Functional characterisation of the Drosophila 5‐HTdro1 and 5‐HTdro2B serotonin receptors in insect cells: activation of a Gαs‐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 proteins. Expression of the Drosophila 5-HTdro1 serotonin receptor resulted in positive coupling of the receptor to adenylyl cyclase via the G(alpha)s G-protein subtype. The Drosophila 5-HTdro2B receptor stimulated the metabolism of inositol phospholipid via a pertussis toxin-insensitive G-protein, but exhibited no detectable inhibition of adenylyl cyclase. Immunoblot analysis of the endogenous G-proteins revealed that Sf9 cells lack the G-protein subtypes G(alpha i 1-3) and G(alpha)o, but express the subtype G(alpha)s and G(alpha)q.