Functional expression of a locust tyramine receptor in murine erythroleukaemia cells


Dr J. Vanden Broeck, Laboratory for Developmental Physiology and Molecular Biology, Zoological Institute, KULeuven, Naamsestraat 59, B-3000 Leuven, Belgium. Tel.: 32 16 323978; fax: 32 16 323902; e-mail:


The LCR/MEL system (Locus Control Region/Murine Erythroleukaemia cells) was employed to express and characterize the Locusta migratoria tyramine receptor (TyrLoc), an insect G protein-coupled receptor. Functional agonist-dependent responses were recorded in stable, tyramine receptor expressing cell clones (MEL-TyrLoc). Tyramine elicited a dose-dependent increase of cytosolic Ca2+-ions and an attenuation of forskolin-induced cyclic adenosine monophosphate (AMP) production. Octopamine was shown to be a weak agonist for both responses. In addition, yohimbine proved to be a potent tyramine receptor antagonist. This study reports the first application of the LCR/MEL expression system in functional assays for G protein-coupled receptors and therefore expands the capabilities of this system by exploiting the functionality of the signal transduction pathways.