Figure 3.

Migrasomes form more when cells migrating faster regardless of their migration persistence. (A) Representative images from time-lapse videos of an L929 cell expressing TSPAN4-GFP. The left panel shows an example of a slow persistent migrating cell, and the right panel shows an example of a fast persistent migrating cell; red and blue lines indicate the start and end positions of the migrating cell, respectively; yellow arrows indicate the position of migrasome formation; and black outline arrows indicated the displacement of the migrating cell. Scale bar, 20 µm. (B) Quantification of average speed of straight-moving cells in the same culture condition. n = 200 cells. (C) Quantification of the number of newly formed migrasomes per cell in straight-moving cells. n = 39 cells. (D) Quantification of the number of newly formed migrasomes per 100-µm RF trajectory in straight-moving cells. n = 39 cells. (E) Quantification of the RF trajectory length per cell in straight-moving cells. n = 39 cells. (F) Quantification of the number of parental RFs per cell in straight-moving cells. n = 39 cells. (G) Quantification of the number of newly formed branch points and tips per cell in straight-moving cells. n = 39 cells. The fitting lines are indicated by the blue dashed line, and the fitting equations are listed in each panel from C to G, with goodness of fit R² and uncertainty of the fitting slope U to define the correlation coefficient. (H) Representative images from time-lapse videos of WT L929 cells. The left panel shows an example of a slow persistent migrating cell, and the right panel shows an example of a fast persistent migrating cell; red and blue lines indicated the start and end position of the migrating cell, respectively; red circles indicate migrasomes; yellow arrows indicate the position of migrasome formation; and black outline arrows indicated the displacement of the migrating cell. Scale bar, 20 µm. (I) Quantification of average speed of straight-moving WT L929 cells in the same culture condition. n = 41 cells. (J) Quantification of the number of newly formed migrasomes per cell in straight-moving cells. n = 43 cells. (K) Quantification of the number of newly formed migrasomes per 100-µm RF trajectory in straight-moving cells. n = 44 cells. (L) Quantification of the RF trajectory length per cell in straight-moving cells. n = 39 cells. (M) Quantification of the number of parental RFs per cell in straight-moving cells. n = 41 cells. (N) Quantification of the number of newly formed branch points and tips per cell in straight-moving cells. n = 41 cells. The fitting lines are indicated by blue dashed line, and the fitting equations are listed in each panel from C–G and J–N with goodness of fit R² and uncertainty of the fitting slope U to define the correlation coefficient. The data for quantification in C–G and J–N are from n = 3 independent experiments.