Myosin X meanders symmetrically along fascin-actin bundles. (a) Scatter plot of the x and y components for all steps on fascin-actin bundles (n = 379). Steps occur either along the x axis (solid diamonds, n = 161), along the y axis (open circles, n = 135), or in one of the four Cartesian quadrants (open triangles, n = 83). Quadrants are noted with Roman numerals. (b) Histogram of y step-sizes with no corresponding x step-size (n = 135; 68 positive y step-sizes, 67 negative y step-sizes). (c) Histogram of x step-sizes with no corresponding y step-size (n = 161; 137 positive x step-sizes, 24 negative x step-sizes). (d) (Top) Histogram of x step-sizes of concurrent steps with a positive y step-size (n = 45; Quadrants I and II, n = 37 and n = 8, respectively). (Bottom) Histogram of x step-sizes of concurrent steps with a negative y step-size (n = 38; Quadrants III and IV, n = 7 and n = 31, respectively). (e) (Left) Histogram of y step-sizes of concurrent steps with a negative x step-size (n = 15; Quadrants II and III, n = 8 and n = 7, respectively). (Right) Histogram of y step-sizes of concurrent steps with a positive x step-size (n = 68; Quadrants I and IV, n = 37 and n = 31, respectively). Note that the motor takes steps to the left or right (up or down, as plotted) at nearly equal frequencies.