Fig. 1
Liposomes containing endosomal SNAREs are targeted to their endogenous counterparts. a Schematic overview showing the organelle-specific markers used in this study. See text for abbreviations. b Representative confocal microscopy images of HeLa cells fixed 5 min after injection of Alexa Fluor 488-Tfn-labeled endosomes and DAPI (injection marker). Cells were immunolabeled for organelle markers except Alexa Fluor 568-Tfn that was internalized into the cells during microinjection for 5 min. Inserts show high magnifications of the boxed areas. White arrows indicate co-localization. Scale bar, 10 µm. c Co-localization between injected early endosomes and endogenous markers (in % of all labeled injected endosomes). In this and all subsequent figures, the data show mean values ± S.E.M. of 3–15 independent experiments. At least 100 injected vesicles were analyzed for the colocalization with each organelle marker in an experiment of microinjection. Scale bar, 10 µm. Stars indicating significance: *P < 0.05, **P < 0.01, ***P < 0.001, all determined by unpaired t-test. d Co-localization between injected late endosomes and endogenous markers (in % of injected endosomes). e Representative confocal images of cells fixed 5 min after injection of proteoliposomes (PLs) reconstituted with early endosomal SNAREs (4-EE-SNARE PL). White arrows indicate co-localization between injected liposomes and organelle markers. Scale bar, 2.5 µm. f Co-localization between injected liposomes containing either four early endosomal SNAREs (4-EE-SNARE PL, light blue), or four late endosomal SNAREs (4-LE-SNARE PL) (light pink), respectively, and endogenous markers. Values were normalized to the degree of co-localization observed in control injections using protein-free liposomes
