Figure 5

Actin waves in PTEN-null cells expressing LimEΔ-GFP to label actin filaments. The mutant cells were pre-treated with 5 μM latrunculin A similar to GFP-PTEN expressing cells. A, characteristic actin patterns selected from a continuous recording of a single cell. B, actin network structures. Left panel: increased brightness renders the loose network in front of the wave visible, but the area circumscribed by the wave is overexposed. Middle: at lower brightness, the dense network in the inner territory and clusters within the wave zone are resolved. Right: toroid-like stage showing disruption of the actin network in the central area. C, initiation and propagation of a wave front scanned along the line indicated in the 659 s frame of (A). D, the first actin wave initiated in another cell that recovers from treatment with latrunculin A. E, line scan through the site of wave initiation as indicated in the 667 s frame of (D). Numbers in (A) to (C) indicate seconds after the beginning of Additional file 5, numbers in (D) and (E) of Additional file 6. F, speed of propagation of the wave fronts along the scans in C, (black curve) and E, (gray curve). Arrowheads indicate arrival of the wave front at the cell perimeter; subsequently wave propagation causes slow expansion of the substrate-attached cell surface. Jumps in wave propagation are due to the deposition of new actin clusters at the wave front, as seen in the Movies. Bars, 10 μ m in (A) and 5 μ m in (D).