Invertebrate Neuroscience

, Volume 13, Issue 1, pp 71–84

Characterisation of AmphiAmR4, an amphioxus (Branchiostoma floridae) α2-adrenergic-like G-protein-coupled receptor

Original Paper

DOI: 10.1007/s10158-012-0145-6

Cite this article as:
Bayliss, A. & Evans, P.D. Invert Neurosci (2013) 13: 71. doi:10.1007/s10158-012-0145-6

Abstract

Little is known about the evolutionary relationship between vertebrate adrenergic receptors and invertebrate octopamine and tyramine receptors. The complexity of the adrenergic signalling system is believed to be an innovation of the vertebrate lineage but the presence of noradrenaline has been reported in some invertebrate species. The cephalochordate, amphioxus (Branchiostoma floridae), is an ideal model organism for studying the evolution of vertebrate GPCRs, given its unique position at the base of the chordate lineage. Here, we describe the pharmacological characterisation and second messenger coupling abilities of AmphiAmR4, which clusters with α2-adrenergic receptors in a phylogenetic tree but also shares a high sequence similarity to invertebrate octopamine/tyramine receptors in both BLAST and Hidden Markov Model analyses. Thus, it was of particular interest to determine if AmphiAmR4 displayed similar functional properties to the vertebrate α2-adrenergic receptors or to invertebrate octopamine or tyramine receptors. When stably expressed in Chinese hamster ovary (CHO) cells, noradrenaline couples the receptor to both the activation of adenylyl cyclase and to the activation of the MAPKinase pathway. Pharmacological studies with a wide range of agonists and antagonists suggest that AmphiAmR4 functions as an α2-adrenergic-like receptor when expressed in CHO cells.

Keywords

α2-Adrenergic receptorGPCRAmphioxusCyclic AMPMAPKinaseExpression in Chinese hamster ovary cells

Abbreviations

CHO

Chinese hamster ovary

D-PBS

Dulbecco’s phosphate-buffered saline

ERK

Extracellular signal-related kinase

FBS

Foetal bovine serum

GFP

Green fluorescent protein

GPCR

G-protein-coupled receptor

5-HT

5-Hydroxytryptamine

IBMX

3-Isobutyl methyl xanthine

MAPK

Mitogen-activated protein kinase

ORF

Open reading frame

TM

Transmembrane domain

Supplementary material

10158_2012_145_MOESM1_ESM.docx (560 kb)
Supplementary material 1 (DOCX 559 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  1. 1.The Inositide LaboratoryThe Babraham InstituteCambridgeUK