Fig. 1 Localization of actin and myosin II in keratocytes by fluorescence microscopy. Actin (cyan) and myosin (red) distributions are revealed by TRITC-phalloidin and indirect immunofluorescence staining, respectively. Overall actin and myosin II organization in a typical wing-shaped locomoting cell (a), enlarged portion of another cell exhibiting various patterns of actin and myosin mutual arrangement (b), locomoting cell of a symmetrical shape (c) and a tethered cell (d) are shown. All cells exhibit discrete myosin spots among continuous actin network in lamellipodia and accumulation of both actin and myosin at the lamellipodia/cell body boundary. Intensity profiles of actin (cyan) and myosin (red) within the cell area indicated in "merge" panel of (a) are shown in the inset and illustrate reverse gradients of actin and myosin in lamellipodia. (b) shows examples of a myosin spot in the lamellipodia that does not coincide with any discrete actin structure (arrowhead), myosin spots coinciding with small actin bundles merging to boundary bundles (small arrow), and co-localization of actin and myosin in the boundary bundle (large arrow). Bars, 2 µm.