Fig. 2. Detection of GTP-bound Rab5 in living cells. CFP-Rab5, CFP-Rab5(Q79L) or CFPRab5(S34N) were co-expressed with R5BDYFP or YFP-R5BD in PAE/EGFR cells. YFP, CFP and FRET images were obtained from living cells at RT. FRET^C was calculated as described in Materials and Methods, and presented as pseudocolor images. Insets show an enlargement of the outlined regions. A.l.u.f.i., arbitrary linear units of fluorescence intensity. Bar, 10 µm.