Zaidi: Trafficking 1

Question 1

SNARE proteins function

Answer 1

Catalyze fusion of vesicles with membranes

Question 2

Rab proteins

Answer 2

Direct vesicles to specific spots on target membranes

Play central role in specificity of vesicular transport

Question 3

Transport from ER

Answer 3

Newly synthesized proteins are packaged into COPII coated transport vesicles
Entry of cargo into vesicles is selective, proteins display exit signals of cytosolic surface which are recognized by receptors on COPII coat

Question 4

Quality control of misfolded proteins in ER

Answer 4

Non-folded/misfolded proteins are retained in ER by binding to chaperone proteins such as BiP or Calnexin
They are then degraded

Question 5

Heterotypic fusion

Answer 5

Fusion of vesicles from different compartments

Question 6

Clarthrin subunits

Answer 6

3 large and 3 small subunits form triskelion

Triskelions assemble into a basket like structure that form coated pits

Question 7

Retrieval pathway

Answer 7

Large vesicles bud off to form smaller vesicles coated with COPI
Return to ER depends on ER retrieval signals

Question 8

Rab-GEF

Answer 8

Keeps it in active GTP-bound form. This form is tightly bound to membrane

Question 9

Dissociation of SNARE pairs involves

Answer 9

NSF, accessory proteins and ATP

Question 10

Dynamin protein function

Answer 10

Assembles a ring around a clathrin bud

Question 11

Phosphoinositides play a major role in

Answer 11

Coat assembly, vesicle formation and protein trafficking

Question 12

KDEL sequence

Answer 12

ER retrieval signal present in soluble proteins

Need KDEL receptor which packages them into COPI vesicles

Question 13

Two major functions of membrane coat

Answer 13

Concentrates select proteins in a specialized patch for transport
Coat molds the vesicle to form a basketlike lattice that deforms the membrane and gives shape to the vesicle

Question 14

PI’s control

Answer 14

Recruitment and binding of proteins to specific organelles/domains and regulate vesicle trafficking

Question 15

Cis golgi network

Answer 15

Network of fused vesicular tubular clusters arriving from ER

Proteins and lipids enter golgi here

Question 16

Rab-GDP dissociation inhibitor

Answer 16

Keeps it in inactive GDP-bound form. This form is soluble

Question 17

SNARE proteins

Answer 17

Mediate fusion of vesicle with membrane

Question 18

Clathrin coat is lost when

Answer 18

After vesicle formation is completed

Question 19

Dynamin domains

Answer 19

PIP2 binding domain- tethers protein to membrane

GTPase domain- regulates rate of vesicle pinching

Question 20

Golgi plays an important role in

Answer 20

Protein glycosylation

Question 21

Rab1 location

Answer 21

ER and golgi complex

Question 22

COPII coats

Answer 22

Mediate transport from ER

Question 23

Active form of Rab binds

Answer 23

Rab effectors- motor proteins/tethering proteins present on the target membrane

Question 24

Homotypic fusion

Answer 24

Fusion of vesicles from same compartment

Question 25

KKXX sequence

Answer 25

ER retrieval signal present in ER membrane proteins

Interacts with COPI and packaged into COPI vesicles

Question 26

HSP 70 chaperone function in vesicles

Answer 26

Uses ATP to peel off the coat

Question 27

Vesicular tubular clusters

Answer 27

End product of vesicle fusion

Question 28

Adaptor proteins

Answer 28

Form second layer between cage and membrane in clathrin coated vesicles
Bind clathrin and membrane-bound cargo receptors

Question 29

t-SNAREs location

Answer 29

Found on target membrane

Question 30

Clathrin-coated vesicles

Answer 30

Mediate transport from golgi apparatus and plasma membrane

Question 31

Rab5 location

Answer 31

Early endosomes, plasma membrane, clathrin-coated vesicles

Question 32

Trans golgi network

Answer 32

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

Question 33

COPI coats

Answer 33

Mediate transport from golgi cisternae

Question 34

BAR domains

Answer 34

Membrane bending proteins

Question 35

Explain PI binding w/proteins

Answer 35

Different proteins bind with high specificity to the headgroups of particular PI’s

Question 36

Rab3A location

Answer 36

Synaptic/secretory vesicles

Question 37

Phosphinositides can undergo

Answer 37

Rapid cycles of phosphorylation and dephosphorylation to form various derivatives

Question 38

v-SNAREs location

Answer 38

Found of vesicle membrane