Regulation and functional consequences of mGlu₄ RNA editing

Response of edited/nonedited mGlu₄ receptor dimers. (A) Schematic representation of the use of GABA_B receptor carboxy-terminal tails to restrict surface expression exclusively to heterodimers. (B) Concentration-response curves comparing cells transfected with equal microgram amounts of an mGlu₄ control construct, mGlu₄ GABA_B tailed receptor constructs together, or tailed constructs alone plus an empty vector control. All constructs in this subfigure are nonedited at the Q124 residue. (C) Max response for the Gb1/Gb2 receptor combination was lower in comparison to wild-type mGlu₄ in the DMSO-matched condition. (*) P ≤ 0.05; (**) P ≤ 0.01. (D) Concentration-response curves for HEK293A-GIRK cells cotransfected with chimeric mGlu₄ constructs restricting surface dimer populations to those of two nonedited receptors or Q124R edited/nonedited receptor heterodimers. Mean ± S.E.M. n = 3. (E) Maximal response values and (F) glutamate potency (pEC₅₀) from the nonlinear regression curves shown in D. Each receptor pair is compared to the nonedited receptor condition using a one-way paired ANOVA with Sidak's post hoc analysis.