Localization of SUT-GFP-fusion proteins in tobacco leaf protoplasts. Confocal images of transformed protoplasts, chloroplasts false-colored magenta. A, C, and E, SUT-GFP merged with chloroplast fluorescence. A, SbSUT1-GFP (endomembrane localized fluorescence is also present; darts). C, SbSUT4-GFP. E, SbSUT5-GFP. Plasma membrane localization was observed in merged images A and E, where chloroplasts were positioned on the cytoplasmic side of the GFP fluorescence (arrows). Tonoplast localization was observed in C, where the GFP-fluorescent tonoplast was positioned on the cytoplasmic side of the chloroplast (arrow). B, AtPTR1-GFP plasma membrane control. D, AtPTR2-GFP tonoplast control. GFP excitation, 473 nm; emission, 487 to 521 nm. Chloroplast excitation, 559 nm; emission, 606 to 673 nm. Bar = 10 µm.