Dynein

Cytoplasmic dynein uses the energy from ATP hydrolysis to step along microtubule tracks in eukaryotic cells. It is one of the most versatile molecular motors known, with critical roles in powering transport of diverse cargos, constructing the cell division machinery, and polarizing molecules during development. Remarkably, there is just one cytoplasmic dynein responsible for all of its diverse cellular tasks. It therefore relies on interactions with regulating proteins to achieve specificity of function but little is known about these co-factors and how regulation is achieved. Recent data from our collaborator’s group (Reck-Peterson lab) and others show that dynein’s motile behavior is altered by Lis1, a ubiquitous dynein co-factor associated with a severe brain development disorder in humans (lissencephaly). Using a combination of cryo-EM, molecular modeling, biochemistry and single-molecule assays, our aim is to understand at the structural, mechanistic level how Lis1 regulates dynein motility and ultimately how a single dynein can achieve the versatility of function seen in vivo.

One of the longest-standing questions in the molecular motors field is how dynein coordinates its multiple parts to achieve such movement. The basic motor is a homodimer of ~500 KDa chains. Within each chain, the head, a ring-shaped AAA+ motor domain, coordinates its activity with cycles of microtubule binding and release driven by the microtubule binding domain (MTBD) located 25 nm away. We have recently showed how dynein’s MTBD recognizes the microtubule interface and have proposed a model for how it communicates MT-binding to the motor. We also revealed that single point mutations in the MTBD exhibited an approximately six-fold increase in dynein’s run length. The appearance of enhanced processivity in dynein raises many questions. Why has dynein evolved to be sub-maximally processive? Is processivity a property that has been tuned among dynein families according to their biological function? Elucidation of the structural basis for processivity will require visualizing how dynein’s mechanical elements are arranged as the motor walks along MTs. These studies may yield insights into the biology of a wide range of processes such as intracellular transport and cell division.

Publications

* Equal contribution
# Co-corresponding authors

DeSantis ME*, Cianfrocco MA*, Htet ZM*, Tran PT, Reck-Peterson SL# and Leschziner AE# (2017). Lis1 has two opposing modes of regulating cytoplasmic dynein. Cell 170:1197-1201

Cianfrocco MA*, DeSantis ME*, Leschziner AE and Reck-Peterson SL (2015). Mechanism and regulation of cytoplasmic dynein. Annu. Rev. Cell. Dev. Biol. 31:83-108

Toropova K*, Zou S*, Roberts AJ, Redwine WB, Goodman BS, Reck-Peterson SL#, Leschziner AE# (2014). Lis1 regulates dynein by sterically blocking its mechanochemical cycle. eLIFE: 03372 (link)

Cianfrocco MA, Leschziner AE (2014).Traffic control: adaptor proteins guide dynein-cargo takeoff. EMBO J 33:1845-6 [News & Views]

Derr ND*, Goodman BS*, Jungmann R, Leschziner AE, Shih WM, Reck-Peterson SL (2012). Tug-of-war in motor protein ensembles revealed with a programmable DNA origami scaffold. Science [Epub ahead of print.]{download PDF}

Redwine WB*, Hernandez-Lopez R*, Zou S, Huang J, Reck-Peterson SL, Leschziner AE (2012). Structural basis for microtubule binding and release by dynein. Science, 337:1532-1536 {download PDF}{Supplemental movies}

Huang J*, Roberts A*, Leschziner AE, Reck-Peterson SL (2012). Lis1 acts as a "clutch" between the ATPase and microtubule-binding domains of the dynein motor. Cell, 150:975-986 {download PDF}

 
 Lis1 uncouples ATP hydrolysis and MT release in dynein but the structural mechanisms remain unclear.

Lis1 uncouples ATP hydrolysis and MT release in dynein but the structural mechanisms remain unclear.