Inhibition of myosin II after treatment with blebbistatin. (A) Observation of Myo2-GFP (green) and membranes labeled with FM4-64 (red) after inhibition of myosin II with blebbistatin. MeOH alone as a control (top) and 1 mM blebbistatin (bottom). Bar, 10 µm. (B) Concentration of Myo2-GFP in constricting rings in medium sized cells (mean initial circumference = 25 µm) treated with MeOH alone (red, n = 27, top panel insert) or 100 µM blebbistatin (blue, n = 20, bottom panel insert) expressed in relative units of fluorescence intensity per confocal volume; error bars represent the standard deviation from the mean. Bar, 10 µm. Asterisk indicates statistical significance (unpaired t test; P < 0.0001). (C) Average rate of constriction in medium-sized cells (mean initial circumference = 25 µm) in cells treated with MeOH alone (red, n = 26) or 100 µM blebbistatin (blue, n = 22); error bars represent the standard deviation from the mean. Asterisk indicates statistical significance (unpaired t test, P < 0.0001). See also Video 5. (D) Average rate of constriction in medium-sized cells (mean initial circumference = 25 µm) of the Myo2-GFP homokaryon (red, n = 10), Myo2-GFP heterokaryon (blue, n = 11), and Lifeact-GFP (green, n = 38) strains; error bars represent the standard deviation from the mean. Asterisk indicates statistical significance (unpaired t test, P < 0.0001). (E) Concentration of Myo2-GFP in the Myo2-GFP homokaryon (red triangles, n = 25) and Myo2-GFP heterokaryon (blue circles, n = 22) expressed in relative units of fluorescence intensity per confocal volume, as a function of hyphal circumference.