Retinoblastoma protein binds the transcription factor E2F. What does that binding stop?

1. E2F is a transcription factor, so its job is to switch specific genes on. 2. The genes it switches on encode the proteins needed to move from G1 into S. 3. Active Rb binds E2F and holds it, so those genes stay off. 4. With the transition proteins missing, the cell cannot enter S phase. 5. As the cell grows, Rb is slowly phosphorylated until it lets go of E2F. 6. The freed E2F then switches the genes on and the block is lifted. 7. DNA repair is triggered by p53, not by the Rb and E2F pair. 8. Spindle proteins are needed later, at the G2 to M step, not at the G1 to S step. _Source: OpenStax Biology 1e (CC BY 4.0), Chs 10 and 11, section 10.3 Control of the Cell Cycle_