Abstract
We wanted to analyze the basis for the distinction between OX(1) and OX(2) orexin receptors by the known agonists, orexin-A, orexin-B and Ala(11), D-Leu(15)-orexin-B, of which the latter two show some selectivity for OX(2). For this, chimaeric OX(1)/OX(2) and OX(2)/OX(1) orexin receptors were generated. The receptors were transiently expressed in HEK-293 cells, and potencies of the agonists to elicit cytosolic Ca(2+) elevation were measured. The results show that the N-terminal regions of the receptor are most important, and the exchange of the area from the C-terminal part of the transmembrane helix 2 to the transmembrane helix 4 is enough to lead to an almost total change of the receptor's ligand profile.
Copyright © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Binding Sites / genetics
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Dose-Response Relationship, Drug
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HEK293 Cells
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Humans
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Intracellular Signaling Peptides and Proteins / chemistry
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Intracellular Signaling Peptides and Proteins / pharmacology*
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Models, Molecular
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Molecular Sequence Data
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Mutation
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Neuropeptides / chemistry
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Neuropeptides / pharmacology*
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Orexin Receptors
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Orexins
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Protein Isoforms / agonists
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Protein Isoforms / chemistry
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Protein Isoforms / genetics
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Protein Structure, Secondary
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Receptors, G-Protein-Coupled / agonists*
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Receptors, G-Protein-Coupled / chemistry
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Receptors, G-Protein-Coupled / genetics
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Receptors, Neuropeptide / agonists*
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Receptors, Neuropeptide / chemistry
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Receptors, Neuropeptide / genetics
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Recombinant Fusion Proteins / agonists*
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Recombinant Fusion Proteins / chemistry
Substances
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HCRT protein, human
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Intracellular Signaling Peptides and Proteins
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Neuropeptides
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Orexin Receptors
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Orexins
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Protein Isoforms
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Receptors, G-Protein-Coupled
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Receptors, Neuropeptide
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Recombinant Fusion Proteins