Journal of Neuroscience, Vol 6, 481-486, Copyright © 1986 by Society for Neuroscience
Monoclonal antibodies specific to the beta and gamma subunits of the Torpedo acetylcholine receptor inhibit single-channel activity
Y Blatt, MS Montal, JM Lindstrom and M Montal
The functional role of individual ACh receptor subunits in the mechanism of
the nicotinic ACh receptor channel was examined using subunit-specific
monoclonal antibodies (mAbs) as probes. Single-channel recordings from the
Torpedo californica purified ACh receptor reconstituted in planar lipid
bilayers were used as the assay to evaluate the influence of distinct mAbs
on the ion conduction and gating characteristics of the ACh receptor
channel. The mAbs that bind to the main immunogenic region on an
extracellular domain of the alpha subunits do not perturb the open-channel
conductance or lifetimes. A mAb that binds to extracellular domains of
alpha and beta subunits and two mAbs that bind to the cytoplasmic surface
of the beta and gamma subunits inhibit single-channel activity. Thus, mAbs
with primary specificity for beta and gamma subunits affect channel gating.
This approach may specify the functional roles of distinct structural
domains in the ACh receptor molecule.