Fibrinogen degradation depends on MMPs and myosin IIA activity. Mks were spread on 100 μg/mL 488-labeled fibrinogen-coated surfaces (green) for 3 hours and stained for F-actin (red) in the presence of (A) 0.1% DMSO as control for (B) 5 μM GM6001 and (C) 10 μM blebbistatin. (D) MYH9^−/− Mks were spread on 488-labeled fibrinogen-coated surfaces. Pictures show from left to right the merge of F-actin and fibrinogen, with red squares indicating magnified areas of F-actin and fibrinogen and dotted lines marking the outline of the cell. (E) The percentage of Mks that were degrading fibrinogen was analyzed and (F) the percentages of total degradation were measured and normalized. Black columns represent inhibitor-treated samples, and white columns represent control and MYH9^−/− Mks. Images were taken with a confocal microscope using a 60× objective. A total of 20 cells were analyzed per experiment for n = 6 experiments. Scale bars represent 10 μm. Statistical analysis was done with a Student t test. Asterisk represents significant difference with a P value < .05. Error bars indicate ±SEM. Blebb., blebbistatin; KO, knockout.