Similar ligand binding in recombinant human α₂C2-adrenoceptors produced in mammalian, insect and yeast cells

Ligand binding properties were investigated in recombinant human α₂C2-adrenoceptors expressed in three different host systems: Shionogi S115 mouse mammary tumour cells, Spodoptera frugiperda Sf9 insect cells and Saccharomyces cerevisae yeast cells. The expected 43 kDa α₂C2 protein was visualized with immunoblotting using a polyclonal α₂C2-receptor antibody. [³H]Rauwolscine binding in cell homogenates or membranes (B_max 3-11 pmol/mg protein; K_d approximately 5.5 nM) was inhibited by prazosin, oxymetazoline, RX821002, chlorpromazine and (-)-noradrenaline with and without the GTP-analogue Gpp(NH)p with similar K_i values in the different host systems. This indicates that α₂C2-adrenoceptors retain their binding characteristics irrespective of the host environment.