SNAREs

Question 1

List some (6) systems which require membrane fusion- therefore SNARE proteins

Answer 1

Exocytosis
Endocytosis
Intracellular transport
Mitochondrial function
cell division
virus entry

Question 2

exocytosis and its need for membrane fusion

Answer 2

release of neurotransmitters from neurones
and digestive enzymes- pancreatic cells
membrane fusion between secretory vesicles and the plasma membrane

Question 3

Endocytosis and its need for membrane fusion

Answer 3

various forms of endocytosis
clatherin-mediated endocytosis and phagocytosis
II) uptake of nutrients, particles and molecules into cells

Question 4

Intracellular transport and its need for membrane fusion

Answer 4

allowing vesicles to move cargo between organelles within the cell
examples- endoplasmic reticulum, Golgi and lysosomes

Question 5

virus entry and its need for membrane fusion

Answer 5

certain viruses like HIV, use membrane fusion to enter host cells

Question 6

why SNARE molecules are required to drive membrane fusion (4)

Answer 6

zipping- pulling membranes closer together
Energy req- SNAREs provide the energy needed
Specificity-
Regulation- regulated by factors like Ca2+ and accessory proteins- control over timings, and location of fusion events

Question 7

what type of enzyme is NSF, and what does it do?

Answer 7

ATPase
uses a molecule called SNAP to break apart/ recycle SNARE complexes

Question 8

How does the NSF-SNAP factor work

Answer 8

-NSF is an ATPase= can hydrolyse to produce ATP
-SNAP is a molecule able to attach to the SNARE complex allowing disassembly
-Lots of energy is required for the disassembly of the SNARE complex from the other SNARE protein

Question 9

What is the role of Sec1 in vesicle binding

Answer 9

Promotes the reaction from vesicle SNARE proteins to the target membranes

Question 10

Due to the control Sec1 has on SNARE proteins, what other role do they have in regulation

Answer 10

regulating assembly and disassembly of the SNARE complex

Question 11

Sec17 is used with NSF, what is its role beside NSF

Answer 11

Sec17 will bind to the SNARE complex and aim to recruit NSF molecules- for ATP
Help in disassembly of the complex

Question 12

Sec18- encodes what enzyme?

Answer 12

NSF- meaning sec17 and sec18 work in conjuction

Question 13

what part of the SNARE complex is found on the vesicle before the membrane driving

Answer 13

VAMP

Question 14

Protein complex- name of proteins found on the target membrane

Answer 14

Syntaxin, SNAP25

Question 15

how is membrane fusion using SNAREs energetically favourable

Answer 15

usually without the SNARE complex it is unfavourable
with= when it comes to disassemble the complex, hydrolysed ATP releases the energy stored

Question 16

1 R SNARE=

Answer 16

Vamp

Question 17

3 Q SNAREs=

Answer 17

2 SNAP25, 1 Syntaxin

Question 18

what additional machinery can contribute to SNARE specificity

Answer 18

Rabs, Coat proteins, and tethers

Question 19

Activation of Synaptotagmin, how its activated, and its interactions with the SNARE

Answer 19

-Ca2+ ions bind to synaptotagmin, causing a conformation change in the protein
-Activated Synaptotagmin interacts w/ SNAREs (VAMPS protein specifically)
-enhances SNAREs ability to promote membrane fusion

Question 20

Regulation of Ca2+ on synaptotagmin, and how Ca2+ release is promoted (in a synapse e.g)

Answer 20

When an AP reaches the presynaptic terminal= channel proteins will open allowing Calcium ion release

Question 21

3 main structures that make up Clostridial Neurotoxins

Answer 21

1. Targeting domain
2. Translocation domain
3. Protease domain

Question 22

what do the toxins from Clostridial Neurotoxins rely on- element

Answer 22

Zinc dependent

Question 23

What does the targeting domain do In Clostridial neurotoxins

Answer 23

Gets the complex to the neurone

Question 24

Role of the Translocation domain in Clostridial NTs

Answer 24

gets taken up by vesicles and breaks out, into the cytoplasm

Question 25

What do these Clostridial NTs target?

Answer 25

Cleave SNAREs

Question 26

which part of the SNARE complex does the botulinum neurotoxin target

Answer 26

SNAP25 protein, of the SNARE

Question 27

which part of the SNARE complex does the Tetanus neurotoxin target

Answer 27

the VAMP protein of the SNARE-
mostly neurotransmitters at inhibitory synapses

Question 28

how can Botulinum toxins treat neurological conditions- think inhibitory/ stops sweating e.g

Answer 28

migraines- inhibits pain neurotransmitters etc
stopping certain neurotransmitter release for non-necessary results