Extended Data Fig. 1: AMPARs with tethered TARP auxiliary subunits faithfully reproduce the gating behaviour of native AMPARs.
From: GluA2-containing AMPA receptors form a continuum of Ca2+-permeable channels
a. (Upper) Example electrophysiological records of L-Glu responses (10 mM) of GluA1/A2 AMPAR heteromers co-expressed with (left) or tethered to (right) TARP γ2. (Lower) Statistical analyses of the degree of AMPAR desensitization (left, SS/Pk) or rate of onset of desensitization (right, τfast) reveals that the gating properties are indistinguishable when co-expressed with or tethered to TARP γ2. (Adapted from Perozzo et al., 2023). b. Plots comparing the gating properties of recombinant A1/A2 heteromers (orange symbol) and native (black symbol) AMPARs expressed by inhibitory stellate (upper) and Purkinje (lower) cells from the cerebellum. In both cases, recombinant AMPARs were expressed as fusion proteins with TARP γ2 tethered to either GluA1 or GluA2 subunit (upper) or to both (lower). Importantly, the desensitization properties of recombinant receptor exactly matched with functional behavior of stellate cells when only two TARP γ2 subunits were present (upper) whereas the Purkinje cell data was exactly matched by recombinant data where all four AMPAR subunits were tethered to TARP γ2. (Adapted from Perozzo et al., 2023). c. Desensitization rates (τdes) of native and recombinant AMPARs arranged in ascending order shows that they form a continuum of functional behavior. Values for native data were taken from Geiger et al.16 and Dawe et al.31 and the values for the recombinant were taken from this study. The black bars correspond to AMPAR heteromers that are tethered to at least two TARP subunits whereas the unfilled bar corresponds to GluA1/A2 heteromers lacking TARPs.
