News about the neuronal membrane protein which binds the presynaptic neurotoxin beta-bungarotoxin

beta-Bungarotoxin (beta-Btx) is cytotoxic for GABA-ergic and cholinergic neurons in chick retina explant cultures. Binding experiments with 125I-beta-Btx identified a high affinity binding site in membranes of chick brain. This binding is specific and its pharmacology indicates that it mediates the above-mentioned cytotoxicity. Photoaffinity crosslinking of 125I-beta-Btx to chick brain membranes showed that the beta-Btx binding protein contains a polypeptide of MW 95 000. The beta-Btx binding protein was solubilized with Triton X-100 and some of its biochemical and physical properties were characterized.