Studying the Balance of Forces in the Mitotic Spindle with Computer Simulations


François Nédélec, Cell Biology and Biophysics. EMBL, Heidelberg, Germany.


For their division, eukaryotic cells need to produce opposite forces on each pair of sister chromatins to ultimately segregate them. These forces are applied through a structure, called the mitotic spindle, made of chromosomes, microtubules and many other proteins of the cytoskeleton. The spindle is not a static structure but rather a dynamic steady state which can however pull with continuous forces on the chromosomes. Essential to the self-organization of the spindle are the molecular motors, which can bind and move on the microtubules. I have used simulations to explore if a dynamic equilibrium can be produced solely by motor proteins between two asters of microtubules. Computers are used to systematically explore the space of reasonable parameter values, and yield several possible ways to build equilibrium. With the kind of motors found, microtubules will automatically organize into a stable and sustained equilibrium with great internal tension.


Ref: computer simulations reveal motor properties generating stable anti-parallel microtubule interactions. François Nédélec, Journal of Cell Biology, Sept 2002.