A new family of insect tyramine receptors

Biochem Biophys Res Commun. 2005 Dec 16;338(2):1189-96. doi: 10.1016/j.bbrc.2005.10.058. Epub 2005 Oct 21.


The Drosophila Genome Project database contains a gene, CG7431, annotated to be an "unclassifiable biogenic amine receptor." We have cloned this gene and expressed it in Chinese hamster ovary cells. After testing various ligands for G protein-coupled receptors, we found that the receptor was specifically activated by tyramine (EC(50), 5x10(-7)M) and that it showed no cross-reactivity with beta-phenylethylamine, octopamine, dopa, dopamine, adrenaline, noradrenaline, tryptamine, serotonin, histamine, and a library of 20 Drosophila neuropeptides (all tested in concentrations up to 10(-5) or 10(-4)M). The receptor was also expressed in Xenopus oocytes, where it was, again, specifically activated by tyramine with an EC(50) of 3x10(-7)M. Northern blots showed that the receptor is already expressed in 8-hour-old embryos and that it continues to be expressed in all subsequent developmental stages. Adult flies express the receptor both in the head and body (thorax/abdomen) parts. In addition to the Drosophila tyramine receptor gene, CG7431, we found another closely related Drosophila gene, CG16766, that probably also codes for a tyramine receptor. Furthermore, we annotated similar tyramine-like receptor genes in the genomic databases from the malaria mosquito Anopheles gambiae and the honeybee Apis mellifera. These four tyramine or tyramine-like receptors constitute a new receptor family that is phylogenetically distinct from the previously identified insect octopamine/tyramine receptors. The Drosophila tyramine receptor is, to our knowledge, the first cloned insect G protein-coupled receptor that appears to be fully specific for tyramine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • CHO Cells
  • Conserved Sequence
  • Cricetinae
  • Cricetulus
  • Drosophila melanogaster / metabolism*
  • Insecta
  • Molecular Sequence Data
  • Receptors, Biogenic Amine / chemistry*
  • Receptors, Biogenic Amine / classification
  • Receptors, Biogenic Amine / metabolism*
  • Sequence Homology, Amino Acid
  • Tyramine / metabolism*


  • Receptors, Biogenic Amine
  • tyramine receptor
  • Tyramine

Associated data

  • GENBANK/AY034617
  • GENBANK/BK005538
  • GENBANK/BK005541