Fig. 5
From: Steering cell migration by alternating blebs and actin-rich protrusions
Modulating the ratio of tumbling to run times affects migration precision. a Positional variance of CAEzrin-expressing and ezrin-MO cells after approximately 2 hours of migration. Values are the ratio relative to transplanted control cells in the same embryo (internal controls) to account for experimental variability between different embryos. b Schematic of chemotactic run-and-tumble migration: a cell (black) migrates towards a moving target (orange) via runs and tumbles of duration τr and τt, respectively. After each tumble, the cell redirects towards the target. The target moves with a velocity v target, and d is the initial cell-target distance. We evaluate the distance to the target after, te = 1.5 h. Simulation results for migration precision versus τr/τr, exp; τr is the run time in the model and τr, exp is the τr value extracted from fitting the model to experiments. Other parameters were chosen based on experimental measurements (Additional file 1: Supplementary Methods). Each point results from 100 simulations. Blue curve (d(t e )): mean target distance at time t e . Red curve: spatial dispersion of cells at t e . The blue shaded region corresponds to the range of τr, compatible with experimental observations (Additional file 10: Figure S4F, Additional file 1: Supplementary Methods). c Two-dimensional probability density of alignment and scaled speed, P(A,S), obtained from simulation of n = 23 model cells using parameters matching experimental data (Additional file 1: Table S1). The blue dashed line shows the linear fit to the maximum values of P(A,S) for A. The red dashed line is the line, perpendicular to the maximum, defining the threshold above which a portion of a trajectory is considered to be a run phase. d One-dimensional cross-section of P(A,S) along the maximum line from simulated cell trajectories in blue (c) and from experimental trajectories of controls transplanted into MZoep hosts in black (data from Fig. 1h). Red dashed line as in c. e Speed distributions P(|v|) during runs and tumbles. Comparison of experimental controls transplanted into MZoep hosts (crosses/solid lines) and model results (circles/dashed lines) for a single simulation run using parameters in Additional file 1: Table S1