Time lapse of Rac activation followed by fast fluorescence lifetime imaging microscopy (FLIM)

Rac activation is visualized by the relative number of interacting particles (NP = I₀ x mf_D) of eGFP-Rac that undergoes Förster resonance energy transfer (FRET) with PBD-mCherry as described in Figure 8. I₀ and mf_D were obtained with the TriM-FLIM (five time-gated images of 2 nsec each; 5-sec acquisition time per NP image; time-lapse duration: 100 sec). The dimensions of the micrograph are 16 x 15 μm. [Supplemental movie from Imaging: A Laboratory Manual, Cold Spring Harbor Laboratory Press.]