protein targeting and export 5.1

Question 1

how do transport vesicles identify their target membrane

Answer 1

snare proteins which exist in pairs

Question 2

V-SNARE

T-SNARE

Answer 2

on surface of vesicle

on membrane of target

Question 3

what do the snares have

Answer 3

helices that interact with one another

and dock the vesicle to the target membrane

Question 4

how is interaction initiated

Answer 4

by a vesicle specific Rab GTPase

Question 5

vesicle docking step 1

what happens

Answer 5

Rab- GTP proteins on vesicle surface binds to specific Rab-effecter in the target membrane
brings V/T in close proximity allowing docing

Question 6

vesicle docking step 2

Answer 6

alpha helices of V/T form a coiled coil

bringing the 2 close together

Question 7

membrane fusion step 3

Answer 7

fuses together after they are forced into close proximity
complex of 2 proteins
NSF and alpha -SNAP, binds to empty snare complex

Question 8

membrane fusion step 4

Answer 8

ATP hydrolysis (catalysed by NSF) causes disassembly

Question 9

influenza virus expressed what as a viral coat

Answer 9

hemaggkutinin HA

Question 10

what does HA do

Answer 10

binds to sialic acid (o-glycosylation) on the surface of erythrocytes or cells of the upper respiratory tract
virus taken up and targets endosomes (low pH)

Question 11

why does the virus need a low PH

Answer 11

to denature coat and let the virus in