FIG. 4.

GAP-defective mutants of Abr and Bcr induce abnormally elongated morphology in a macrophage-derived cell line, RAW 264.7. Cells were transfected with the indicated plasmids. After 24 h, cells were fixed, stained for nuclei, and analyzed with a fluorescence microscope. (A) Cells were visualized for EGFP (green) and nuclei (blue). Bars, 20 μm. EGFP-Abr R683A-expressing cells are shown at a higher magnification. (B) EGFP images (green) of cells were superimposed on those of phase-contrast images (black and white) to illustrate overall cell shape. Note that some of the cells expressing GAP mutants of Abr and Bcr (arrowheads) developed a highly elongated shape or multiple protrusions, while untransfected cells (arrows) remained round.