Vesicular Traficking III (Lecture 16)

Question 1

The ______-Golgi network sorts proteins into vesicles targeted for different destinations

Answer 1

trans

Question 2

True or False: Regulated secretory proteins are concentrated and stored until secretion is signaled; constitutively secreted proteins are continuously delivered to the plasma membrane

Answer 2

True

Question 3

What are the 5 destinations from the trans-Golgi network.

Answer 3

1.  COPI vesicle 
         Retrograde 
2.  AP3 complex vesicles —        
       may not have clathrin 
3.  Clathrin-coated vesicles
4.  Constitutive secretory vesicles
5.  Regulated secretory vesicles

Question 4

What is the outer form structure of clathrin coats?

Answer 4

Triskelion

Question 5

The inner layer of clathrin coated proteins are composed of _______.

Answer 5

Adapter protein complexes

Question 6

True or False: Each adapter protein complex determines which cargo proteins are in a vesicle by binding to cytosolic domains of membrane protein.

Answer 6

True

Question 7

Other then the AP complex, what is another type of adapter protein that is a single large polypeptide and also binds to clathrin and cargo elements.

Answer 7

GGA

Question 8

______ is known in anterograde or early stages of secretion where as ______ is known in later stages of secretion.

Answer 8

COPII, COPI and Clathrin

Question 9

For COPI what is the mode of transport, luminal sorting signal, cytoplasmic sorting signal and GTPase for coat assembly/disassembly?

Answer 9

Retrograde transport

KDEL

KKXX and di-arginine

ARF protein

Question 10

For AP3 complex vesicles what is the mode of transport to, coat protein and GTPase for coat assembly/disassembly?

Answer 10

directly to lysosome

does have clathrin binding site but does not have to use it

ARF protein

Question 11

______ vesicles that bud from trans-Golgi network en route to the late endosome (eventually to lysosome)

Answer 11

AP1

Question 12

What is the sorting signal for AP1 vesicles?

Answer 12

Recognize YXXΦsorting signal — 

Y = Tyr, X = any amino acid, Φ = a bulky, hydrophobic amino acid

Question 13

______ vesicles that bud from plasma membrane during endocytosis

Answer 13

AP2

Question 14

True or False: AP2 vesicles also recognize YXXΦsorting signal.

Answer 14

True

Question 15

______ are also vesicles that bud from trans-Golgi network en route to the late endosome.

Answer 15

GGA

Question 16

What is the sorting signal for GGA vesicles.

Answer 16

Recognize Asp-X-Leu-Leu and Asp-Phe-Gly-XΦsequences

Question 17

What are the three types of clathrin coated vesicles.

Answer 17

AP1, AP2, GGA

Question 18

______ pinches off Clathrin-coated vesicles.

Answer 18

Dynamin

Question 19

True or False: Dynamin is dependent on ATP.

Answer 19

False, dependent on GTP

Question 20

True or False: Dynamin polymerizes around the neck of the bud and then hydrolyzes GTP and the conformational change in dynamin stretches the neck until vesicle is pinched off

Answer 20

True

Question 21

Cytosolic ______ hydrolyzes ATP to depolymerize clathrin into triskelions of clathrin-coated vesicles.

Answer 21

Hsp70

Question 22

______ vesicles transport constitutively secreted proteins and plasma membrane proteins to the plasma membrane such as ECM proteins, blood proteins, immunoglobulins.

Answer 22

Constitutive secretory

Question 23

______ vesicles store and process secreted proteins until signaled to fuse with the plasma membrane to secrete the proteins such as digestive enzymes and peptide hormones.

Answer 23

Regulated secretory

Question 24

True or False: Regulated and Constitutive secretory vesicles have coat proteins that are still unknown.

Answer 24

True

Question 25

In polarized epithelial cells, the ______ domain is abuts adjacent cells and the underlyingbasal lamina and the ______ domain is exposed to the exterior of the body or to an internal open space (e.g., intestinal lumen, duct) .

Answer 25

Basolateral, Apical

Question 26

What prevents movement between the apical and basolateral membranes?

Answer 26

Tight junctions

Question 27

How are apical and basolateral bound membrane proteins sorted?

Answer 27

sorted into their own transport vesicles with unique v-SNAREs and Rab proteins targeting either the apical or basolateral region

Question 28

Influenza viruses bud from only the ______ membrane and VSV viruses bud from only the ______ membrane.

Answer 28

Apical, basolateral

Question 29

What are the two types of motifs associated with apical and basolateral bound membrane proteins?

Answer 29

Tyrosine-based, di-leucine-based

Help membrane proteins associate with clathrin adapter proteins

Question 30

True or False: Proteins targeted to the apical membrane of epithelial cells often have a glycosylphosphatidylionositol (GPI) membrane anchor.

Answer 30

True

Question 31

What happens endocytosis takes in both basolateral and apical proteins?

Answer 31

Basolateral proteins sorted back to basolateral membrane — 

Apical proteins move in vesicles across the cell and fuse with apical membrane (Transcytosis)

Question 32

______ is used to visualize protein size and abundance.

Answer 32

SDS-PAGE

Question 33

What type of stain is reversible?

Answer 33

Ponceau Red

Question 34

What type of stain is irreversible and insensitive?

Answer 34

Coomassie Blue

Question 35

What type of stain is complex and sensitive?

Answer 35

Silver Staining