Table I.

Parameters of the simulation

Total time5,000 s
Viscosity0.1 pN s/µm2100x water
Amount200Kept constant by nucleation
Steric repulsionRadius 0.025 µm(Mitchison et al., 2004)
 Stiffness 500 pN/µm every 0.25 µm
Bundling attractionRadius 0.045 µm
 Stiffness 50 pN/µm every 0.25 µm
Plus-end assembly speedsGrowth 0.18 µm/s (10.8 µm/min)(Carazo-Salas et al., 2001;
 Shrinkage 0.33 µm/s (19.8 µm/min) Tirnauer et al., 2004)
Plus-end rates, low RanGTPCatastrophe 0.1 s−1(Wilde et al., 2001;
 Rescue 0.004 s−1 Brown et al., 2007)
Plus-end rates, high RanGTPCatastrophe 0.024 s−1(Wilde et al., 2001)
 Rescue 0.018 s−1
Kinesin-5 motors
Motor domainMax speed 0.04 µm/s (2.4 µm/min)(Valentine et al., 2006;
 Stall force 5 pNKorneev et al., 2007)
 Binding range 0.05 µm
 Binding rate 2.5 s−1
 Unbinding rate 0.05 s−1
Dual-motor complexStiffness 100 pN/µmHas no binding specificity
 Resting length 0.05 µm
NuMA sphere
Radius0.025 µm
Turnover rate0.1 s−1Allows dissociation of aggregates
Binding to MT minus endMax distance 0.5 µm
 Binding rate 1 s−1
Dynein driven motilityMax speed 0.8 µm/s (48 µm/min)(Toba et al., 2006)
 Stall force 2.5 pN
 Binding range 0.05 µm
 Binding rate 0.5 s−1
 Unbinding rate 0.05 s−1
Depolymerization of MT minus-ends−0.6 µm/min per sphere
Discretization parameters
Time step0.005 s
MT section length0.5 µmFor bending elasticity
MT initial length0.1045 µmLength when created
MT minimal length0.04 µmShorter MTs are deleted