Supplementary Fig 1 from FGFR1 Is Critical for RBL2 Loss–Driven Tumor Development and Requires PLCG1 Activation for Continued Growth of Small Cell Lung Cancer

A. Immunoblot for FGFR1, phosphorylated-FGFR1 (Tyr653/654), RBL2, phosphorylated-RBL2 (Ser672), E2F1, and E2F4 among human SCLC lines. ACTB blot verifies equal loading of total proteins. Arrows indicate specific bands. B. A hypothetical model of mechanisms regulating FGFR1 transcription. E2F1-driven FGFR1 transcription is suppressed by RBL2-E2F4 repressor complex. In the event of RBL2 loss or phosphorylation, E2F4 loses its ability to repress FGFR1, and E2F1 activates FGFR1 transcription.