The normal function of the tumor suppressor protein Rb is to

Question

Quizplus · Accepted Answer

The normal function of the tumor suppressor protein Rb is to inhibit progression through the G1/S restriction point, also called the "start checkpoint." This point ensures that the cell has sufficient nutrients and energy to proceed through the cell cycle. Rb works by binding to E2F transcription factors and preventing them from activating genes involved in cell division. When Rb is phosphorylated, it releases E2F and allows for progression through the restriction point. Mutations or loss of Rb function can lead to uncontrolled cell division and tumor formation. Choices A, B, and D are not correct because Rb's role is not primarily related to inducing apoptosis, inhibiting Ras, or inhibiting Cdk4/cyclin B activity.

The Normal Function of the Tumor Suppressor Protein Rb Is