Inclusions possess lower FRET efficiency than host cell membranes. Chlamydia -infected HeLa cells stained with TFSM 1 (BODIPY-FL: Donor/AF546: Acceptor) were 4-fold expanded. FRET efficiency in regions containing an inclusion (white circles) or host cell membranes was determined by acceptor photobleaching. n = 3. Scale bars: 20 µm (with 4-fold expansion factor ~ 5 µm).
