Liu 2 Vesicular Transport

Question 0

COP 2: from ____ to ____

Answer 0

ER to golgi.

Question 1

COP1: From ____ to ____

Answer 1

Cis golgi to ER.

Question 2

Where is clathrin used?

Answer 2

PM, trans Golgi.

Question 3

What do adaptins do?

Answer 3

Link clathrin with transmembrane cargo receptors.

Question 4

What does dynamin do?

Answer 4

dynamin G protein pinches off the clathrin coated vesicle from PM.

Question 5

T or F. the clathrin coat stays associated with the vesicle after pinching off.

Answer 5

False. the clathrin coat dissociates soon after vesicle formation.

Question 6

COP 1 will only bind to target membrane once it has been primed by ____.

Answer 6

GTP-Arf

The first cop gets bit by an Arf-ing dog, goes to the ER.

Question 7

COPII will only associate with target membrane after membrane is primed by _____

Answer 7

GTP Sar1.

Question 8

GTP to GDP ARF/Sar1 will cause the coatomer around a vesicle to ____.

Answer 8

disassemble.

Question 9

What is required on the vesicle and target membrane for vesicle targeting specificity, and fusion.

Answer 9

V snare, T snare,
Rab locks interaction by hydrolyzes bound GTP
NSF induces fuse, also dissociates V and T snares for later use

Question 10

The COP II vesicles form vesicular tubular clusters, and these clusters move along ____ to the golgi.

Answer 10

microtubules.

Question 11

How does ER retrieve escaped ER proteins from the Golgi? What is the name of the signal on ER proteins?

Answer 11

ER proteins have a KDEL sequence. KDEL receptors are in both ER and Golgi, but KDEL binds to KDEL receptors only in Golgi (more acidic, pH dependent binding). COP1 then brings bound KDEL receptors back to ER.

Question 12

Which use clathrin?
Constitutive pathway from the trans Golgi.
Regulated secretory pathway from trans Golgi.

Answer 12

Regulated.

Question 13

What is the V snare and T snare and Rab called in synaptic vesicles?

Answer 13

V snare synaptobrevin
T snare syntaxin
Rab = Rab 3

Question 14

How is LDL taken into cells?

Answer 14

Via LDL receptors, which are mainly found in clathrin coated pits.

Question 15

Is LDL receptor pinocytosis dependent on LDL receptors binding to LDL?

Answer 15

No. It’ll uptake the empty LDL receptor too

Question 16

A mutation in the C terminal end of LDL receptors may cause a patient to have _____.

Answer 16

Familial hypercholesterolemia, since adaptin/clathrin can’t bind LDL receptors, LDL receptors thus don’t congregate in coated pits.

Question 17

The low pH in the late endosome causes the iron in _______ to be released into the cell.

Answer 17

transferrin.

Question 18

________ binds to transferrin receptor at neutral pH. ______ unbinds transferrin receptor at neutral pH.

Answer 18

Ferrotransferrin

Apotransferrin

Question 19

Baby’s obtain _____ from their mother’s milk via pH dependent interactions from the newborn gut (6pH) to newborn extracellular fluid (7pH)

Answer 19

IgGs.

Question 20

EGF receptors epidermal growth factor is preclustered in coated pits, like LDL receptors are.

Answer 20

False. EGF receptors only cluster after EGF binds.

Question 21

How is EGF receptor “down regulated?”

Answer 21

EGF and EGF receptors are internalized by clathrin coated pits, and everything is degraded by lysozymes.

Question 22

The proteins in the internal vesicles of multivesicular bodies of late endosomes are marked with

Answer 22

ubiquitin.

Question 23

Maturation of early endosomes to late endosomes are marked with the making of

Answer 23

multivesicular bodies.

Question 24

T or F. both the early and late endosome continually recycle vesicles to the Golgi.

Answer 24

False, only early endosomes do this.

Question 25

What is autophagy and when does it occur?

Answer 25

fusion of lysosomes with unwanted organelles, or for nutrients when cell is starved.

Question 26

What is the marker on lysosomal enzymes that bring the enzyme to lysosomes?

Answer 26

mannose 6 phosphate

Question 27

How is M6P added to a lysosomal hydrolase? Start with lysosomal hydrolase, N linked with mannose.

Answer 27

hydrolase binds with UDP GlcNac PP via GlcNac phosphotransferase
UDP transfers GlcNac P to hydrolase. Thus mannose gets phosphorylated.

Question 28

M6P receptors are concentrated in

Answer 28

clathrin coated vesicles

Question 29

How is it ensured that the hydrolase does not return with the M6P receptor when receptor is recycled from the lysosome?

Answer 29

phosphate removed from mannose, thus M6P receptor can’t bind and bring it back to TGN.

Question 30

What is I cell disease?

Answer 30

pts lack GlcNac phosphotransferase. lysosome enzymes dont have P on mannose, no binding to M6P. no hydrolases in lysosomes, buildup of shit.