Molecular Motors

Dynein

Cytoplasmic dynein is a multi-protein motor complex responsible for all minus-end directed microtubule transport in most eukaryotic cells.  Dynein carries out a large number of functions in the cell and is subject to complicated regulatory control by accessory factors (Kardon and Vale, 2009).  In relation to the other microtubule motor family, the kinesins, dynein is much larger and complicated.  Despite being identified 20 years earlier than kinesin, dynein’s complexity has made it relatively intractable to studies of its mechanism of movement.  Dynein also belongs to the AAA family of ATPases and thus is evolutionarily unrelated to kinesin (which is related to myosin and G proteins; see the web section on kinesins).  Katanin/spastin, microtubule severing proteins studied by our lab, are also members of the AAA ATPase family.

Our lab studied dynein in the late 1980s and early 1990s, primarily focusing on developing in vitro motility assays for ciliary dyneins.  Some of the results that emerged from that period including the finding that certain dyneins can produce a torque on microtubules that produced rotation as well as forward translocation (Vale and Toyoshima, 1988), that dynein can undergo one-dimensional diffusion along microtubules (Vale et al., 1989), which was later found for certain kinesins as well by Hirokawa and colleagues, and that dynein and kinesin can compete in an unsual way to produce directionality instability of microtubule movement rather than a conventional tug-of-war that grinds movement to a halt (Vale et al.,1992).

We then stopped working on dyneins in favor of kinesin, which was ripe for study in the 1990s using protein engineering by bacterial expression along with structural and single molecule techniques.  However, as the kinesin mechanism became better and better understood, we have focused our primary attention on the dynein motility mechanism since the mid-2000s.  Our lab uses a variety of approaches to study dynein’s motor function including protein engineering (Reck-Peterson et al., 2006), single molecule biophysics (Reck-Peterson et al., 2006; Gennerich et al., 2007, Cho et al., 2008; Carter et al. 2010), and x-ray crystallography (Carter et al., 2010; Carter et al., 2011).  The lab has established S. cerevisiae as a genetically tractable recombinant expression system for the production of engineered dynein proteins (Reck-Peterson et al., 2004 and 2006). Using this system the lab showed that cytoplasmic dynein is a processive motor that moves along a microtubule taking variable step sizes (Reck-Peterson et al., 2006). In addition to generating forces in the presence of ATP and switching to non-processive modes in a load dependent manner, we also found that dynein can be driven to move processively along a microtubule (either in the backward or forward direction) by load in the absence of nucleotide (Gennerich et al., 2007).  We have also used this system to dissect the roles of dynein's various ATPase domains (Reck-Peterson et al., 2004 ; Cho et al., 2008), and how dynein accessory factors such as the dynactin complex affect dynein's motile behavior as defined by its velocity, processivity and directionality (Kardon et al., 2008).

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The lab also has a strong interest in the structural basis of dynein motility.  Carter et al. (2010) has solved the first crystal structures of the dynein microtubule binding domain (MTBD).  This study together with an earlier collaborative study spearheaded by Ian Gibbons (the discoverer of dynein)(Gibbons et al., 2005) suggested that sliding of helices in dynein’s coiled coil stalk might be a mechanism for changing the affinity of the microtubule binding domain and communication with the nucleotide binding sites. We subsequently solved the first crystal structure of the entire dynein motor domain, which provided new insights into the dynein motor mechanism by revealing the architecture of the 6 AAA domains and the linker, identifying important new structural elements such as the buttress and a model for how nucleotide binding in AAA1 might cause structural changes throughout the motor  (Carter et al., 2011) (see figure below).  Subsequent higher resolution crystal structures have been obtained by the Carter and Kon/Sutoh/Kurisu laboratories.

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The lab is currently developing new systems for the expression and study of other classes of dynein and dynein related proteins, as well as dyneins from other species.  Of particular interest is obtaining complementary structural information of the dynein motor domain in other states of it’s ATPase cycle, which will provide necessary information to develop a complete understanding of the complicated dynein motor mechanism.

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See additional movies and images here.

See also web sites of former Vale lab dynein members who now have their own independant laboratories:

 

A selection of our lab's publications on dynein:

  • (pdf) - Cho, C., Vale, R.D. (2012) The mechanism of dynein motility: Insight from crystal structures of the motor domain. Biochem Biophys Acta 1823: 182-191.
  • (pdf) - Carter, A.P., Cho, C., Jin, L., Vale, R.D. (2011) Crystal structure of the dynein motor domain. Science 331: 1159-1165.
  • (pdf) - Carter, A.P. and Vale, R.D. (2010) Communication between the AAA+ ring and microtubule- binding domain of dynein. Biochem Cell Biol 88: 15-21.
  • (pdf) - Kardon, J.R., Reck-Peterson, S.L. and Vale, R.D. (2009) Regulation of the processivity and intracellular localization of S. cerevisiae dynein by dynactin. Proc Natl Acad Sci USA 106: 5669-74.
  • (pdf) - Kardon, J.R. and Vale R.D. (2009) Regulators of the cytoplasmic dynein motor. Nature Rev Molec Cell Biol 10: 854-865.
  • (pdf) - Cho, C., Reck-Peterson, S.L., Vale, R.D. (2008) Regulatory ATPase sites of cytoplasmic dynein affect processivity and force generation.  J Biol Chem 283: 25839-25845.
  • (pdf) - Gennerich, A., Carter, A.P., Reck-Peterson, S.L. and Vale, R.D. (2007) Force-induced bidirectional stepping of cytoplasmic Dynein. Cell 131: 952-965.
  • (pdf) - Reck-Peterson, S.L., Yildiz, A., Carter, A.P., Gennerich, A., Zhang, N., and Vale, R.D. (2006) Single molecule analysis of dynein processivity and stepping behavior.  Cell 126: 335-348.
  • (pdf) - Gibbons, I.R., Garbarino, J.E., Tan, C.E., Reck-Peterson, S.L., Vale, R.D., and Carter, A.P.. (2005) The affinity of the dynein microtubule-binding domain is modulated by the conformation of its coiled-coil stalk. J Biol Chem 280: 23960-23965.
  • (pdf) - Reck-Peterson, S.L. and Vale, R.D. (2004) Molecular dissection of the roles of nucleotide binding and hydrolysis in dynein's AAA domains in Saccharomyces cerevisiae. Proc Natl Acad Sci USA 101: 1491-1495.

Early Work on Dynein

  • (pdf) - Vale, R.D., Malik, F. and Brown, D. (1992) Directional instability of microtubule transport in the presence of kinesin and dynein, two opposite polarity microtubule motor proteins. J Cell Biol 119: 1589-1596.
  • (pdf) - Vale, R.D., Soll, D.R., and Gibbons, I.R. (1989) One-dimensional diffusion of microtubules bound to flagellar dynein. Cell 59: 915-925.
  • (pdf) - Vale, R.D. and Toyoshima, Y.Y. (1989) Microtubule translocation properties of intact and proteolytically digested dyneins from Tetrahymena cilia. J Cell Biol 108: 2327-2334.
  • (pdf) - Vale, R.D. and Toyoshima, Y.Y. (1988) Rotation and translocation of microtubules in vitro induced by dyneins from Tetrahymena cilia. Cell 52: 459-469.

 

 

updated 5/15/2012