Influence of environment on the migration and scanning properties of Act cells.

<p>Effects of variations in tissue density (A-D) and in tissue rigidity (E-H) on migrating cells within the amoeboid (Max_Act = 20) and keratocyte-like (Max_Act = 80) parameter range. The results represent the average of 20 experiments of 20000 MCSs each, with a sampling time Δ<i>t</i> = 20 MCSs between consecutive measurements of cell position. In each experiment, one Act cell was placed on a dish containing non-Act cells seeded at different densities (A-D), or on a dish with non-Act cells at 100% density with different rigidities (E-H). The rigidity of the tissue formed by non-Act cells is controlled by the perimeter constraint (<i>λ</i>_Perimeter). The higher <i>λ</i>_Perimeter, the stricter cells keep to their target perimeter, and the less they tend to deform. (A, E) Migration persistence. (B, F) Instantaneous speed. (C, G) The fraction of tissue cells scanned by the Act cell. A cell is scanned if it has been in contact with the Act cell at least once. (D) Typical morphologies of Act cells (green with yellow to red protrusions) at different tissue densities. The tissue cells that have been scanned by the Act cell are colored magenta, non-scanned cells are gray. (H) (Left) Speed traces of two cells in the amoeboid range (Max_Act = 20), one migrating in flexible tissue (<i>λ</i>_Perimeter = 0) and the other one in rigid tissue (<i>λ</i>_Perimeter = 10). The red dashed lines delimit the speed thresholds under which the cells were considered stationary. (Right) Boxplots of the stop durations (in MCSs) corresponding to the speed traces in the left panel. Yellow stars indicate means. See <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004280#sec010" target="_blank">Methods</a> section for a more detailed explanation of the experiments and for the complete list of parameter values.