Short- and long-term memory of moving amoeboid cells
Fig 2
Cells memorize the position of splitting pseudopods.
Analysis of four consecutive pseudopods of which P1 to P3 are three splitting pseudopods and P0 can be a splitting or a de novo pseudopod. a. Schematic for the analysis of pseudopod vectors with polar coordinates (results presented in panels b-e). All four pseudopods are rotated such that P1 directs at 0 degrees, and if needed reflected around the Y-axis such that P1 directs to the right relative to P0; finally P1 to P3 are transposed so that they start in the origin. Panels b-e: direction of P1 (black dot; 0 degrees by definition), P2 (blue dots) and P3 (green dots). The cosine of the angle between P1 and P3 (cos(ϕ1,3), yellow dots) indicates the persistence of splitting pseudopods. b, c. Wild-type, n = 322: P2 is extended at -55 ± 62 degrees and P3 at 2 ± 40 degrees relative to P1; cos(ϕ1,3) = 0.78. d, e. mutant SCAR-SD lacking positional memory, n = 155: P2 is extended at -17 ± 67 degrees and P3 at -1 ± 90 degrees relative to P1; cos(ϕ1,3) = 0.25. The data are means and SD.