Calcium wave and actin flow progress in synchrony toward the wound margin. (A) High magnification stills of a pupal notum expressing G-CaMP3-GFP and mCherry-Moesin under the control of pnr-GAL4 in the early seconds of wound healing. After the initial spreading, a wave of high intracellular calcium progresses toward the wound in synchrony with the actin wave, culminating in actin cable formation. A dashed white line marks the wound margin. Bar, 10 µm. (B) Kymograph showing the progression of the calcium wave (white arrowheads) immediately behind the actin flow in the early seconds of wound healing. First detection of the actin flow (dashed lines in Distance and Time) occurs in a region of optimal calcium concentration immediately next to a region of highest concentration. Red line in the Time axis highlights the delay between the initiation of the calcium wave and first detection of the actin flow. Asterisk indicates the actin cable. (C) Graphs representing the variation of G-CaMP3-GFP and mCherry-Moesin intensity with wound distance in the first 1,200 s of wound healing. Peaks of high intracellular calcium levels correspond to low actin intensity. The actomyosin flow is formed in cells that exhibit intermediate calcium levels and travels ahead of the calcium wave culminating in actin cable formation. Asterisks in the G-CaMP3 curves indicate position of the actin flow in the same tissue region, at the same time.