Table I.

Parameters of the simulation

Parameter descriptionSymbolValue or range of values
Model-specific parameters
Time stepdt10−2 s
Filament sectionR1.2 μm
Simulation boxsquare, 60 × 60 μm
Fixed parameters
Total simulated time1,000 s
TemperaturekBT4.2 × 10−3 pN μm
Fluid viscosityviscosity0.05 pN s/μm2
Microtubule's bending modulusE20 pN μm2
Microtubule dynamic instability: catastrophe and rescue frequenciesrescue in s−1, (13 − L) × 0.0033; catastrophe in s−1, L × 0.003a
Growth and shrinking speeds+10 and −15 μm/s
Complexes diffusionD20 μm2/s
Independently varied parameters
Number of microtubules per asterbetween 20 and 80, same for both asters
Motor links rigidityKbetween 5 and 60 pN/μm
Number of complexes: one parameter in screens 3a, b, and c,
 and two parameters in screens 1 and 2between 500 and 15,000
Motor's speed (2 parameters)Vmaxbetween −1 and +1 μm/sb
Motor's stalling force (2)Fmaxbetween 0.5 and 2 pN, with Fmax2 > 9.dim.K.kBT
Motor's binding rate (2)Ponbetween 0.04 and 50 s−1
Motor's unbinding rate (2)Poffbetween 0.04 and 50 s−1
Motor's unbinding rate from microtubule endPendPend > 100 s−1 in screens 1, 2, and 3a, and 0.04 to 50 s−1 in screens 3b and c
Motor's force–velocity type (2)one of four models (see Materials and methods)
Derived parameters
Motor's reach distanceϵequals Fmax/K (see Materials and methods)
  • a L, length of microtubule in μm.

  • b Vmax is rounded to a multiple of 0.01 and Vmax = 0 is excluded.