Seminar 4 - Cell cycle

Question 1

What type of kinases are CDKs?

Answer 1

Serine-threonine kinases

Question 2

Where do CDKs phosphorylate their substrates?

Answer 2

At Ser/Thr-Pro-X-Lys/ARG motifs

Question 3

How does the activity of CDK oscillate during the cell cycle?

Answer 3

Due to cyclin levels rising and falling

Question 4

What do the S phase genes code for?

Answer 4

1. DNA synthesis
2. DNA replication
3. DNA repair
4. Cyclin E
5. Cyclin A

Question 5

How does HPV inactivate RB?

Answer 5

HPV produces E7 proteins which bind and inactivate RB

Question 6

What factors positively regulate cyclin D/CDK4-6?

Answer 6

1. Growth factor
2. MAPK
3. Myc oncogene
4. PI3K/AKT
5. Etc..

Question 7

What are the negative regulators of Cyclin E/CDK-2?

Answer 7

CDK-interacting proteins/kinase inhibitor proteins:
p21 - CIP1
p27 - KIP1
p57 - KIP2

Question 8

What are the targets of E2F?

Answer 8

Cyclin A/B and CDK 1

Question 9

Outline the functions of CDK that are not related to the cell cycle.

Answer 9

1. CDK 3
2. CDK5: regulation of neuronal function
3. CDK7: regulation of RNA Pol II - initiation
4. CDK8: regulation of gene expression
5. CDK9: regulation of RNA Pol II - elongation
6. CDK11: regulation of gene splicing

Question 10

State examples of broad-spectrum inhibitors that can be used to target CDK enzymes.

Answer 10

1. Flavopiridol

2. Roscovitine

Question 11

State examples of selective CDK4/6 inhibitors.

Answer 11

1. PD-0332991: Palbociclib

2. LEE011: Ribociclib