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Flashcards in 10_Secretory Pathway Deck (23)
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1

Which part of the Golgi complex is closest to the plasma membrane?

Trans-Golgi Network (TGN)

2

What pathway of vesicle travel do COPII, COPI and Clathrin mediate?

COPII: ER to Golgi
COPI: Golgi to ER
Clathrin: Golgi to Endosome, PM to Endosome, and perhaps some others.

3

What technique can be used to isolate different types of vesicles?

homogenization and differential centrifugation

4

Which coat protein form polyhedral structures around vesicles?

Clathrin

5

What type of microfilament to vesicles travel along in animal cells?

microtubules

6

When COPII-coated vesicles uncoat and fuse with another, what do they form?

VTC (vesicular-tubular carriers)

7

What supplies the energy for movement of VTCs along microtubules by motor proteins?

ATP

8

Which vesicular coat is the G-protein Sar1 associated with?

COPII

9

What are GEFs?

Guanine Nucleotide Exchange Factors; they activate monomeric small GTPases

10

What does exchange of GDP for GTP allow Sar1 to insert into the membrane?

the amino end is exposed in GTP, and the hydrophobic N-terminus allows Sar1 to instert into the membrane

11

Which proteins recognize Sar1/GTP and cargo vesicles, and are recruited to surround the vesicle? (discussing COPII-assembly)

Sec23/Sec24
and then Sec 13/Sec31

12

Once the coated vesicle is formed, what triggers Sar1 to hydrolyze GTP? What is the effect of this?

curvature of the membrane
coat disassembles

13

What do Rab proteins provide compartments with? Are they G-proteins?

identity, and yes

14

What is the name of the protein pair that provides specificity to vesicle fusion?

SNARES

15

What tethers the vesicle to the target membrane prior to docking and fusion?

Rab effector is the tethering protein, which recognizes the specific Rab-GTP on the vesicle and tethers it.

16

What are the v-SNARES and t-SNARES involved in a synaptic vesicle and the neuronal plasma membrane?

v-SNARE: synaptobrevin
t-SNARES: Snap25 and syntaxin

17

What is needed to unfold the SNARE complex after fusion of the vesicle?

energy (so, an ATPase)

18

On which positions of the headgroup can phosphoinositides be phosphorylated?

3, 4, 5

19

What do kinases and phosphatases do to phosphoinositide headgroups?

kinase: adds a P
phosphatase: removes a P

20

Which phosphoinositide is enriched in the plasma membrane?

PI(4,5,)P2

21

In which cellular compartment membrane is PI(4)P enriched?

Golgi complex

22

What phosphoinositide is found abundantly in endosome membranes?

PI(3)P

23

What is the GEF that allows for exchange of GDP for GTP in Sar1?

Sec12