Question

Which of the following about Rb tumor suppressor protein is correct?

(a) It binds E2F transcription factor and prevents cell from entering S phase until a mitogenic signal is received

(b) It is activated when phosphorylated by Cdk

(c) It is a transcription factor

(d) When a mitogenic signal is received, it binds the transcription factor E2F and thus stimulates the cell to enter S phase

This question was addressed to me in examination.

Origin of the question is Oncogenes, Tumor Suppressor Genes and Programmed Cell Death in division Biosignalling of Biochemistry

Answer 1

Right option is (a) It binds E2F transcription factor and prevents cell from entering S phase until a mitogenic signal is received

To explain I would say: Rb protein binds E2F transcription factor and prevents cell from entering S phase until a mitogenic signal is received.