SNAREs II

Question 1

What happens when membrane fusion is inhibited in animals?

Answer 1

Paralysis.
Vesicles accumulate

Question 2

What happens when VAMP2, Syntaxin 1a, Syntaxin 1b and SNAP 25 are knocked out of mice?

Answer 2

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

Question 3

How can SNARE mutations be tested?

Answer 3

TURF. (Fusion assay).
An artificial vesicle is created (liposome)
Insert SNAREs and fluorescently tagged.
When vesicles fuse, the dye shows.

Question 4

What type of mutation is S75P?

Answer 4

Dominant negative mutation

Question 5

What is Familial hemophagocytic lymphohistocytosis?

Answer 5

A rare disease of the immune system.
Over proliferation of T Cells, killer cells, B cells, macrophages.
Immune system is overactivated.

Question 6

What is familial hemophagocytic lymphohistocytosis caused by?

Answer 6

Reduced levels of STX11

Question 7

What are two clostridial neurotoxins?

Answer 7

Tetanus
Botulism

Question 8

How much of a clostridial neurotoxin is lethal?

Answer 8

1-2ng/kg

Question 9

What do clostridial neurotoxins do?

Answer 9

Taken up by neurons and cleave SNAREs. Each toxin is specific for a SNARE.

Question 10

What do tetanus and botA cleave?

Answer 10

VAMP2

Question 11

What does botox cleave?

Answer 11

SNAP25

Question 12

What are clinical uses of Botulinum neurotoxins?

Answer 12

Botox (BotA)
Muscle issues/spasms

Question 13

Why can tetanus not be used for clinical uses?

Answer 13

Most people are vaccinated against tetanus.

Question 14

Tetanus and BotB cleave the same target but why do they have different effects?

Answer 14

They act upon different neurons.
Botulism acts upon neuromuscular junctions
Tetanus acts upon inhibitory neurones.