Figure 6: Motor-induced mechanical stresses in contractile rings.
From: Still and rotating myosin clusters determine cytokinetic ring constriction
(a) Calculated stress σ as a function of myosin activity α undergoing a stationary (blue) or oscillatory (pink) instability. σhom is the stress in homogeneous state. (b) Illustration of the stress profiles for pairs of a polar and a bipolar filament (left), two bipolar filaments (middle) and two polar filaments of opposite orientation (right). Stress is drawn to scale. Only motors crosslinking two filaments are shown. (c,d) Laser ablation of cytokinetic rings in mammalian cells (c) and in fission yeast (d). (c) Ring opens on cutting. Overlay (9 frames, 0.8 s) reveals constriction and radial movement of myosin clusters. Scale bar, 5 μm. (d) The ring breaks after cutting (arrows) but is repaired within seconds. Image smoothed with ImageJ. Scale bar, 2 μm.
