Figure 6.

Effect of hypertonic sucrose and cytosol acidification on the endocytic trafficking of GLUT4 and transferrin. Cells were incubated with either anti-myc mAb 9E10 (A, B, E, and F) or Texas red–coupled transferrin (C and D) for 2.5 h at 15°C, and then shifted to 37°C for 10 min in either hypertonic medium containing 0.45 M sucrose (A–D) or in regular medium acidified with acetic acid (E and F). Processing for laser confocal microscopy was as in Fig. 4. Note that in the presence of sucrose and acetic acid, GLUT4 labeling of the juxtanuclear structures is lacking, whereas the distribution of transferrin in sucrose is unaffected. Bars, 10 μm.