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Fig. 5. Bulging and fission of the liquid-ordered (l_o) phase in giant unilamellar vesicles (GUVs) does not depend on cholera toxin binding. Confocal images of GUVs containing cholesterol, cholesteryl sulfonate, lophenol or lanosterol were prepared as in Fig. 2 but were labeled with DiI-C₁₈ (red) and perylene (blue). Small images show single channels only; large images are overlays. (Bottom Left) The time-lapse series shows budding of a complete l_o domain to the outside of a lophenol-containing GUV. (Bottom Right) The time series demonstrates that budding of an l_o phase domain to the inside (arrow) is accompanied by bulging of another l_o phase domain to the outside (arrowhead). Budding was induced by injection of 26 mM sucrose. (Scale bar: 10 mm.)

Fig. 6. 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI-C₁₈) and 4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-dodecanoate (BODIPY-Chol) show preferential partitioning into the same phase. Confocal images of GUVs containing dioleoyl-phosphatidylcholine (DOPC), N-stearoyl-d-erythrosphingosylphosphorylcholine (SM), and a sterol: cholesterol, lanosterol, cholesteryl sulfonate, or lophenol. Labels are DiI-C₁₈ (red) and BODIPY-Chol. Images in Center and Right show single channels; Left images are overlays. (Scale bar: 10 mm.) Preference of BODIPY-Chol for one phase is less pronounced than that of DiI-C₁₈, in particular in lanosterol-containing GUVs. Qualitatively, however, both fluorescent probes prefer the same phase. For lanosterol, the weak difference in partitioning of BODIPY-Chol between the domains is better seen with a rainbow color palette (Center Inset). Signal strength: blue, low; green, medium; red, strong.