Cell Cycle Flashcards
What are the 4 cell cycles ?
what is interphase?
G1 S (dna rep) G2 M
G1 S G2=interphase
What is the checkpoint between g1 and S? what conditions need to exist to get past it?
R(estriction checkpoint), growth conditions
g2/M checkpoint conditions?
Has all dna been replicated so can enter mitosis?
M to anaphase checkpoint..?
are all spindles attached?
CDK need what to be active?
cyclins
What are the 4 different cyclins? what phases or checkpoints do they apply to?
CDK4,6 cyclin D -R checkpoint/enough growth
CDK2, cyclin E- G1/S: DNA replication
cyclin A-
cdk 1 cyclin B-g2/M Mitosis checkpoint
How does p53 inhibit cell growth?
when phosphorylated p53 acts as a TF for p21 (CDK inhibitor)
wee1 kinase phosphorylates CDK1 to…
inhbit g2/M progression…not enough genetic material! phosphatase removes inhibition
Name a few growth factors that induce cyclin D or progression through R checkpoint?
APC (adenoma polypus..) usually inhibits Wnt, but when mutated WNT stimulates cyclin D.
-EGF, Ras and others also stimulate
how does D turn on E?
D phosphorylates Rb>e2f released> E=dna replication
What does E + cdk4 degrade that coincides w start of S phase?
the prereplicative complex (which lives in future origins of replication)
where are UBQ tagged cyclins (other proteins) degraded ?
proteasome
What are the two functions of APC?
- which cyclin
- what does APC stand for?
anaphase promoting complex.
- degrades cyclin B (m phase progression)
- activates separase to separate chromosomes (seg of chroms)
Whats the SCF complex?
UBQ complex that has an F box that binds to phosphorylated (by cdk) proteins
