Figure 1.

(a–c) Sketch of the model. (a) A two-dimensional cross-section of the model is shown. MTs sprout from the MTOC, and their movement is confined by constraining forces from the cell membrane and the nucleus. MTs are attached to dynein motors in the IS, and they are pulled by the capture-shrinkage or the cortical sliding mechanism. (b and c) A three-dimensional sketch of the cell model is given. The outer transparent and inner spheres represent the cell membrane and the nucleus of the cell, respectively. (b) The blue disk represents the IS, where cortical sliding dynein is anchored. Small green dots in the IS represent randomly distributed dynein. (c) The brown disk represents the central region of the IS where the capture-shrinkage dynein is anchored. (d and e) A sketch of the cortical sliding mechanism (d) and the capture-shrinkage mechanism (e) is shown. Small black dots on the membrane: dynein anchor points, small black dots on the MTs: attachment points. Note that MTs depolymerize when pulled by capture-shrinkage dynein toward the membrane. To see this figure in color, go online.