Fig. 4. Functional analysis of cofilin during acute actin signalling. (A) Actin staining in dsRNA-treated cells stimulated with insulin. S2R⁺ cells were incubated with dsRNAs targeting LacZ, cofilin, LIMK, Ssh, Rac1and Rac2 (Rac1/2) and Arp3 for 5 days. On day 5, cells were treated with insulin for 10 minutes (10') or left untreated (0'). Cells were then fixed and stained for F-actin with Rhodamine-phalloidin. Bars, 50 µm. (B) Visualisation of actin dynamics in dsRNA-treated cells using GFP-labelled moesin. Snapshots of time-lapse movies just before the addition of insulin are shown on the left. Bars, 50 µm. The two lines used to generate the kymographs (right) are indicated on the cell images. Actin reorganisation was filmed for 3 minutes before and for 10 minutes after the addition of 10 µg/ml insulin, the point of insulin addition labelled as 0'. Images are representative of at least two independent experiments.