QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, October 13, 2004, 24(41):9097-9104; doi:10.1523/JNEUROSCI.2429-04.2004

This Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (32) Citing Articles via Google Scholar Google Scholar Articles by Beene, D. L. Articles by Lummis, S. C. R. Search for Related Content PubMed PubMed Citation Articles by Beene, D. L. Articles by Lummis, S. C. R.

 Previous Article  |  Next Article 

Cellular/Molecular
Tyrosine Residues That Control Binding and Gating in the 5-Hydroxytryptamine₃ Receptor Revealed by Unnatural Amino Acid Mutagenesis

Darren L. Beene,^1 * Kerry L. Price,^3 * Henry A. Lester,² Dennis A. Dougherty,¹ and Sarah C. R. Lummis³

Divisions of ¹Chemistry and Chemical Engineering and ²Biology, California Institute of Technology, Pasadena, California 91125, and ³Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom

The mechanism by which agonist binding triggers pore opening in ligand-gated ion channels is poorly understood. Here, we used unnatural amino acid mutagenesis to introduce subtle changes to the side chains of tyrosine residues (Tyr141, Tyr143, Tyr153, and Tyr234), which dominate the 5-HT₃ receptor binding site. Heterologous expression in oocytes, combined with radioligand binding data and a model of 5-HT (serotonin) computationally docked into the binding site, has allowed us to determine which of these residues are responsible for binding and/or gating. We have shown that Tyr 143 forms a hydrogen bond that is essential for receptor gating but does not affect binding, whereas a hydrogen bond formed by Tyr153 is involved in both binding and gating of the receptor. The aromatic group of Tyr234 is essential for binding and gating, whereas its hydroxyl does not affect binding but plays a steric role in receptor gating. Tyr141 is not involved in agonist binding or receptor gating but is important for antagonist interactions. These data, combined with a new model of the nonliganded 5-HT₃ receptor, lead to a mechanistic explanation of the interactions that initiate the conformational change leading to channel opening. Thus, we suggest that agonist entry into the binding pocket may displace Tyr143 and Tyr153 and results in their forming new hydrogen bonds. These bonds may form part of the network of bond rearrangements that trigger the conformational change leading to channel opening. Similar rearrangements may initiate gating in all Cys-loop receptors.

Key words: ligand-gated ion channel; Cys-loop receptor; 5-HT₃ receptor binding site; hydrogen bond; unnatural amino acids; activation mechanism; serotonin

---

Received April 23, 2004; accepted July 20, 2004.

This article has been cited by other articles:

				S. A. Pless, K. S. Millen, A. P. Hanek, J. W. Lynch, H. A. Lester, S. C. R. Lummis, and D. A. Dougherty A Cation-{pi} Interaction in the Binding Site of the Glycine Receptor Is Mediated by a Phenylalanine Residue J. Neurosci., October 22, 2008; 28(43): 10937 - 10942. [Abstract] [Full Text] [PDF]

				M. Lu, F. Echeverri, D. Kalabat, B. Laita, D. S. Dahan, R. D. Smith, H. Xu, L. Staszewski, J. Yamamoto, J. Ling, et al. Small Molecule Activator of the Human Epithelial Sodium Channel J. Biol. Chem., May 2, 2008; 283(18): 11981 - 11994. [Abstract] [Full Text] [PDF]

				M. Barann, I. Linden, S. Witten, and B. W. Urban Molecular Actions of Propofol on Human 5-HT3A Receptors: Enhancement as Well as Inhibition by Closely Related Phenol Derivatives Anesth. Analg., March 1, 2008; 106(3): 846 - 857. [Abstract] [Full Text] [PDF]

				J. H. Kloda and C. Czajkowski Agonist-, Antagonist-, and Benzodiazepine-Induced Structural Changes in the {alpha}1 Met113-Leu132 Region of the GABAA Receptor Mol. Pharmacol., February 1, 2007; 71(2): 483 - 493. [Abstract] [Full Text] [PDF]

				C. L. Padgett, A. P. Hanek, H. A. Lester, D. A. Dougherty, and S. C. R. Lummis Unnatural Amino Acid Mutagenesis of the GABAA Receptor Binding Site Residues Reveals a Novel Cation-{pi} Interaction between GABA and {beta}2Tyr97 J. Neurosci., January 24, 2007; 27(4): 886 - 892. [Abstract] [Full Text] [PDF]

				A. Keramidas, T. L. Kash, and N. L. Harrison The pre-M1 segment of the {alpha}1 subunit is a transduction element in the activation of the GABAA receptor J. Physiol., August 15, 2006; 575(1): 11 - 22. [Abstract] [Full Text] [PDF]

				D. Rotem, S. Steiner-Mordoch, and S. Schuldiner Identification of Tyrosine Residues Critical for the Function of an Ion-coupled Multidrug Transporter J. Biol. Chem., July 7, 2006; 281(27): 18715 - 18722. [Abstract] [Full Text] [PDF]

				R. Zhang, N. A. White, F. S. Soti, W. R. Kem, and T. K. Machu N-Terminal Domains in Mouse and Human 5-Hydroxytryptamine3A Receptors Confer Partial Agonist and Antagonist Properties to Benzylidene Analogs of Anabaseine J. Pharmacol. Exp. Ther., June 1, 2006; 317(3): 1276 - 1284. [Abstract] [Full Text] [PDF]

				M. Criado, J. Mulet, J. A. Bernal, S. Gerber, S. Sala, and F. Sala Mutations of a Conserved Lysine Residue in the N-Terminal Domain of {alpha}7 Nicotinic Receptors Affect Gating and Binding of Nicotinic Agonists Mol. Pharmacol., December 1, 2005; 68(6): 1669 - 1677. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help