Fig. 2.

Pharmacological validation of TMEM97 as the σ₂ receptor. (A) PC-12 cells treated with Tmem97-targeted or control siRNA were tested to measure Tmem97 mRNA levels (Left) and σ₂ expression by ³H DTG binding (Right). qPCR data are shown as mean ± SD. Radioligand binding data are shown as mean ± SEM and are representative of two independent experiments performed in triplicate. (B) ³H DTG saturation binding on Sf9 insect cell membranes expressing either TMEM97 (red circles) or the negative control β₂ adrenergic receptor (blue squares). (C) ³H DTG competition curves in Sf9 insect cell membranes expressing TMEM97 against the known σ₂ receptor ligands haloperidol (green circles), PB-28 (red squares), (+)-pentazocine (orange hexagons), (+)-SKF-10,047 (blue diamonds), SAS-1121 (purple triangles), and cold DTG (white triangles). (D) ³H DTG competition curves with the known TMEM97 ligands Elacridar (squares, dotted line) and Ro 48-8071 (circles, solid line) in Sf9 insect cell membranes expressing TMEM97 (red) and in MCF-7 cell membranes (blue). For all curves, data points are shown as mean ± SEM and are representative of two independent experiments performed in triplicate.