Growth factor signaling is concentrated at FAs. (A–C) HeLa cells grown in full-nutrient medium were serum starved (for p-EGFR and p-IGFR1 staining) or amino acid starved (for SLC3A2 staining) and then stimulated as indicated. Cells were fixed and immunostained for p-IGFR1 (A), p-EGFR (B), or SLC3A2 (C) and paxillin, and colocalization was quantified. Error bars represent SEM; n = 3 independent experiments. Scale bars, 20 µm (insets, 10 µm). Nuclei were visualized with DAPI. ***, P < 0.001; two-sided Student’s t test.