1. PTP1B promotes persistent migration.
PTP1B promotes persistent migration. WT and KO cells were analyzed by time-lapse phase-contrast microscopy. (A) Randomly selected individual tracks of WT and KO cells were copied and combined into single panels to avoid empty spaces. Scale bar: 100 µm. (B) Phase-contrast image sequences of representative WT and KO cells. WT cells form broad and persistent lamellar extensions in the direction of migration (red arrowheads) whereas KO cells form narrow and low persistence lamellar extensions in several directions (yellow arrowheads), and frequently have long trailing tails (yellow arrows). Numbers indicate time in minutes. Scale bar: 50 µm. (C) Quantification of migration speed and directionality. Averaged speed, calculated with Metamorph software, was significantly reduced in KO cells (P<0.0001). Migration directionality was determined by calculating the D/T ratio, and by fitting the MSD to the persistent random walk model (RWM) equation. Note that D/T in WT cells is significantly higher than that in KO cells (P = 0.001). The MSD over time was used to extract values of speed (S) and persistence time (P). Data were analyzed by the Wilcoxon–Mann–Whitney non-parametric test. Bars represent the means ± s.e.m. of 29–32 cells. (D) Time plots of the migratory pattern of WT and KO cells. Advance and pause phases of each time-lapse series were color-coded (black square = advance, white square = pause; each square = time interval of 8 minutes) and arranged in a horizontal row as they occurred. Intervals with a net advance lower to 1.3 µm were considered as pauses.
Juan E. Burdisso et al. J Cell Sci 2013;126:
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