Tyrosine residues 1063, 1068, 1230, 1231, and 1337 play a functional role in E-R3–dependent proliferation, migration, and survival. (A) Mitogenic response of HUVECs transduced with E-R3 mutant receptors as indicated. Quantitative analysis of [³H] incorporation of HUVECs treated with EGF. The results are expressed as the mean ± SD of 3 independent experiments. (B) Chemotactic response of HUVECs transduced with E-R3 mutants as indicated. Cells seeded in the upper well of a Boyden chamber at 37°C and the lower well contained 10 ng/mL EGF. Cells migrating through the polycarbonate filter were quantified by staining with Giemsa solution, and counting was performed in a light microscope (magnification, × 40). The results are expressed as the mean ± SD of 3 independent experiments. (C) Apoptosis of HUVECs transduced with E-R3 mutant constructs as indicated. Quantification of DNA fragmentation by TUNEL staining expressed as a percentage over total nuclei stained with DAPI of cells after 24 hours of serum starvation or in the presence of 10 ng/mL EGF. The results are expressed as the mean ± SD of 3 independent experiments.