Intracellular Vesicular Traffic 1

Question 1

vesicular transport mediates a continuous _______ of components between various membrane enclosed compartments

Answer 1

exchange

Question 2

What gives each compartment its full molecular address?

Answer 2

combination of markers

Question 3

________ pathways return molecules to source

Answer 3

retrieval

Question 4

Cells _______ proteins into membrane domains by assembling a special ______ on cytosolic side of the membrane

Answer 4

segregate; coat

Question 5

What are the two major functions of coats?

Answer 5

concentrates select proteins in a specialized path for transport
models the vesicle to form a basket like lattice that deforms the membrane and gives shape to the vesicle

Question 6

What are the types of coated vesicles?

Answer 6

COPI
COPII
Clathrin

Question 7

COPI mediates transport from ______

Answer 7

golgi cisternae

Question 8

COPII mediate transport from ______

Answer 8

ER

Question 9

Clathrin coasted vesicles mediate transport from ______ and ______

Answer 9

Golgi apparatus

plasma membrane

Question 10

Each clathrin subunit has how many polypeptide chains? and what does it form?

Answer 10

3 large and 3 small chains

form three leg structure called triskelion

Question 11

Triskelions assemble into a __________ structure of hexagons and pentagons that form coated pits on the ______ side of membrane

Answer 11

basket like

cytosolic

Question 12

What forms a second layer between the cage and the membrane in clarthrin coated vesicles?

Answer 12

adaptor proteins

Question 13

assembly of the coat protein molecules introduces a ______ in the membrane

Answer 13

curvature

Question 14

After the curvature forms in the membrane, what happens?

Answer 14

formation of coated buds

Question 15

______ proteins bin clathrin and membrane bound cargo receptors

Answer 15

adaptor

Question 16

After vesicle formation is complete, what happens to the clathrin coat?

Answer 16

it is lost

Question 17

What does phosphoinositides do?

Answer 17

play a major role in coat assembly, vesicle formation and protein trafficking

Question 18

Where do phosphoinositides undergo phosphorylation and dephosphorylation? and what does it form?

Answer 18

at the 3’, 4’ and 5’ positions

forms various derivatives

Question 19

Interconversion between various phosphoinositides is highly compartmentalized, _______ specific and ______ specific

Answer 19

organelle

domain

Question 20

Different organelles have unique sets of ________ and ______ to facilitate inter conversion

Answer 20

PI kinases

phosphatases

Question 21

When removing the clathrin coat, what protein assembly around the clathrin bud?

Answer 21

dynamin

Question 22

What domains does dynamic contain?

Answer 22

PIP2 binding domain

GTPase binding domain

Question 23

What does the PIP2 binding domain do?

Answer 23

tethers the protein to membrane

Question 24

What does the GTPase binding domain do?

Answer 24

regulates rate of vesicle pinching

Question 25

What does pinching do?

Answer 25

brings the 2 cytosolic sides of the membrane together and allows them to fuse

Question 26

What protein uses ATP to peel off the clathrin coat?

Answer 26

HSP 70

Question 27

What do Rab proteins do?

Answer 27

direct vesicle to specific spots on target membrane

Question 28

What do SNARE proteins do?

Answer 28

mediate fusion of vesicle with membrane

Question 29

What are Rab proteins actively regulated by?

Answer 29

GTPases

Question 30

Each Rab is ______ with one or more membrane compartments of the secretory or endocytic pathway

Answer 30

marker

Question 31

Rab is inactive in what form? active?

Answer 31

inactive: GDP bound active: GTP bound

Question 32

What happens when bound to Rab-GDP dissociation inhibitor?

Answer 32

keeps inactive GDP bound form, form is soluble

Question 33

Where is Rab1 located?

Answer 33

ER and golgi complex

Question 34

Where is Rab3A located?

Answer 34

synaptic vesicles, secretory vesicles

Question 35

Where is Rab5 located?

Answer 35

early endosomes, plasma membrane, clathrin coated vesicles

Question 36

What do SNARE proteins do?

Answer 36

catalyze fusion of vesicles with membranes

Question 37

How many different SNAREs are there?

Answer 37

35

Question 38

where are v-SNAREs found?

Answer 38

vesicle membrane

Question 39

Where are t-SNAREs found?

Answer 39

target membranes

Question 40

When v and t SNAREs interact, what happens?

Answer 40

wrap around each other to form a bundle

Question 41

Newly synthesized proteins are packaged into ________ coated transport vesicles.

Answer 41

COPII

Question 42

How does quality control occur in transport from ER?

Answer 42

incomplete/misfolded proteins are contained in the ER by binding to chaperone proteins such as BiP and calnexin, then proteins degrade

Question 43

What is homotypic fusion?

Answer 43

fusion of vesicles from same compartment

Question 44

What is heterotypic fusion?

Answer 44

fusion of vesicles from different compartment

Question 45

What are fused structures called?

Answer 45

vesicular tubular clusters

Question 46

What are the 2 faces of the golgi?

Answer 46

cis (or entry) and trans (or exit)

Question 47

What is the Cis golgi network (CGN)?

Answer 47

network of fused vesicular tubular clusters arriving from ER. Proteins and lipids enter golgi via CGN

Question 48

What is the trans golgi network (TGN)?

Answer 48

region that allows exit of proteins and lipids to next step fo secretory pathway

Question 49

Golgi plays important role in protein______

Answer 49

glycosylation