Specificity of GFP–RBD-3-R59A,N64D as a reporter for Ras-GTP. COS-7 cells were transfected with GFP–RBD-3-R59A,N64D or GFP–RalGDS-RBD-3 in combination with the indicated DsRed-tagged GTPases. Cells were imaged confocally. GFP, green fluorescent protein; RBD, Ras-binding domain of the Ras effector c-Raf. Scale bars, 10 μm.