Modeling Microtubule Dynamics in Mitosis

Summary

Principal Investigator: David J Odde
Abstract: DESCRIPTION (provided by applicant): During cell division two complete genomes are mechanically segregated via motions coupled to kinetochore microtubule (kMT) assembly and disassembly. Recently, the extent of molecular-level information relevant to the dynamics of kMTs has increased substantially with the convergence of molecular biology and high- resolution digital light microscopy of living, fluorescent protein-transfected cells. However, the dynamics of single kMTs have yet to be visualized, and so a major challenge is to develop an understanding of the mechanisms that regulate individual kMTs. Three important questions regarding kMTs and their regulation remain unanswered: 1) How do molecular components interact to achieve the overall force balance in the mitotic spindle? 2) Are plus-end directed molecular motors the main controllers of kMT assembly and chromosome congression across phylogeny and in human cells? 3) What are the nanoscale-kHz dynamics of kMT plus-ends at the kinetochore? In each case we will establish a mathematical foundation based on physical principles, implement a computer code, and compare the simulation predictions to experimental microscopy data using model-convolution to rigorously test specific hypotheses. The project will build on existing collaborations with the Bloom, Cassimeris, Salmon, and Winey/O'Toole groups, will develop new collaborations with the Berman and Hays groups, and will allow biomedical engineers to develop models in close collaboration with cell biologists so that hypotheses will be quantitatively tested against experimental data. Furthermore, the simulations will facilitate the design and development of new experiments for more effective hypothesis testing. In the end, we will combine theory with experiment to better understand the biophysical basis of MT dynamics during mitosis and associated chromosome movements. The knowledge gained through these studies will ultimately be useful in clinical applications, such as cancer treatment, because of the centrality of mitotic spindle dynamics to mitosis. Some of the more effective cancer treatments, such as taxol (paclitaxel), are based on their interference with MT-based processes during cell division. In addition, some of the proteins to be investigated, such as kinesin-5, are the targets of novel cancer therapeutics. Understanding MT dynamics and their regulation by microtubule associated proteins in mitosis will allow us to more rationally develop new cancer treatment strategies. This project will facilitate the development of a group of engineers who are interested in applying mathematics and physics to address fundamental cell biology questions in close collaboration with cell biologists. Ultimately we are driving toward reliable, predictive models for the molecular-level control of mitotic spindles so that we can control cancer progression. PUBLIC HEALTH RELEVANCE: Once chromosomes are replicated, they need to be properly segregated into each of two daughter cells. We will study the catastrophe dynamics of the "microtubule" polymers that drive proper chromosome segregation. These studies will give new insight into how cells become cancerous, and how to prevent cancer cells from proliferating.
Funding Period: 2006-01-01 - 2014-12-31
more information: NIH RePORT

Top Publications

  1. pmc Measuring nanometer scale gradients in spindle microtubule dynamics using model convolution microscopy
    Chad G Pearson
    Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309 0347, USA
    Mol Biol Cell 17:4069-79. 2006
  2. pmc Rapid microtubule self-assembly kinetics
    Melissa K Gardner
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
    Cell 146:582-92. 2011
  3. pmc Regulation of the MEX-5 gradient by a spatially segregated kinase/phosphatase cycle
    Erik E Griffin
    Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Center for Cell Dynamics, Johns Hopkins School of Medicine, 725 N Wolfe Street, PCTB 706, Baltimore, MD 21205, USA
    Cell 146:955-68. 2011
  4. pmc Modeling cellular processes in 3D
    Alex Mogilner
    Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, USA
    Trends Cell Biol 21:692-700. 2011
  5. pmc Dynein tethers and stabilizes dynamic microtubule plus ends
    Adam G Hendricks
    Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104 6085, USA
    Curr Biol 22:632-7. 2012
  6. pmc Estimating the microtubule GTP cap size in vivo
    Dominique Seetapun
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
    Curr Biol 22:1681-7. 2012
  7. pmc Evolving tip structures can explain age-dependent microtubule catastrophe
    Courtney E Coombes
    Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
    Curr Biol 23:1342-8. 2013
  8. pmc Stochastic simulation and graphic visualization of mitotic processes
    Melissa K Gardner
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
    Methods 51:251-6. 2010
  9. pmc Mps1 phosphorylation of Dam1 couples kinetochores to microtubule plus ends at metaphase
    Michelle M Shimogawa
    Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
    Curr Biol 16:1489-501. 2006
  10. ncbi Potential for control of signaling pathways via cell size and shape
    Jason Meyers
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
    Curr Biol 16:1685-93. 2006

