Figure 1.

Morphology and migratory behavior of control and myosin IIB null cells. Although most control cells maintained their morphology over a 60-min period (A), mutant cells showed rapid changes in cell shape during the same period of time (B). In addition mutant cells migrate with a highly unstable polarity (B, arrows), compared with control cells (A, arrows). Images of high magnification show protrusion, elongation (C, long arrows), and rapid retraction of processes (C, short arrows). The latter creates small pieces of motile cytoplasm that litter the glass surface (C, arrowheads). Time in hours and minutes is indicated in each image. Bar, 50 μm.