Figure 5.

Endocytosis of HRP and EGF require an intact cytoplasmic domain of the EGFR. Cells expressing either EGFR:WT, EGFR:c'973, EGFR:c'991, or EGFR:c'1000 were transfected with virus alone or virus encoding Rab5. After transient transfection, the amount of HRP (A) or ¹²⁵I-EGF (B) internalized at 37°C was quantified as described in Materials and Methods (mean ± SD, n = 4). (C and D) Cells were transfected with virus alone, or virus encoding Rab5, or Rab5:N34 and the internalization of either HRP (C) or ¹²⁵I-Tf (D) was carried out for 10 min at 37°C in the presence or absence of 6 μg/ml transferrin. Mean ± SD, n = 3.