Fig. 4. Mitogen-stimulated activation of H-Ras on the PM and Golgi. COS-1 cells were transiently co-transfected with GFP-RBD (51-131) and H-Ras. 24 h after transfection, cells were serum-starved overnight and live-cell imaging was performed at 37°C. Digital images of a single cell were obtained before and after stimulation with EGF, as indicated, with identical acquisition settings. The nucleus (N) is marked. The arrow indicates activated regions of the PM and the arrowhead indicates the position of the Golgi. Figure reproduced with permission from the Nature Publishing Group (http://www.nature.com/ncb/) (Chiu et al., 2002).