Neoplasia 2: Cyclins and Cyclin-Dependent Kinase (Oncogenic Activation)

Question 1

CDK4, Cyclin D

Answer 1

Complex that phosphorylates Rb, allowing to progress the G1 restriction point.

Rb: G1-S

Question 2

Cell Cycle Inhibitors: CIP/KIP Family

Answer 2

Block the cell cycle by binding to cyclin-CDK complexes

Question 3

Cell Cycle Inhibitors: CIP/KIP Family - p21

Answer 3

Induced by tumor supressor p53

Question 4

Cell Cycle Inhibitors: CIP/KIP Family - p27

Answer 4

Responds to growth suppressors such as TGF-beta (which can inhibit most cells n body)

Question 5

Cell Cycle Inhibitors: INK4/ARF Family - p16/INK4a

Answer 5

Binds to Cyclin D-CDK4 and PROMOTES inhibitory effects of Rb

Question 6

Cell Cycle Inhibitors: INK4/ARF Family - p14/ARF

Answer 6

Increases p53 levels by inhibiting MDM2 activity

MDM2, when not inhibited, normally inhibits p53

Question 7

Cell Cycle Checkpoints: Rb

Answer 7

Tumor supressor

Binds to E2f in HYPOphosphorylated state, preventing G1/S transition

Question 8

Cell Cycle Checkpoints: p53

Answer 8

Tumor supressor
Causes apoptosis by inducing BAX
G1/S and G2/M (mainly)

Question 9

What inhibits Cyclin D/CDK4?

Answer 9

p16/INK4

p21 (influenced by p53)

Question 10

What inhibits Cyclin E/CDK2?

Answer 10

p27 (influenced by TGF-B)