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=

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
What do these Clostridial NTs target?
Cleave SNAREs
26
which part of the SNARE complex does the botulinum neurotoxin target
SNAP25 protein, of the SNARE
27
which part of the SNARE complex does the Tetanus neurotoxin target
the VAMP protein of the SNARE- mostly neurotransmitters at inhibitory synapses
28
how can Botulinum toxins treat neurological conditions- think inhibitory/ stops sweating e.g
migraines- inhibits pain neurotransmitters etc stopping certain neurotransmitter release for non-necessary results