Myosin-II mutants do not bleb and their movement under an agarose overlay is impaired. (A) Cells of the parental strain, JH10, and a null mutant of myosin essential light chain (MlcE) under 1% agarose. The parental strain produces blebs (arrows), the mutant does not. (B) MlcE-null cells do not produce high-speed projections (>1.5 µm/s, equated to blebs) under a 0.7% agarose overlay (six cells analyzed using QuimP10). (C) Myosin-II null mutants move more slowly under 0.7% agarose overlays than wild-type (JH10: wild-type; MlcE: myosin essential light chain; MlcR: myosin regulatory light chain; MhcA: myosin heavy chain). (D) Myosin-null mutants do not bleb in response to uniform cyclic-AMP stimulation. Cyclic-AMP shock assay: cells under buffer were stimulated with 1 µM cyclic-AMP, and blebs counted manually (see Video 8). Under agarose migration speed: speed of cells moving under 0.7% agarose toward a well of 4 µM cyclic-AMP was measured. Bar, 10 µm.