1 - Oncoproteins and tumour suppressors in the cell cycle

Question 1

Li-Fraumeni Syndrome:

Answer 1

This syndrome is caused by a germline mutation in TP53 which is characterised by early onset of cancers of diverse types.

Question 2

MDM2:

Answer 2

Regulator of p53 protein levels. It is an E3 ligase which attaches ubiquitin to p53 and results in its degradation.

Question 3

P53:

Answer 3

This tumour suppressor is lost in many cancers and is a transcription factor which regulates the transcription of proteins which halt the cell cycle, initiate apoptosis, mediate DNA repair or inhibit angiogenesis and the EMT.

Question 4

RB:

Answer 4

Retinoblastoma protein- tumour suppressor nuclear phosphoprotein which regulates the G1 phase of the cell cycle. It binds to and inhibits the transcription factor E2F.

Question 5

Tetramer:

Answer 5

Protein composed of 4 monomers