Role of Dynactin in the Intracellular Localization and Activation of Cytoplasmic Dynein

Abstract

Cytoplasmic dynein, the major minus end-directed motor protein in several cell types, transports a variety of intracellular cargo upon forming a processive tripartite complex with its activator dynactin and cargo adaptors such as Hook3 and BicD2. Our current understanding of dynein regulation stems from a combination of in vivo studies of cargo movement upon perturbation of dynein activity, in vitro single-molecule experiments, and cryo-electron microscopy studies of dynein structure and its interaction with dynactin and cargo adaptors. In this Perspective, we first consolidate data from recent publications to understand how perturbations to the dynein–dynactin interaction and dynactin’s in vivo localization alter the behavior of dynein-driven cargo transport in a cell type- and experimental condition-specific manner. In addition, we touch upon results from in vivo and in vitro studies to elucidate how dynein’s interaction with dynactin and cargo adaptors activates dynein and enhances its processivity. Finally, we propose questions that need to be addressed in the future with appropriate experimental designs so as to improve our understanding of the spatiotemporal regulation of dynein’s function in the context of the distribution and dynamics of dynactin in living cells.

Chlamydia trachomatis effector Dre1 interacts with dynactin to reposition host organelles during infection

“…Dynactin localizes at multiple sites in the cell, including MTs, the mitotic spindle, centrosome, nuclear envelope, GA, kinetochores, and the cell cortex (Tirumala & Ananthanarayanan, 2020). In HeLa cells infected with L2+pDre1 FLAG , endogenous p150 glued and Dre1 colocalize at the inclusion membrane (Figure S1D).…”

“…Dynactin localizes to multiple compartments and structures in cells where it organizes MTs, facilitates vesicle trafficking, and positions organelles, suggesting that there may be functionally distinct sub-populations of dynactin (Schroer & Verma, 2021;Tirumala & Ananthanarayanan, 2020). Since C. trachomatis inclusions associate with centrosomes and the MTOC (Grieshaber et al, 2003(Grieshaber et al, , 2006Hackstadt et al, 1999), we were particularly interested in the population of dynactin that localizes at the centrosome, where it anchors MTs and organizes MT arrays during interphase and mitosis (Askham et al, 2002;Quintyne et al, 1999;Quintyne & Schroer, 2002).…”

On and off controls within dynein–dynactin on native cargoes

“…How dynactin assists dynein is a long-standing controversy (2,5,6,12). Here we quantified the ability of native dynein-dynactin teams to generate force after perturbing the dynein-dynactin and dynactin-MT interactions on phagosomes and SLBs.…”

“…Additional interactions between dynein heavy chain and dynactin's Arp domain may stabilize the complex (3,4). How all these linkages help dynein-dynactin to function is hotly debated (5,6). Of particular interest is the recruitment of dynein-dynactin to cargoes by different adaptor proteins (1), as also revealed by the cryogenic electron microscopy (cryo-EM) structure of dynein-dynactinadaptor complexes wherein two dimeric dynein motors were found to be recruited as a pair (3,4).…”

Single-molecule imaging of cytoplasmic dyneinin celluloreveals the mechanism of motor activation and cargo movement

“…MT plus ends thus decorated with dynactin also accumulated dynein at these sites, and evidence suggested that cargo transport was initiated when these MT plus ends contacted intracellular cargo (Vaughan et al , 2002; Moughamian et al , 2013). However, MT plus end-mediated initiation of dynein-driven transport appears to vary with cell type and context (Watson & Stephens, 2006; Kim et al , 2007; Tirumala & Ananthanarayanan, 2020). Therefore, using SD microscopy in combination with super-resolution radial fluctuations (SRRF, (Gustafsson et al , 2016)) we first quantified the localisation of p150 (Fig.…”