin tyrosination cycle could modulate the initiation of dynein-driven motility in cells.

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“…Hook Proteins Induce Highly Processive Runs with Enhanced Velocities-To characterize the functional effects of Hook adaptors on dynein, we utilized an in vitro single-molecule approach using total internal reflection fluorescence (TIRF) microscopy of cell extracts to characterize dynein-dynactin motility (10). We expressed Halo-tagged Hook constructs in HeLa cells and labeled cells with TMR-labeled HaloTag ligand prior to generation of cell lysates.…”

Section: The N-terminal Domain Of Hook Proteins Does Not Bind Microtumentioning

confidence: 99%

“…The first major regulator to be identified was dynactin, a large multisubunit protein complex required for most functions of dynein within the cell. Dynactin forms a co-complex with dynein (5-8) that enhances the initial recruitment of dynein to the microtubule (9,10) and mediates the association of dynein with some intracellular cargos (11)(12)(13)(14). A second major dynein regulator, Lis1, binds to the dynein motor domain and blocks the required linker swing in the mechanochemical cycle for dynein; thus, Lis1 binding induces a non-motile state of dynein that binds tightly to the microtubule (15).…”

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confidence: 99%

Hook Adaptors Induce Unidirectional Processive Motility by Enhancing the Dynein-Dynactin Interaction

Olenick

Tokito²,

Boczkowska³

et al. 2016

Journal of Biological Chemistry

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Cytoplasmic dynein drives the majority of minus end-directed vesicular and organelle motility in the cell. However, it remains unclear how dynein is spatially and temporally regulated given the variety of cargo that must be properly localized to maintain cellular function. Recent work has suggested that adaptor proteins provide a mechanism for cargo-specific regulation of motors. Of particular interest, studies in fungal systems have implicated Hook proteins in the regulation of microtubule motors. Here we investigate the role of mammalian Hook proteins, Hook1 and Hook3, as potential motor adaptors. We used optogenetic approaches to specifically recruit Hook proteins to organelles and observed rapid transport of peroxisomes to the perinuclear region of the cell. This rapid and efficient translocation of peroxisomes to microtubule minus ends indicates that mammalian Hook proteins activate dynein rather than kinesin motors. Biochemical studies indicate that Hook proteins interact with both dynein and dynactin, stabilizing the formation of a supramolecular complex. Complex formation requires the N-terminal domain of Hook proteins, which resembles the calponin-homology domain of end-binding (EB) proteins but cannot bind directly to microtubules. Single-molecule motility assays using total internal reflection fluorescence microscopy indicate that both Hook1 and Hook3 effectively activate cytoplasmic dynein, inducing longer run lengths and higher velocities than the previously characterized dynein activator bicaudal D2 (BICD2). Together, these results suggest that dynein adaptors can differentially regulate dynein to allow for organellespecific tuning of the motor for precise intracellular trafficking.Microtubules provide a polarized highway to facilitate the transport of organelles and vesicles throughout the cell. The minus ends of microtubules are usually nucleated near the cell center, with the plus ends oriented outward, toward the cell periphery. This polarity ensures that microtubule motors drive motility in a specific direction; kinesin motors generally drive plus end motility, whereas minus end traffic is primarily driven by cytoplasmic dynein. Regulation of these opposing motors is vital for cell survival, particularly in specialized cells like neurons that require efficient transport over long distances (1). However, it remains unclear how microtubule motors are spatially and temporally regulated to control the intracellular trafficking of specific cargo. As a single major form of cytoplasmic dynein drives the transport of a wide array of cargos, including endosomes, RNA granules, and mitochondria (2-4), it is likely that the transport properties of dynein are modulated by the binding of cargo-specific adaptor molecules.

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Dynactin Functions as Both a Dynamic Tether and Brake during Dynein-Driven Motility

Cited by 8 publications

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Domain organization and conformational change of dynactin p150

Domain organization and conformational change of dynactin p150

Tyrosination of α-Tubulin Controls The Initiation of Processive Dynein-Dynactin Motility

Hook Adaptors Induce Unidirectional Processive Motility by Enhancing the Dynein-Dynactin Interaction

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