MT2 Flashcards
ARP2/3
Nucleating factor recruited by WASP/WAVE
Kinesin-5
pushes poles apart, crosslinks MT’s, when inhibited it makes monopolar spindle
Kinesin-1
moves toward (+) ends
Kinesin-13
NON-MOTOR, induces catastrophes
Kinesin-14
moves toward (-) ends
dynein moves towards?
-
kinesin moves towards?
+
GTPcap makes MT bend? T/F
F, make straight
GDPcap makes MT bend? T/F
T, make bend
COPI goes to which end?
+
COPII goes to which end?
-
ActA function?
actin assembly! when with ARP2/3 they shorten nucleation phase (also in bacteria only)
MAP function?
regulate instability (w Tau), MAP2 induces resuces
Rapid DNA damage response
uses ATR to (P) Chk1 which (P)’s cdc25 which binds to 14-3-3 and goes to cytoplasm from nuc?
Slow DNA damage response
uses ATM to (P) Chk2 which stabilizes p53. p53 when unstable is degraded, when stable it activates p21 to repair or tells cancer to die
what inhibits p53?
MDM2
Latrunculin function?
lowers concentration of actin so nothing is polymerized
Cytochalsin function?
caps (+) ends and increases depolymerization
Phalloidin function?
decreases depolymerization
Profilin function?
increase polymerization by providing pool of actin
Thymosin function?
decreases polymerization
Cofilin function?
binds to (-) end and increases depolymerization
colchicine function?
depolymerize MT’s
taxol function?
stabilize MT by decreasing depolymerization
CDC20 function?
-targets securin to separate chromosomes, when securing is degraded, separase is inactive and stuck in metaphase
-anaphase promoting factor, if box destroyed there is arrest in metaphase
-ubiquitin ligase to sent stuff to proteasome
what inhibits CDC20?
MAD2, and it binds to empty kinetochores
CDC25
unphosphorylates T14 & T15 to step on the gas and after cyclinB was inhibited
Gelsolin function?
binds to actin and cuts in half, exposing new (+) ends
kinesin is in rigor when?
non-hydrolyzable ATP is present
γ-TuRC complex
nucleates MT’s, creates scaffolding
Myosin 1
single motor head & with membranes
MyosinV
2 heads to be able to “walk”, tails connect to Rab to allow specific cargo attachment
MyosinVI
moves toward (-) ends, has clathrin coated pit
polar ejection force
moves chromosomes away from poles (metaphase)
what moves chromosomes to metaphase plate
Chromokinesin and dynein
E2F importance
decides whether to enter cell cycle, when active induces cyclins E and A
CDC6 function?
binds in G1 to initiate replication, must be removed to synthesize
what does cyclinE need to phosphorylate to continue cycle?
helicase and CDC6
Based on the experiment above and your understanding of the cell cycle, the first 90
amino acids of cyclin are__________________
A. necessary for anaphase onset and the activation of seperase
B. sufficient for anaphase onset and the degradation of securin
C. necessary for chromosome movements and the ubiquitination of cdc20
D. necessary for chromosome movements and the ubiquitination of cdh1
E. sufficient for chromosome movements and the degradation of cyclin
A. necessary for anaphase onset and the activation of seperase
In order to understand anaphase onset more completely, you delete securin
expecting premature sister chromatid separation. However, anaphase occurs at the
proper time, not prematurely. You then do a screen for mutations that cause early sister
chromatid separation in the securin deletion mutant background. You isolate a Serine
to Alanine mutation in separase. You hypothesize that the point mutation in separase
blocked __________, which normally prevents sister chromatid separation.
A. Phosphorylation by cyclinB/CDK
B. Ubiquitination by cdc20
C. Scc1 cleavage and opening of the cohesin ring
D. Phosphorylation by wee1
E. Phosphorlyation by cdc25
A. Phosphorylation by cyclinB/CDK
Which cyclin is used to initiate DNA synthesis, and what is its target?
A. Cyclin D and its target is MCM helicase
B. Cyclin E and its target is cdc6
C. Cyclin B and its target is Rb
D. Cyclin A and its target is cdc6
E. Cyclin A and its target is Rb
B. Cyclin E and its target is cdc6
Which cyclin is used to prevent the second initiation of S-phase? What is its target?
A. Cyclin D and its target is Rb
B. Cyclin B and its target is Cyclin E
C. Cyclin A and its target is cdc6
D. Cyclin E and its target is cdc6
E. Cyclin A and its target is Rb
C. Cyclin A and its target is cdc6
hich cyclin is used to make sure the cell has grown enough before passing the
START point, and what is its target?
A. Cyclin D and its target is Rb
B. Cyclin E and its target is wee1
C. Cyclin B and its target is wee1
D. Cyclin A and its target is cdc25
E. Cyclin D and its target is wee1
A. Cyclin D and its target is Rb
Which cyclin is used to initiate anaphase onset, and what is its target to initiate
anaphase onset?
A. Cyclin B and its target is seperase
B. Cyclin B and its target is cdc20
C. Cyclin B and its target is securin
D. Cyclin D and its target is securin
E. Cyclin D and its target is seperase
B. Cyclin B and its target is cdc20
hen the rapid DNA damage checkpoint is activated in G2, which of the following
occurs?
A. All DNA is replicated
B. Cdc25 is active
C. Cdc25 is in the cytoplasm
D. Chk1 is in the non phosphorylated form
E. Wee1 activity is activated by chk1
C. Cdc25 is in the cytoplasm
cdc20 plays a central role in progression through the cell cycle. Different proteins
have different effects on cdc20. Which of the following statements best describes
cdc20?
A. cdc20 is a kinase that is inhibited by the chk1 kinase and stimulated by CDK.
B. cdc20 is an ubiquitin ligase that is activated by CDK and inhibited by Mad2.
C. cdc20 is an ubiquitin ligase that is phosphorylated by cdc25 and inhibited by DNA
damage.
D. cdc20 is a phosphatase that removes the phosphate on Thr 161 of CDK that was
placed there by wee1 kinase.
E. cdc20 is a phosphatase that is inhibited by DNA damage and activated by CDK
B. cdc20 is an ubiquitin ligase that is activated by CDK and inhibited by Mad2.
which of the following mutations would cause a metaphase arrest?
A. A null mutation in Securin
B. A Ser to Ala mutation in Securin
C. A Lys to Ala mutation in Securin
D. A Ser to Ala mutation in Seperase
E. A Lys to Ala mutation in cdc20
C. A Lys to Ala mutation in Securin
MDM2 normally directly inhibits p53 activity by destabilizing p53. You would
therefore predict that MDM2 has which of the following properties?
A. MDM2 is a proto-oncogene
B. MDM2 is a tumor suppressor gene
C. MDM2 activity increase apoptosis
D. MDM2 activity slows down the cell cycle
E. MDM2 activity increases p21 and p27
A. MDM2 is a proto-oncogene
how does actin move cells? all steps
- signal
- signal activates WASP or WAVE to recruit ARP2/3 to rapidly grow actin filaments
- profilin aids growth by supplying actin
- new filaments grow off old ones to form a block and push cell to move
- CapZ binds to ends on lagging side to not waste energy
- older filaments are depolymerized by cofilin
