Molecular motors--kinesin and myosins--play a crucial role in the maintenance and development of the organization, motility, and signaling of healthy cells. Central nervous-system disorders, such as Alzheimer's disease and certain types of cancer, all arise from molecular motors gone awry. There are, however, several fundamental questions about how kinesin-1 moves. (Kinesin-1 is the "standard-bearer" of kinesins.) Also largely unknown is how Myosin VI moves. To answer these questions we will address the motors at the in vitro, single molecule level. We will apply a number of single molecule tools, including some that have been developed in the first 4 years of this proposal. We will use FIONA (Fluorescence Imaging with One Nanometer Accuracy), DOPI (Defocused Orientation and Position Imaging), and SHREC (Single Molecule High REsolution Colocalization). The theme of the kinesin part is: how is motility affected by each of kinesin's parts, including the head, the coiled-coil, and the tail? The theme of the myosin VI part is: how does such a small motor take such a large step? We will present unpublished data which suggests that kinesin is bound by both heads during a run, making the probability of falling off very low. We will also suggest that the large non-helical region in kinesin-1's coiled-coiled region allows this motor to walk in an "asymmetric fashion," allowing the cargo to point forward. Finally, we will suggest that full-length kinesin takes "pauses" due to the tail-region folding over and interacting with the head region and possibly the microtubule. With regards to myosin VI, we have an enormous amount of preliminary data. It will suggest that the head undergoes a 180? swing during the powerstroke. Furthermore, we suggest that a 3-helix motif in the lever arm uncoils and creates an unprecedented 24 nm extension, which allows the motor to take a 36 nm step.

Public Health Relevance

Molecular motors have the job of moving and organizing organelles within a cell. Problems within the motors cause brain cancer, Alzheimer's disease, etc. We seek to understand the basic workings of kinesins and myosin VI, two important motors.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM068625-08
Application #
8217276
Study Section
Macromolecular Structure and Function C Study Section (MSFC)
Program Officer
Lewis, Catherine D
Project Start
2004-06-01
Project End
2014-01-31
Budget Start
2012-02-01
Budget End
2014-01-31
Support Year
8
Fiscal Year
2012
Total Cost
$344,761
Indirect Cost
$104,636
Name
University of Illinois Urbana-Champaign
Department
Physics
Type
Schools of Engineering
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820
Blehm, Benjamin H; Selvin, Paul R (2014) Single-molecule fluorescence and in vivo optical traps: how multiple dyneins and kinesins interact. Chem Rev 114:3335-52
DeBerg, Hannah A; Blehm, Benjamin H; Sheung, Janet et al. (2013) Motor domain phosphorylation modulates kinesin-1 transport. J Biol Chem 288:32612-21
Wang, Yong; Fruhwirth, Gilbert; Cai, En et al. (2013) 3D super-resolution imaging with blinking quantum dots. Nano Lett 13:5233-41
Liu, Yanxin; Hsin, Jen; Kim, HyeongJun et al. (2011) Extension of a three-helix bundle domain of myosin VI and key role of calmodulins. Biophys J 100:2964-73
Syed, Sheyum; Mullner, Fiona E; Selvin, Paul R et al. (2010) Improved hidden Markov models for molecular motors, part 2: extensions and application to experimental data. Biophys J 99:3696-703
Mullner, Fiona E; Syed, Sheyum; Selvin, Paul R et al. (2010) Improved hidden Markov models for molecular motors, part 1: basic theory. Biophys J 99:3684-95
Kim, Hyeongjun; Hsin, Jen; Liu, Yanxin et al. (2010) Formation of salt bridges mediates internal dimerization of myosin VI medial tail domain. Structure 18:1443-9
Reifenberger, Jeff G; Toprak, Erdal; Kim, Hyeongjun et al. (2009) Myosin VI undergoes a 180 degrees power stroke implying an uncoupling of the front lever arm. Proc Natl Acad Sci U S A 106:18255-60
Toprak, Erdal; Yildiz, Ahmet; Hoffman, Melinda Tonks et al. (2009) Why kinesin is so processive. Proc Natl Acad Sci U S A 106:12717-22
Yardimci, Hasan; van Duffelen, Marilyn; Mao, Yinghui et al. (2008) The mitotic kinesin CENP-E is a processive transport motor. Proc Natl Acad Sci U S A 105:6016-21

Showing the most recent 10 out of 23 publications