SNAREs Flashcards

1
Q

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

A

Exocytosis
Endocytosis
Intracellular transport
Mitochondrial function
cell division
virus entry

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2
Q

exocytosis and its need for membrane fusion

A

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

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3
Q

Endocytosis and its need for membrane fusion

A

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

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4
Q

Intracellular transport and its need for membrane fusion

A

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

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5
Q

virus entry and its need for membrane fusion

A

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

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6
Q

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

A

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

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7
Q

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

A

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

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8
Q

How does the NSF-SNAP factor work

A

-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

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9
Q

What is the role of Sec1 in vesicle binding

A

Promotes the reaction from vesicle SNARE proteins to the target membranes

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10
Q

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

A

regulating assembly and disassembly of the SNARE complex

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11
Q

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

A

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

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12
Q

Sec18- encodes what enzyme?

A

NSF- meaning sec17 and sec18 work in conjuction

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13
Q

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

A

VAMP

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14
Q

Protein complex- name of proteins found on the target membrane

A

Syntaxin, SNAP25

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15
Q

how is membrane fusion using SNAREs energetically favourable

A

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

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16
Q

1 R SNARE=

A

Vamp

17
Q

3 Q SNAREs=

A

2 SNAP25, 1 Syntaxin

18
Q

what additional machinery can contribute to SNARE specificity

A

Rabs, Coat proteins, and tethers

19
Q

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

A

-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

20
Q

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

A

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

21
Q

3 main structures that make up Clostridial Neurotoxins

A
  1. Targeting domain
  2. Translocation domain
  3. Protease domain
22
Q

what do the toxins from Clostridial Neurotoxins rely on- element

A

Zinc dependent

23
Q

What does the targeting domain do In Clostridial neurotoxins

A

Gets the complex to the neurone

24
Q

Role of the Translocation domain in Clostridial NTs

A

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

25
Q

What do these Clostridial NTs target?

A

Cleave SNAREs

26
Q

which part of the SNARE complex does the botulinum neurotoxin target

A

SNAP25 protein, of the SNARE

27
Q

which part of the SNARE complex does the Tetanus neurotoxin target

A

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

28
Q

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

A

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