Chapter 17: Cell cycle Flashcards
1
Q
MPF
A
- Maturation promoting factor
- made up of Cyclin B and CDK1
- induces entry into M phase
2
Q
When are cyclins degraded and where do they accumulate?
A
Cyclins accumulate in interphase and are degraded at the end of mitosis
3
Q
Wee1 function?
A
phosphorylates CDK1, inactivating MPF
4
Q
Cdc25 function?
A
phosphatase the dephosphorylates CDK1, activating MPF
5
Q
How is Cyclin B degraded?
A
After mitosis via ubiquitynilation by APC/C
6
Q
4 mechanisms that regulate CDK’s?
A
- cyclin association
- activating phosphorylation
- inhibiting phosphorylation
- CDK inhibitor association
7
Q
Cyclin D is synthesized in reponse to?
A
growth factors
8
Q
Unregulated cyclin D results in?
A
cancer
9
Q
Properties of the Rb protein?
A
- First identified in patients with retinoblastoma
- absence results in cancer
- tumor suppressor gene
- activity regulated by phosphorylation
10
Q
Effect of phosphorylation on Rb
A
- phsophorylated by CDK4,6/Cyc D
- disassociation from E2F
- activation of transcription
11
Q
CDK2/Cyclin E function in what phase?
A
entry into S phase
12
Q
p27 function?
A
inhibits CDK2/cyc E activity in G0 and ealry G1
13
Q
MCM helicase function?
A
- regulate DNA replication
- require phosphorylation to be active
- phosphorylated by DDK
14
Q
cell cycle arrest mediated by?
A
ATM and ATR
15
Q
p53 is phosphorylated by?
A
ATM and Chk2
