Characterization Of Curaremimetic Neurotoxin Binding Sites On Membrane Fractions Derived From The Human Medulloblastoma Clonal Line Te671
Studies were conducted on curaremimetic neurotoxin binding to the nicotinic acetylcholine receptor present on membrane fractions derived from the human medulloblastoma clonal line, TE671. Highâ€affinity binding sites (KD= 2 nM for 1â€h incubation at 20Â°C) and lowâ€affinity binding sites (KD= 40 nM) for 125Iâ€labeled Î±â€bungarotoxin are present in equal quantities (60 fmol/mg membrane protein). The kinetically determined dissociation constant for highâ€affinity binding of toxin is 0.56 nM (k1= 6.3 Â· 10âˆ’1 minâˆ’1 nMâˆ’1; kâ€1= 3.5 Â· 10âˆ’3 minâˆ’1) at 20Â°C. Nicotine, dâ€tubocurarine, and acetylcholine are among the most effective inhibitors of highâ€affinity toxin binding. The quantity of toxin binding sites and their affinity for cholinergic agonists is sensitive to reduction, alkylation, and/or oxidation of membrane sulthydryl residues. Highâ€affinity toxin binding sites that have been subjected to reaction with the sulthydryl reagent dithiothreitol are irreversibly blocked by the nicotinic receptor affinity reagent bromoacetylcholine. Highâ€affinity toxin binding is inhibited in the presence of either of two polyclonal antisera or a monoclonal antibody raised against nicotinic acetylcholine receptors from fish electric tissue. Taken together, these results indicate that curaremimetic neurotoxin binding sites on membrane fractions of the TE671 cell line share some properties with nicotinic acetylcholine receptors of peripheral origin and with toxin binding sites on other neuronal tissues. Copyright Â© 1986, Wiley Blackwell. All rights reserved
Journal of Neurochemistry
Digital Object Identifier (DOI)
Lukas, Ronald J., "Characterization Of Curaremimetic Neurotoxin Binding Sites On Membrane Fractions Derived From The Human Medulloblastoma Clonal Line Te671" (1986). Neurobiology. 191.