The long-term goal of this research project is to understand how the microtubule (MT)-based motor cytoplasmic dynein ("dynein") is regulated. Dynein is the largest and most complex of all cytoskeletal motors; this >1 MDa dimeric complex contains numerous mechanical elements whose movements must be coordinated over strikingly long molecular distances to achieve processive motility along MTs. In addition to its enormous size, dynein is also the most versatile of the molecular motors;in sharp contrast to the 45 kinesins and 39 myosins present in humans, a single dynein gene product is responsible for transporting macromolecules within neurons, constructing the mitotic spindle, polarizing cells, and anchoring mRNAs during development. To give dynein the functional plasticity necessary for carrying out its many roles, several ubiquitous co-factors interact with dynein, including Lis1 and the dynactin complex. This project will apply our combined expertise in biochemistry, single-molecule biophysics and cryo-electron microscopy to address the structural and mechanistic bases of dynein's interaction with MTs and its regulation by Lis1 and dynactin. We recently showed that binding of dynein to MTs is accompanied by conformational changes in its MT- binding domain and that Lis1 acts as a "clutch" to uncouple MT binding and release from ATP hydrolysis, promoting a strongly MT-attached state. Dynactin, a 1.2 MDa complex, enhances dynein's processivity and is required for nearly all dynein functions in cells, but its mechanism of action is poorly understood. This grant will address major mechanistic questions about dynein and its regulation. What are the structural and mechanistic bases of MT binding (Aim 1), and of regulation by Lis1 (Aim 2) and dynactin (Aim 3)?

Public Health Relevance

Dynein is a large and complex molecular motor that transports a wide variety of cellular cargos. This is crucial in neurons where defects in dynein-mediated transport lead to neurodevelopmental and neurodegenerative diseases. This research will provide insight into these diseases at a molecular level by investigating how dynein's multiple mechanical elements are coordinated to allow movement, and how this coordination is regulated by other proteins to give dynein the functional plasticity it needs to carry out its many cellular roles.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM107214-01A1
Application #
8630495
Study Section
Macromolecular Structure and Function C Study Section (MSFC)
Program Officer
Gindhart, Joseph G
Project Start
2014-06-10
Project End
2018-02-28
Budget Start
2014-06-10
Budget End
2015-02-28
Support Year
1
Fiscal Year
2014
Total Cost
$486,581
Indirect Cost
$196,498
Name
Harvard University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
02115
Cianfrocco, Michael A; Leschziner, Andres E (2014) Traffic control: adaptor proteins guide dynein-cargo takeoff. EMBO J 33:1845-6