Figure 3.

Myosin clusters grow through net association of myosin to existing clusters without myosin motor activity. (A) Snapshots of myosin clusters after washing out Y-27632 from Y-27632/blebbistatin treated cells. Time after washout is shown on the top left corner of each image. Inset shows zoom-in of myosin clusters in the red squares. Images are inverted. Scale bars, 10 μm and 2 μm (inset). (B) The sum of intensities of all myosin clusters in the cell, normalized to their intensities before washout. n = 3 cells. (C) Kymograph of myosin clusters along the green line in the inset in (A). Yellow asterisks indicate representative myosin clusters that transiently appear in the field of view. Horizontal axis represents time and vertical axis represents spatial position. Timescale 5 min and spatial scale 1 μm. (D) Close-up snapshots of myosin cluster growth over time. Top left indicates time after washout. Arrowheads indicate trackable myosin clusters over time. (E) Schematic of myosin association to existing clusters. To see this figure in color, go online.