Latrotoxin and Bungarotoxin Flashcards
Where does beta-bungarotoxin act?
Presynaptically.
Where does alpha-bungarotoxin act?
Postsynaptically.
In which three locations does beta-bungarotoxin inhibit acetylcholine release?
Synaptic vesicular proteins, e.g. SNAREs.
Presynaptic calcium channels.
Phospholipase A2.
Describe the different effects of the A-chain and B-chain in beta-bungarotoxin.
A-chain has phospholipase A2-like effects.
B-chain induces apoptosis.
What is the primary mechanism of action of beta-bungarotoxin?
Phosphorylation of MARCKS protein to inhibit acetylcholine release.
Describe the mechanism of action of alpha-bungarotoxin.
Binds competitively, rapidly and almost irreversibly to the nAChR at the NMJ.
Latrotoxins are found in which animal’s venom?
Black widow spider.
Latrotoxins can exist in which two forms?
Dimer or tetramer.
How do dimer latrotoxins work?
Bind and signal via latrophilin.
How do tetramer latrotoxins work?
Insert and form pores that pass calcium ions.
Latrophilin is part of a class of GPCRs called what?
Adhesion GPCRs.
What is thought to be the function of latrophilin GPCRs?
To help with tactile sensation.
How can we use mutant alpha-latrotoxin in lab experiments?
Does not form pores, so increases NT release during experiments.
Allows us to explore receptor function.