Detail Information

Publications20

  1. pmc Measuring nanometer scale gradients in spindle microtubule dynamics using model convolution microscopy
    Chad G Pearson
    Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309 0347, USA
    Mol Biol Cell 17:4069-79. 2006
    ..The beta-tubulin mutant cells have an increased frequency of chromosome loss, suggesting that the accuracy of chromosome segregation is linked to robust kMT plus-end dynamics...
  2. pmc Rapid microtubule self-assembly kinetics
    Melissa K Gardner
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
    Cell 146:582-92. 2011
    ..We find that because both the association and the dissociation rates increase at higher free subunit concentrations, the kinetics of microtubule assembly are an order-of-magnitude higher than currently estimated in the literature...
  3. pmc Regulation of the MEX-5 gradient by a spatially segregated kinase/phosphatase cycle
    Erik E Griffin
    Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Center for Cell Dynamics, Johns Hopkins School of Medicine, 725 N Wolfe Street, PCTB 706, Baltimore, MD 21205, USA
    Cell 146:955-68. 2011
    ..The principles demonstrated here apply to any spatially segregated modification cycle that affects protein diffusion and do not require protein synthesis or degradation...
  4. pmc Modeling cellular processes in 3D
    Alex Mogilner
    Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, USA
    Trends Cell Biol 21:692-700. 2011
    ....
  5. pmc Dynein tethers and stabilizes dynamic microtubule plus ends
    Adam G Hendricks
    Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104 6085, USA
    Curr Biol 22:632-7. 2012
    ..Thus, dynein-mediated capture and tethering of microtubules at the cortex can lead to enhanced stability of dynamic plus ends...
  6. pmc Estimating the microtubule GTP cap size in vivo
    Dominique Seetapun
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
    Curr Biol 22:1681-7. 2012
    ..We speculate that a large GTP cap provides a locally concentrated scaffold for tip-tracking proteins and confers persistence to assembly in the face of physical barriers such as the cell cortex...
  7. pmc Evolving tip structures can explain age-dependent microtubule catastrophe
    Courtney E Coombes
    Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
    Curr Biol 23:1342-8. 2013
    ..These results have important consequences for catastrophe regulation in cells, as microtubule-associated proteins could promote catastrophe events in part by modifying microtubule tip structures...
  8. pmc Stochastic simulation and graphic visualization of mitotic processes
    Melissa K Gardner
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
    Methods 51:251-6. 2010
    ..By extracting key qualitative elements of the model in this fashion, model predictions and new experiments can be more easily extracted from model results...
  9. pmc Mps1 phosphorylation of Dam1 couples kinetochores to microtubule plus ends at metaphase
    Michelle M Shimogawa
    Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
    Curr Biol 16:1489-501. 2006
    ..Here we describe a phosphorylation event that promotes the coupling of kinetochores to microtubule plus ends...
  10. ncbi Potential for control of signaling pathways via cell size and shape
    Jason Meyers
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
    Curr Biol 16:1685-93. 2006
    ..However, how such systems behave theoretically when embedded in a cell of varying size or shape has not been considered...
  11. ncbi Modeling of chromosome motility during mitosis
    Melissa K Gardner
    Department of Biomedical Engineering, University of Minnesota, 7 132 Hasselmo Hall, 312 Church Street S E, Minneapolis, Minnesota 55455, USA
    Curr Opin Cell Biol 18:639-47. 2006
    ..Together, these studies facilitate advancement toward a unified model that quantitatively predicts chromosome motility...
  12. ncbi Analysis of microtubule curvature
    Andrew D Bicek
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
    Methods Cell Biol 83:237-68. 2007
    ..Finally, we discuss extensions of the method to quantify microtubule curvature in living cells...
  13. pmc Microtubule assembly dynamics at the nanoscale
    Henry T Schek
    European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117, Heidelberg, Germany
    Curr Biol 17:1445-55. 2007
    ..Here we use optical tweezers to track microtubule polymerization against microfabricated barriers, permitting unprecedented spatial resolution...
  14. pmc The microtubule-based motor Kar3 and plus end-binding protein Bim1 provide structural support for the anaphase spindle
    Melissa K Gardner
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
    J Cell Biol 180:91-100. 2008
    ..Our analysis reveals the importance of Bim1p in maintaining a stable ipMT overlap zone by promoting polymerization of ipMTs during anaphase, whereas Kar3p contributes to spindle stability by cross-linking spindle MTs...
  15. pmc Microtubule assembly dynamics: new insights at the nanoscale
    Melissa K Gardner
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
    Curr Opin Cell Biol 20:64-70. 2008
    ....
  16. pmc Chromosome congression by Kinesin-5 motor-mediated disassembly of longer kinetochore microtubules
    Melissa K Gardner
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
    Cell 135:894-906. 2008
    ..In conclusion, we find that length-dependent control of net kMT assembly by kinesin-5 motors yields a simple and stable self-organizing mechanism for chromosome congression...
  17. pmc Brownian dynamics of subunit addition-loss kinetics and thermodynamics in linear polymer self-assembly
    Brian T Castle
    Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota
    Biophys J 105:2528-40. 2013
    ..Although we utilize the specific example of the microtubule here, the findings are applicable to multistranded polymers generally...