Intracellular Vesicular Traffic 1

Question 0

Vesicles ________ from primary compartment and _____ with the next one

Answer 0

Bud off

fuse

Question 1

Proteins and other biomolecules are transported via what?

Answer 1

Transport vesicles

Question 2

Transport vesicles come in different ______ and ______:

Answer 2

Shapes and sizes

Small spherical or large irregular or tubular

Question 3

Contents of vesicle called _____

Answer 3

cargo

Question 4

Transport is ______

Answer 4

directional

Question 5

___________ mediates a continuous _________ of components between various membrane enclosed compartments

Answer 5

Vesicular transport

exchange

Question 6

_______ of the _______ and ______ on membrane surface provide cues for incoming traffic

Answer 6

components
membrane
molecular markers

Question 7

______________ gives each compartment its full molecular address

Answer 7

Combination of markers

Question 8

___________ return molecules to source

Answer 8

retrieval pathways

Question 9

Cells ____ ____ into membrane domains by assembling a special ____ on cytosolic side of the membrane.

Answer 9

segregate proteins

coat

Question 10

Transport vesicles bud off as _____ ______.

Answer 10

Coated vesicles

Question 11

The coat performs 2 major functions:

Answer 11

1. concentrates select proteins in a specialized patch for transport
2. Coat molds the vesicle to form a basketlike lattice that deforms the membrane and give shape to the vesicle

Question 12

Coat ________ before vesicle fuses with target membrane

Answer 12

discarded

Question 13

____ and _____ mediate transport from ER to Golgi ______

Answer 13

COPI and COPII

Cisternae

Question 14

________-________ vesicles mediate transport from Golgi apparatus and from plasma membrane

Answer 14

Clathrin-coated

Question 15

COPI are coated vesicles of _____

Answer 15

Golgi

Question 16

COPII are coated vesicles of ______.

Answer 16

ER

Question 17

The major protein of clathrin-coated vesicles is _____.

Answer 17

clathrin

Question 18

Each clathrin subunit is made of ______ and _____ polypeptide chains that form a 3-legged structure called ________

Answer 18

3 large
3 small
triskelion

Question 19

triskelions assemble into a ___-____ structure of hexagons and pentagons that form coated pits on the _______ side of membrane

Answer 19

basket-like

cytosolic

Question 20

______ ______ form a second layer between the cage and membrane

Answer 20

adaptor proteins

Question 21

Adaptor proteins trap various transmembrane proteins including receptors that capture ____ _____ inside vesicle.

Answer 21

soluble cargo

Question 22

Assembly of the coat protein molecules introduces a _____ in the membrane.

Answer 22

curvature

Question 23

Curvature in the membrane leads too the formation of ____ ____.

Answer 23

coated buds

Question 24

____ _____ bind clathrin and membrane-bound cargo receptors

Answer 24

Adaptor proteins

Question 25

______ recruitment of membrane and cargo molecules in vesicle

Answer 25

selective

Question 26

Clathrin ___ ___ after vesicle formation completed

Answer 26

coat lost

Question 27

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

Answer 27

phosphoinositides (PI)

Question 28

Phosphoinositides can undergo rapid cycles of ______ and ______ at the __,__, and__ positions to form various derivatives

Answer 28

phosphorylation dephosphorylation 3', 4', and 5'

Question 29

_______ between various phosphinositides is highly compartmentalized. It is ____ specific and ____ specific.

Answer 29

Interconversion Organelle domain

Question 30

Different organelles have a unique set of __ ____ and _______ to facilitate the inter-conversions

Answer 30

PI kinases and phosphatases

Question 31

Different proteins bind with high specificity to the ______ of particular phosphoinositidies.

Answer 31

Headgroups

Question 32

The headgroups of PI control ____ and ____ of____ to specific organelles/domains and regulate vesicle trafficking.

Answer 32

recruitment and binding of proteins

Question 33

What are membrane bending proteins?

Answer 33

BAR domains

Question 34

A protein called ______ assembles a ring around a clathrin bud

Answer 34

dynamin

Question 35

Dynamin contains a ___ ____ _____ (tethers the protein to membrane) and a _____ ______ (regulates rate of vesicle pinching)

Answer 35

PIP2 binding domain | GTPase domain

Question 36

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

Answer 36

pinching

Question 37

Dynamin recruits other proteins that _____ the____ _____ e.g., by lipid modifying enzymes that change lipid composition

Answer 37

distort the lipid bilayer

Question 38

Vesicle looses coat, ______ is degraded which weakens the binding of adaptor proteins.

Answer 38

PIP2

Question 39

____ ___ chaperone protein uses ATP to peel off the coat.

Answer 39

Hsp 70

Question 40

Specificity in targeting is achieved by ____ _____ on vesicles and ______ ______ on target membrane.

