Fig. 3. Fhos in an active form localizes to actin stress fibers. (A) Confocal images of HeLa cells expressing the GFP–Fhos-NC (415-1053), a constitutively active mutant protein. Confocal images near the bottom, middle and top of the cells, as well as stacked images, are shown. For each pair of images, GFP fluorescence (left panel) and phalloidin staining (right panel) are shown. (B) Actin fibers in HeLa cells expressing the GFP-NC mutant. GFP fluorescence (left panels) or phalloidin staining (right panels) are shown. A magnified view of the insert is also shown in the lower panels. (C) COS-7 cells expressing the GFP-NC mutant were fixed and detected by GFP fluorescence (left panel) or phalloidin staining (right panel). Bar, 20 µm.