SNAREs Flashcards
List some (6) systems which require membrane fusion- therefore SNARE proteins
Exocytosis
Endocytosis
Intracellular transport
Mitochondrial function
cell division
virus entry
exocytosis and its need for membrane fusion
release of neurotransmitters from neurones
and digestive enzymes- pancreatic cells
membrane fusion between secretory vesicles and the plasma membrane
Endocytosis and its need for membrane fusion
various forms of endocytosis
clatherin-mediated endocytosis and phagocytosis
II) uptake of nutrients, particles and molecules into cells
Intracellular transport and its need for membrane fusion
allowing vesicles to move cargo between organelles within the cell
examples- endoplasmic reticulum, Golgi and lysosomes
virus entry and its need for membrane fusion
certain viruses like HIV, use membrane fusion to enter host cells
why SNARE molecules are required to drive membrane fusion (4)
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
what type of enzyme is NSF, and what does it do?
ATPase
uses a molecule called SNAP to break apart/ recycle SNARE complexes
How does the NSF-SNAP factor work
-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
What is the role of Sec1 in vesicle binding
Promotes the reaction from vesicle SNARE proteins to the target membranes
Due to the control Sec1 has on SNARE proteins, what other role do they have in regulation
regulating assembly and disassembly of the SNARE complex
Sec17 is used with NSF, what is its role beside NSF
Sec17 will bind to the SNARE complex and aim to recruit NSF molecules- for ATP
Help in disassembly of the complex
Sec18- encodes what enzyme?
NSF- meaning sec17 and sec18 work in conjuction
what part of the SNARE complex is found on the vesicle before the membrane driving
VAMP
Protein complex- name of proteins found on the target membrane
Syntaxin, SNAP25
how is membrane fusion using SNAREs energetically favourable
usually without the SNARE complex it is unfavourable
with= when it comes to disassemble the complex, hydrolysed ATP releases the energy stored
1 R SNARE=
Vamp
3 Q SNAREs=
2 SNAP25, 1 Syntaxin
what additional machinery can contribute to SNARE specificity
Rabs, Coat proteins, and tethers
Activation of Synaptotagmin, how its activated, and its interactions with the SNARE
-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
Regulation of Ca2+ on synaptotagmin, and how Ca2+ release is promoted (in a synapse e.g)
When an AP reaches the presynaptic terminal= channel proteins will open allowing Calcium ion release
3 main structures that make up Clostridial Neurotoxins
- Targeting domain
- Translocation domain
- Protease domain
what do the toxins from Clostridial Neurotoxins rely on- element
Zinc dependent
What does the targeting domain do In Clostridial neurotoxins
Gets the complex to the neurone
Role of the Translocation domain in Clostridial NTs
gets taken up by vesicles and breaks out, into the cytoplasm
What do these Clostridial NTs target?
Cleave SNAREs
which part of the SNARE complex does the botulinum neurotoxin target
SNAP25 protein, of the SNARE
which part of the SNARE complex does the Tetanus neurotoxin target
the VAMP protein of the SNARE-
mostly neurotransmitters at inhibitory synapses
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
