Many important subcellular cargos are transported along the microtubule cytoskeleton by groups of kinesin and/or dynein motor proteins. Specific proteins and cargos that are implicated in diseases, particularly neurodegeneration, are known to interact with multiple motor molecules, and hence, there are likely strong links between collective motor function and human diseases. The grouping of motors is believed to be important for specific transport challenges that may require high force production. Furthermore, many cargos bind to kinesin and dynein and move bidirectionally along microtubules. This behavior is known to influence the spatio-temporal evolution and final distributions of cargos in cells. Yet, mechanisms governing collective motor transport are not well understood, and overall, existing methods to investigate these problems are limited by inabilities to precisely characterize or control the number of motors on cargos. This project addresses these issues by building upon our newly developed biosynthetic strategies to create structurally- defined systems of interacting motor molecules, and biophysical assays that allow collective motor dynamics to be monitored at the single-molecule level. By combining these capabilities, we have established that interactions among multiple kinesin-1 molecules contribute significantly to collective transport behaviors (e.g., cargo run lengths, and force production), and that despite their abilities to produce large forces, groups of kinesin motors tend to cooperate negatively. The proposed work will employ our synthetic technologies along with precision particle tracking and optical trapping methods to further evaluate the extent to which negative cooperativity influences cargo transport by multiple kinesins in cells (Aim 1). We will also examine analogous cooperative effects in motor systems composed of multiple dynein molecules (Aim 2). Both of these studies will draw connections between the properties of individual motor molecules, the nature of inter-motor interactions within motor assemblies, and collective transport parameters. In each case, multiple-motor functions will be evaluated using theoretical models that can account for all relevant biochemical states of individual motors as well as microtubule-bound configurations of motor assemblies. Finally, we will perform assays that monitor the motions of structurally-defined motor assemblies composed of kinesin and dynein molecules (Aim 3). Here, knowledge of collective behaviors among each class of motors, coupled with the ability to systematically investigate the influence of motor number and ratio on bidirectional cargo motility, should allow bidirectional transport mechanisms to be resolved. Overall, the proposed study will help to clarify observations of kinesin and dynein's apparent functional interdependence in cells, and provide new abilities to examine and interpret how defects in motor function influence intracellular transport processes.

Public Health Relevance

Resolving mechanisms of collective motor transport will provide a foundation to interpret how transport defects, genetic and/or environmental, influence the function of motor molecules in cells. Outcomes from this work may also suggest new methods to develop and evaluate therapeutic agents directed at molecular motors.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM094489-04
Application #
8496827
Study Section
Macromolecular Structure and Function C Study Section (MSFC)
Program Officer
Gindhart, Joseph G
Project Start
2010-07-01
Project End
2015-06-30
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
4
Fiscal Year
2013
Total Cost
$271,962
Indirect Cost
$85,669
Name
Rice University
Department
Biomedical Engineering
Type
Schools of Engineering
DUNS #
050299031
City
Houston
State
TX
Country
United States
Zip Code
77005
Valleriani, Angelo; Li, Xin; Kolomeisky, Anatoly B (2014) Unveiling the hidden structure of complex stochastic biochemical networks. J Chem Phys 140:064101
Li, Xin; Kolomeisky, Anatoly B; Valleriani, Angelo (2014) Stochastic kinetics on networks: when slow is fast. J Phys Chem B 118:10419-25
Li, Xin; Kolomeisky, Anatoly B; Valleriani, Angelo (2014) Pathway structure determination in complex stochastic networks with non-exponential dwell times. J Chem Phys 140:184102
Rogers, Arthur; Constantinou, Pamela E; Jamison, D Kenneth et al. (2014) Construction and analyses of elastically coupled multiple-motor systems. Methods Enzymol 540:189-204
Efremov, Artem K; Radhakrishnan, Anand; Tsao, David S et al. (2014) Delineating cooperative responses of processive motors in living cells. Proc Natl Acad Sci U S A 111:E334-43
Li, Xin; Kolomeisky, Anatoly B (2013) Mechanisms and topology determination of complex chemical and biological network systems from first-passage theoretical approach. J Chem Phys 139:144106
Kolomeisky, Anatoly B (2013) Motor proteins and molecular motors: how to operate machines at the nanoscale. J Phys Condens Matter 25:463101
Jamison, D Kenneth; Driver, Jonathan W; Diehl, Michael R (2012) Cooperative responses of multiple kinesins to variable and constant loads. J Biol Chem 287:3357-65
Kolomeisky, Anatoly B (2011) Physics of protein-DNA interactions: mechanisms of facilitated target search. Phys Chem Chem Phys 13:2088-95
Akimov, Alexey; Kolomeisky, Anatoly B (2011) DYNAMICS OF SINGLE-MOLECULE ROTATIONS ON SURFACES DEPEND ON SYMMETRY, INTERACTIONS AND MOLECULAR SIZES. J Phys Chem C Nanomater Interfaces 115:125-131

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