FUNCTIONAL-CHARACTERIZATION OF THE DROSOPHILA 5-HTDRO1 AND 5-HTDRO2B SEROTONIN RECEPTORS IN INSECT CELLS - ACTIVATION OF A G(ALPHA-S)-LIKE PROTEIN BY 5-HTDRO1 BUT LACK OF COUPLING TO INHIBITORY G-PROTEINS BY 5-HTDRO2B

Insect cells are routinely used for the production of receptor protein s. Expression of the Drosophila 5-HTdro1 serotonin receptor resulted i n positive coupling of the receptor to adenylyl cyclase via the G(alph a s) G-protein subtype. The Drosophila 5-HTdro2B receptor stimulated t he metabolism of inositol phospholipid via a pertussis toxin-insensiti ve G-protein, but exhibited no detectable inhibition of adenylyl cycla se. Immunoblot analysis of the endogenous G-proteins revealed that Sf9 cells lack the G-protein subtypes G(alpha i1-3) and G alpha o, but ex press the subtypes G(alpha s) and G(alpha q).