Definitions

Question 1

Define tumour suppressor gene

Answer 1

A gene which protects a cell against progressing a step towards cancer. Its presence is protective and its absence can allow cancer

Question 2

Define oncogene

Answer 2

A gene which promotes uncontrolled cell division

Question 3

Define proto-oncogene

Answer 3

A gene which, if mutated, becomes an oncogene

Question 4

At what position does PDK1 phosphorylate Akt?

Answer 4

Threonine 308

Question 5

At what position does mTORC1 phosphorylate Akt?

Answer 5

Serine 473

Question 6

What does PI3K do?

Answer 6

Phosphorylates PIP2, PIP and PI at positions 3, 4, and 5.

Question 7

What does SHIP1 do?

Answer 7

Phosphatase at position 5 of PIP3

Question 8

What does PTEN do?

Answer 8

Phosphatase of PIP3

Question 9

Why are PTEN and SHIP1 mutations associated with cancer?

Answer 9

If mutated to lose function, can no longer antagonise the effect of PI3K and so the production of PIP3. More PIP3 means more scaffolds for Akt phosphorylation and so, more of the resulting downstream growth promoting signals.