Figure 9.

Surface immunogold labeling with anti-EGFR mAb of B82 cells expressing EGFR WT (a–c) or EGFRΔAP-2 mutant (d). After incubation with EGF for 1 h at 4°C (a), EGFRs are distributed over the cell plasma membranes, preferentially associated with the microvilli, and excluded by clathrin-coated pits (a, arrowhead). After warming to 37°C for 5 min, either WT EGFRs (b and c) or mutant EGFRs (d) appear clustered over the nonvillous portions of the plasma membrane (b) and inside clathrin-coated pits (c and d, arrowheads). Bars, 0.5 μm.