Cell Cycle Flashcards
DNA damage checkpoint
ATM/DNA-PK activate p53 which activates CIP1 which inhibits CDK2 cyclin E to prevent going into S phase if G1 has damage
G1 restriction point
cyclin D binds CDK4/6 and phosphorylates Rb to let E2F transcribe genes. Kip is usually inhibiting CDK 2/cyclin E and A. CDK4/6 binds p21 and p27 which inhibit aforementioned proteins. CDK2/cyclin E inhibits Kip in high enough quantities
S-phase licensing
assembles pre-replication complexes on origins between anaphase of the previous cell cycle and restriction point of current cycle
what proteins are involved in S-phase licensing
Cdc6p and cdt1 recruit Mcm proteins to make prereplicative complex
what prevents formation of extra pre-replicative complexes?
- SPF
2. geminin blocks Cdc6p/cdt1 from loading Mcm proteins
CDK1 activation
binds cyclin B, phosphorylated by CAK and inhibitory phosphorylation by Wee1
CDC25 removes inhibitory phosphorylation
G2-M transition what happens
CDK1 bound by cyclin B, cdc25 removes inhibitory phosphorylation
cdc25 and cdk1 phosphorylated to stay in nucleus and accumulate
CDK2 cyclin A condenses chromosomes and helps microtubule assembly
DNA damage detection after replication
ATM/ATR phosphorylate p53 and CHK1
CHK1 phosphorylates CDC25
CDC adaptor protein anchors it to cytoplasmic microtubules
p53 stabilizes arrest but not needed
what triggers anaphase
sudden loss of CDK1 activity bc of cyclin A destruction
APC
ubiquitin-ligase complex that targets cyclins and the cohesion complex
-degrades cyclin, degrades securin which activates separase to degrade cohesion
standard method to detect microdeletion
FISH
