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Figure 4 | Molecular Cancer

Figure 4

From: Evidence for efficient phosphorylation of EGFR and rapid endocytosis of phosphorylated EGFR via the early/late endocytic pathway in a gefitinib-sensitive non-small cell lung cancer cell line

Figure 4

Evidence for an efficient phosphorylation of EGFR and rapid delivery of pEGFR into the early endosomes after EGF stimulation in PC9 cells. The PC9 (A) or QG56 (B) cells stimulated with EGF for 15 min on ice were further incubated at 37°C with Texas red-transferrin (red) for 3, 6, or 15 min, and cells were fixed and double-stained for pEGFR (green) as described in the Materials section. Superimposed images of pEGFR and Texas red-transferrin are shown. Each cell line was stained with DAPI (blue) to reveal nuclei. The white arrows indicate the colocalized early endosomal vesicular structures positive for pEGFR and Texas red-transferrin. The merged confocal images as yellow color as indicated by white arrows (a, d) at 3 min incubation were quantified and presented as the percentage of total amounts of pEGFR-positive vesicles per cell in D. In PC9 cells (A), ligand-induced EGFR phosphorylation occurs efficiently in early endosomes or in plasma membrane (a, b, c). By contrast, only small fraction of pEGFR staining associated with early endosomal vesicles is seen in the cytoplasm of QG56 cells even after 15 min incubation (f).

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Molecular Cancer

ISSN: 1476-4598