Lecture 3-4 extra

Question 1

How does CDC25 dephosphorylates ?

Answer 1

CDC25 dephosphorylates CDK1/cyclin B facilitating its activation at G2/M

Question 2

What does CDC25 isoform

Answer 2

CDC25 isoforms CDC25A, B and C in humans

Question 3

Are CDC25 overexpressed in cancers

Answer 3

Yes

Question 4

What does CDC25 phosphatases act on

Answer 4

acts upon tyrosine and threonine residues

Question 5

What are CDC25 inactivated by

Answer 5

CDC25 are inactivated by Chk (Checkpoint) kinases as a result of DNA damage

Question 6

What does p21 inhibit

Answer 6

The Cyclin-dependent kinase inhibitor p21 Inhibits CDK1-CyclinB and CDK2-CyclinE

Question 7

What tumor suppressor increased expression of p21 in response to DNA damage

Answer 7

Tumour suppressor p53

Question 8

Does TGFb increases p21 expression

Answer 8

Yes

Question 9

What can inhibit the expression of CDKI members

Answer 9

Oncogenic MYC can inhibit the expression of CDKI members

Question 10

Is p16 a Tumour suppressor gene

Answer 10

Yes

Question 11

Is p15 expression induced by TGFb

Answer 11

Yes

Question 12

When is pRb mostly unphosphorylated

Answer 12

pRb is mostly unphosphorylated during the G0 phase of the cell cycle

Question 13

When is pRb functionally inactive

Answer 13

pRb is functionally inactive when it is hyperphosphorylated

Question 14

When is pRb functionally inactived

Answer 14

pRb is functionally inactivated at the R point

Question 15

What is pRb phosphorylation initiated

Answer 15

pRb phosphorylation is initiated by D-type cyclins and CDK4/6