Answer 40

surface markers | complementary receptors

Question 41

Two types of proteins play an important role in vesicle targeting:

Answer 41

Rab and SNARE

Question 42

___ _____ direct vesicle to specific spots on target membrane

Answer 42

Rab proteins

Question 43

_____ ______ mediate fusion of vesicle with membrane

Answer 43

SNARE proteins

Question 44

____ _____ play a central role in specificity of vesicular transport

Answer 44

Rab protein

Question 45

Rabs are _____ ______ (~60)

Answer 45

monomeric GTPases

Question 46

Activity of Rab is regulated by ___ _____.

Answer 46

GTP hydrolysis

Question 47

Each Rab is associated with one or more membrane compartments of the ____ or _____ pathway.

Answer 47

Secretory | endocytic

Question 48

Rab serves as a ____ for that compartment.

Answer 48

Marker

Question 49

Rab cyles between ____ and _____ and regulates _______ assembly of complexes on membrane

Answer 49

cytosol membrane reversible

Question 50

Rab is ____ in GDP-bound form and _____ in GTP bound form

Answer 50

Inactive, active

Question 51

Binding to ____-____ _____ _____ keeps it in the inactive GDP-bound form. This form is _____.

Answer 51

Rab-GDP dissociation inhibitor (GDI) | soluble

Question 52

interactions with ____-_____ keeps it in an active GTP bound form. This form is _____ bound to a membrane.

Answer 52

Rab-GEFs | Tightly

Question 53

Active form of Rab binds to __ ____ (motor proteins or tethering proteins) present on the target membrane.

Answer 53

Rab effectors

Question 54

Rab and Rab effectors facilitates membrane _____ and _____.

Answer 54

Tethering and fusion

Question 55

SNARE proteins catalyze _____ of ______ with membranes

Answer 55

fusion of vesicles

Question 56

____ different SNAREs each associated with a particular compartment

Answer 56

35

Question 57

SNARE exist as complementary sets:

Answer 57

v-SNAREs (single polypeptide) found on vesicle membrane | t-SNAREs (2-3 proteins) found on target membranes

Question 58

Interaction between __ and ___ forms allow them (SNAREs) to wrap around each other to form a bundle.

Answer 58

v and t

Question 59

Resulting SNARE complexes ____ the 2 _______ together.

Answer 59

lock, membranes

Question 60

SNAREs: Fusion may be triggered by specific ______ signals by removing _____ proteins that prevent complete fusion

Answer 60

extracellular, inhibitory

Question 61

Dissociation of SNARE pairs involves what?

Answer 61

accessory proteins, NSF, and ATP

Question 62

____ _____ proteins are packaged into _____ coated transport vesicles of the ER.

Answer 62

Newly synthesized, COPII

Question 63

COPII coated transport vesicles bud off from ER ___ ____.

Answer 63

exit sites

Question 64

Entry into vesicle is a ______ process

Answer 64

selective

Question 65

Proteins display ___ ____ on cytosolic surface. These are recognized by receptors present on COPII coat.

Answer 65

exit signals

Question 66

______ _____ - incompletely folded/misfolded proteins are retained in ER by binding to chaperone proteins such as ____ or ______. Such proteins are degraded.

Answer 66

Quality control Bip calnexin

Question 67

After budding from ER exit sites and shedding their coat, vesicles _____ with each other.

Answer 67

Fuse

Question 68

_______: fusion of vesicles from same compartment.

Answer 68

Homotypic

Question 69

______: fusion of vesicles from different compartments.

Answer 69

Heterotypic

Question 70

Fusion requires _______; both membranes contribute v- and t- _______

Answer 70

SNAREs, SNAREs

Question 71

Fused structures are called ____ ____ _____.

Answer 71

Vesicular tubular clusters

Question 72

Vesicular tubular clusters are _____-_____: move along microtubules to Golgi, fuse and deliver contents

Answer 72

Short-lived

Question 73

In the retrieval pathway, large vesicles bud off to form smaller vesicles coated with _____.

Answer 73

COPI

Question 74

The retrieval pathway is a mechanism to:

Answer 74

return proteins to ER

Question 75

Retrieval pathway depends on __ ____ ___

Answer 75

ER retrieval signals

Question 76

Example - ______ ____ (present in ER membrane proteins) and ____ ____ (present in soluble proteins) at C terminus

Answer 76

KKXX sequence, | KDEL sequence

Question 77

_______ signal interacts with COPI and packaged into COPI-caoted vesicles.

Answer 77

KKXX

Question 78

Soluble proteins need a ____ _____ which packages them into COPI-coated vesicles.

Answer 78

KDEL receptor

Question 79

Describe the Golgi Apparatus structure

Answer 79

Collection of flattened, membrane-enclosed compartments (cisternae) Each Golgi stack has 2 faces: cis or entry and trans or exit.

Question 80

___ ___ ____ is a network of fused vesicular tubular clusters arriving from ER. Proteins and lipids enter Golgi via this.

Answer 80

Cis Golgi Network (CGN)

Question 81

____ _____ ____ is the region that allows exit of proteins and lipids to next step of secretory pathway.

Answer 81

Trans Golgi Network (TGN)

Question 82

______ plays an important role in protein glycosylation

Answer 82

Golgi