SNAREs II Flashcards
What happens when membrane fusion is inhibited in animals?
Paralysis.
Vesicles accumulate
What happens when VAMP2, Syntaxin 1a, Syntaxin 1b and SNAP 25 are knocked out of mice?
VAMP2: Die at birth, reduced synaptic transmission
Syntaxin 1a: No gross abnormalities
Syntaxin 1b: Die at birth, reduced synaptic transmission
SNAP25: Die at birth, reduced synaptic transmission
How can SNARE mutations be tested?
TURF. (Fusion assay).
An artificial vesicle is created (liposome)
Insert SNAREs and fluorescently tagged.
When vesicles fuse, the dye shows.
What type of mutation is S75P?
Dominant negative mutation
What is Familial hemophagocytic lymphohistocytosis?
A rare disease of the immune system.
Over proliferation of T Cells, killer cells, B cells, macrophages.
Immune system is overactivated.
What is familial hemophagocytic lymphohistocytosis caused by?
Reduced levels of STX11
What are two clostridial neurotoxins?
Tetanus
Botulism
How much of a clostridial neurotoxin is lethal?
1-2ng/kg
What do clostridial neurotoxins do?
Taken up by neurons and cleave SNAREs. Each toxin is specific for a SNARE.
What do tetanus and botA cleave?
VAMP2
What does botox cleave?
SNAP25
What are clinical uses of Botulinum neurotoxins?
Botox (BotA)
Muscle issues/spasms
Why can tetanus not be used for clinical uses?
Most people are vaccinated against tetanus.
Tetanus and BotB cleave the same target but why do they have different effects?
They act upon different neurons.
Botulism acts upon neuromuscular junctions
Tetanus acts upon inhibitory neurones.
