Assembly of the contractile ring for cytokinesis

Cytokinesis is the final step in cell division when a dividing cell physically separates into two. During cytokinesis, animals and fungi assemble a contractile ring containing actin filaments and the motor protein myosin to separate into two daughter cells. Despite huge progress in identifying most major protein components, many aspects of the physical mechanism of contractile ring assembly and constriction remain unclear. To better understand this process, we are developing models of ring self-organization, in collaboration with experimentalists.

In fission yeast, membrane-bound nodes containing myosin are broadly distributed around the cell equator. They assemble into a contractile ring through stochastic motions, after a meshwork of dynamic actin filaments appears. Analysis of node motions and numerical simulations supported a "search, capture, pull and release" mechanism whereby transient connections are established when myosins in one node capture and exert force on actin filaments growing from other nodes.

        

             

References

  1. T. C. Bidone, H. Tang, D. Vavylonis, "Dynamic Network Morphology and Tension Buildup  in 3D Model of Cytokinetic Ring Assembly," BIOPHYS. J. 107:2618-2628 (2014) .
  2. D. Laporte, N. Ojkic, D. Vavylonis and J.-Q. Wu, "alpha-Actinin and fimbrin cooperate with myosin-II to organize actomyosin bundles during contractile-ring assembly," MOL. BIOL. CELL, 23:3094-3110 (2012)  
  3. N. Ojkic, J.-Q. Wu and D. Vavylonis, "Model of Myosin Node Aggregation into a Contractile Ring: the Effect of Local Alignment," J. PHYS.: CONDENS. MATTER special issue on Cooperative Dynamics in Cells, 23, 374103 (2011).
  4. N. Ojkic and D. Vavylonis, "Kinetics of Myosin Node Aggregation into a Contractile Ring," PHYS. REV. LETT., 105 048102 (2010). (Indexed in Virtual Journal of Biological Physics Research).
  5. T. Drake and D. Vavylonis, "Cytoskeletal Dynamics in Fission Yeast: A Review of Models for Polarization and Division," HFSP J., 4 122-130 (2010). (Indexed in Virtual Journal of Biological Physics Research).
  6. D. Vavylonis, J.-Q. Wu, S. Hao, B. O'Shaughnessy, and T. D. Pollard, "Assembly Mechanism of the Contractile Ring for Cytokinesis by
    Fission Yeast," 
    SCIENCE, 319 97-100 (2008). (Evaluated in Faculty of 1000)