Figure 1.
Diagrammatic representation of different nAChR assemblies which may be formed by complete (left) or partial (center and right) incorporation of linked constructs into the receptor. B–F show the effects of introducing a reporter mutation (a Thr in the 9′ position of the second transmembrane domain) in different subunits; references are given to the figures that show the results with each combination. The number under each cartoon shows the number of mutation copies expected to be in the gate for each receptor assembly. Note that no heterogeneity in the number of mutation copies is predicted if all α, all β, or no subunits are mutated (A–C) in accord with the experiments in Figs. 2 and 5. Mutating β only in the monomer construct or only in the tandem construct (D and E) can detect the different receptor forms (see the experiments in Figs. 7 and 6, respectively). If receptors are expressed in which both α and βmonomer (F) bear the mutation, some receptors will bear five copies of the mutation (see results).