PUBLICATION
Conserved structural, pharmacological and functional properties among the three human and five zebrafish alpha(2)-adrenoceptors
- Authors
- Ruuskanen, J.O., Laurila, J., Xhaard, H., Rantanen, V.V., Vuoriluoto, K., Wurster, S., Marjamaki, A., Vainio, M., Johnson, M.S., and Scheinin, M.
- ID
- ZDB-PUB-050120-13
- Date
- 2005
- Source
- British journal of pharmacology 144(2): 165-177 (Journal)
- Registered Authors
- Ruuskanen, Jori
- Keywords
- alpha2-Adrenergic receptor, adrenoceptor, ligand binding, molecular evolution, molecular modelling, GPCR, monoamine receptor, protein structure, catecholamine, zebrafish alpha2-Adrenergic receptor, adrenoceptor, ligand binding, molecular evolution, molecular modelling, GPCR, monoamine receptor, protein structure, catecholamine, zebrafish
- MeSH Terms
-
- Animals
- CHO Cells
- Conserved Sequence*
- Cricetinae
- Humans
- Protein Binding/physiology
- Protein Structure, Secondary/physiology
- Receptors, Adrenergic, alpha-2/chemistry*
- Receptors, Adrenergic, alpha-2/classification*
- Receptors, Adrenergic, alpha-2/metabolism
- Zebrafish/metabolism*
- PubMed
- 15655522 Full text @ Br. J. Pharmacol.
Citation
Ruuskanen, J.O., Laurila, J., Xhaard, H., Rantanen, V.V., Vuoriluoto, K., Wurster, S., Marjamaki, A., Vainio, M., Johnson, M.S., and Scheinin, M. (2005) Conserved structural, pharmacological and functional properties among the three human and five zebrafish alpha(2)-adrenoceptors. British journal of pharmacology. 144(2):165-177.
Abstract
Zebrafish has five distinct alpha(2)-adrenoceptors. Two of these, alpha(2Da) and alpha(2Db), represent a duplicated, fourth alpha(2)-adrenoceptor subtype, while the others are orthologue of the human alpha(2A)-, alpha(2B)- and alpha(2C)-adrenoceptors. Here, we have compared the pharmacological properties of these receptors to infer structural determinants of ligand interactions.The zebrafish alpha(2)-adrenoceptors were expressed in Chinese hamster ovary cells and tested in competitive ligand binding assays and in a functional assay (agonist-stimulated [(35)S]GTPgammaS binding). The affinity results were used to cluster the receptors and, separately, the ligands using both principal component analysis and binary trees.The overall ligand binding characteristics, the order of potency and efficacy of the tested agonists and the G-protein coupling of the zebrafish and human alpha(2)-adrenoceptors, separated by approximately 350 million years of evolution, were found to be highly conserved. The binding affinities of the 20 tested ligands towards the zebrafish alpha(2)-adrenoceptors are generally comparable to those of their human counterparts, with a few compounds showing up to 40-fold affinity differences.The alpha(2A) orthologues and the zebrafish alpha(2D) duplicates clustered as close pairs, but the relationships between the orthologues of alpha(2B) and alpha(2C) were not clearly defined. Applied to the ligands, our clustering methods segregated the ligands based on their chemical structures and functional properties. As the ligand binding pockets formed by the transmembrane helices show only minor differences among the alpha(2)-adrenoceptors, we suggest that the second extracellular loop - where significant sequence variability is located - might contribute significantly to the observed affinity differences.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping