Figure 2. Asymmetric transduction results from the HDs in the mGlu2-4 heterodimer.

In (A), (B) and (C) cartoons illustrating the heterodimer combinations used with one or both subunits carrying the FS mutation (red cross) that prevents G protein activation are indicated on the top. For each subunit, white domains are from mGlu2, while the grey domains are from mGlu4. The chimeric protein made of mGlu2 ECD and mGlu4 HD is named 2^ECD4^HD and the reverse chimera named 4^ECD2^HD. The intracellular Ca²⁺ responses mediated by the indicated subunit compositions (color coded, as indicated on top of the cartoons) upon stimulation with DCG-IV (30 μM), L-AP4 (30 μM) or glutamate (1 mM) shown at the bottom. (A) Data obtained with heterodimers containing both ECDs (VFT and CRD) from mGlu2. (B) Data obtained with heterodimers containing both ECDs from mGlu4. (C) Data obtained with heterodimers in which the ECDs were swapped between the two subunits. Data are means ±SEM (n ≥ 3). **p<0.01, ***p<0.001 (unpaired t test).

Figure 2—figure supplement 1. Asymmetric transduction results from the HDs in the mGlu2-4 heterodimer.

Same as Figure 2 excepted that only the VFT is swapped, and not the entire CRD. In (A), (B) and (C) cartoons illustrating the heterodimer combinations used with one or both subunits carrying the FS mutation (red cross) that prevents G protein activation are indicated on the top. For each subunit, white domains are from mGlu2, while the grey domains are from mGlu4. The chimeric protein made of mGlu2 VFT and mGlu4 CRD + HD is named 2^VFT4^HD and the reverse chimera named 4^VFT2^HD. The intracellular Ca²⁺ responses mediated by the indicated subunit compositions (color coded, as indicated on top of the cartoons) upon stimulation with DCG-IV (30 μM), L-AP4 (30 μM) or glutamate (1 mM) shown at the bottom. (A) Data obtained with heterodimers containing both VFT from mGlu2. (B) Data obtained with heterodimers containing both VFTs from mGlu4. (C) Data obtained with heterodimers in which the VFTs were swapped between the two subunits. Data are means ±SEM (n ≥ 3). **p<0.01, ***p<0.001 (unpaired t test).

Figure 2—figure supplement 2. Cell surface and total expression of various mGlu dimer combination.

Quantification of cell surface-total expression of HA-tagged or Flag-tagged constructs by ELISA on intact cells transfected with the indicated subunits as in Figure 2. Data were generated from the same cells used in Figure 2 and are means ±SEM of triplicates from a typical experiment repeated at least three times.

Figure 2—figure supplement 3. Cell surface and total expression of various mGlu dimer combination.

Quantification of cell surface-total expression of HA-tagged or Flag-tagged constructs by ELISA on intact cells transfected with the indicated subunits as in Sup Figure 4. Data were generated from the same cells used in Sup Figure 4 and are means ±SEM of triplicates from a typical experiment repeated at least three times.