Similar ligand binding in recombinant human alpha 2 C2-adrenoceptors produced in mammalian, insect and yeast cells.

Ligand binding properties were investigated in recombinant human alpha 2C2-adrenoceptors expressed in three different host systems: Shionogi S115 mouse mammary tumour cells, Spodoptera frugiperda Sf9 insect cells and Saccharomyces cerevisiae yeast cells. The expected 43 kDa alpha 2C2 protein was visualized with immunoblotting using a polyclonal alpha 2C2-receptor antibody. [3H]Rauwolscine binding in cell homogenates or membranes (Bmax 3-11 pmol/mg protein; Kd approximately 5.5 nM) was inhibited by prazosin, oxymetazoline, RX821002, chlorpromazine and (-)-noradrenaline with and without the GTP-analogue Gpp(NH)p with similar Ki values in the different host systems. This indicates that alpha 2C2-adrenoceptors retain their binding characteristics irrespective of the host environment.