HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Services Email this article to a friend Similar articles in this journal 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 Google Scholar Google Scholar Articles by Salamone, F. N. Articles by Auerbach, A. Search for Related Content PubMed PubMed Citation Articles by Salamone, F. N. Articles by Auerbach, A.

A re-examination of adult mouse nicotinic acetylcholine receptor channel activation kinetics

Frank N. Salamone, Ming Zhou and Anthony Auerbach

During routine sequencing of our mouse muscle subunit acetylcholine receptor channel (AChR) cDNA clones, we detected a discrepancy with the GenBank database entry (accession X03986). At nucleotides 1305-7 (residue 433, in the M4 domain) the database lists GTC which encodes a valine, while our putative 'wild-type' cDNA had the nucleotides GCC, which encodes an alanine. No other sequence differences were found.

PCR amplification of genomic DNA confirmed that the BALB/C mouse subunit gene has a T nucleotide at position 1306, and, therefore, that the protein has a V at position 433 in the M4 segment.

In order to determine the functional consequences of this difference, either wild-type (V433) or mutant (A433) subunits were co-expressed in HEK cells with mouse , and subunits. Single-channel currents were recorded in cell-attached patches, and rate and equilibrium constants were estimated from open and closed durations obtained from a range of ACh concentrations. No significant differences were found between the activation rate constants or equilibrium constants of the V433 and A433 variants.

Kinetic modelling of V433 AChR suggests that the two transmitter binding sites have similar dissociation equilibrium constants for acetylcholine (~160 µM, in 142 mM extracellular KCl).

Diliganded AChRs occupy a closed state that has a lifetime of ~1 ms. The rate constants for entering and leaving this state do not vary with the ACh concentration.

The kinetics of a mutant AChR that causes a slow channel congenital myaesthenic syndrome, G153S, was re-examined. The properties of this mutant were similar with a V or an A at position 433.

This article has been cited by other articles:

				J. Militante, B.-W. Ma, G. Akk, and J. H. Steinbach Activation and Block of the Adult Muscle-Type Nicotinic Receptor by Physostigmine: Single-Channel Studies Mol. Pharmacol., September 1, 2008; 74(3): 764 - 776. [Abstract] [Full Text] [PDF]

				A. Jha, D. J. Cadugan, P. Purohit, and A. Auerbach Acetylcholine Receptor Gating at Extracellular Transmembrane Domain Interface: the Cys-Loop and M2 M3 Linker J. Gen. Physiol., November 26, 2007; 130(6): 547 - 558. [Abstract] [Full Text] [PDF]

				J. Corradi, G. Spitzmaul, M. J. De Rosa, M. Costabel, and C. Bouzat Role of Pairwise Interactions between M1 and M2 Domains of the Nicotinic Receptor in Channel Gating Biophys. J., January 1, 2007; 92(1): 76 - 86. [Abstract] [Full Text] [PDF]

				Y. Purohit and C. Grosman Estimating Binding Affinities of the Nicotinic Receptor for Low-efficacy Ligands Using Mixtures of Agonists and Two-dimensional Concentration-Response Relationships J. Gen. Physiol., May 30, 2006; 127(6): 719 - 735. [Abstract] [Full Text] [PDF]

				G. M. C. Lema and A. Auerbach Modes and models of GABAA receptor gating J. Physiol., April 1, 2006; 572(1): 183 - 200. [Abstract] [Full Text] [PDF]

				S. Schorge, S. Elenes, and D. Colquhoun Maximum likelihood fitting of single channel NMDA activity with a mechanism composed of independent dimers of subunits J. Physiol., December 1, 2005; 569(2): 395 - 418. [Abstract] [Full Text] [PDF]

				G. Akk, L. S Milescu, and M. Heckmann Activation of heteroliganded mouse muscle nicotinic receptors J. Physiol., April 15, 2005; 564(2): 359 - 376. [Abstract] [Full Text] [PDF]

				C. Shelley and D. Colquhoun A human congenital myasthenia-causing mutation ({varepsilon}L78P) of the muscle nicotinic acetylcholine receptor with unusual single channel properties J. Physiol., April 15, 2005; 564(2): 377 - 396. [Abstract] [Full Text] [PDF]

				G. Akk and J. H. Steinbach Galantamine Activates Muscle-Type Nicotinic Acetylcholine Receptors without Binding to the Acetylcholine-Binding Site J. Neurosci., February 23, 2005; 25(8): 1992 - 2001. [Abstract] [Full Text] [PDF]

				X.-M. Shen, K. Ohno, S. M. Sine, and A. G. Engel Subunit-specific contribution to agonist binding and channel gating revealed by inherited mutation in muscle acetylcholine receptor M3-M4 linker Brain, February 1, 2005; 128(2): 345 - 355. [Abstract] [Full Text] [PDF]

				V. Burzomato, M. Beato, P. J. Groot-Kormelink, D. Colquhoun, and L. G. Sivilotti Single-Channel Behavior of Heteromeric {alpha}1{beta} Glycine Receptors: An Attempt to Detect a Conformational Change before the Channel Opens J. Neurosci., December 1, 2004; 24(48): 10924 - 10940. [Abstract] [Full Text] [PDF]

				S. Chakrapani, T. D. Bailey, and A. Auerbach Gating Dynamics of the Acetylcholine Receptor Extracellular Domain J. Gen. Physiol., March 29, 2004; 123(4): 341 - 356. [Abstract] [Full Text] [PDF]

				M. Beato, P. J. Groot-Kormelink, D. Colquhoun, and L. G. Sivilotti The Activation Mechanism of {alpha}1 Homomeric Glycine Receptors J. Neurosci., January 28, 2004; 24(4): 895 - 906. [Abstract] [Full Text] [PDF]

				S. Chakrapani, T. D. Bailey, and A. Auerbach The Role of Loop 5 in Acetylcholine Receptor Channel Gating J. Gen. Physiol., October 27, 2003; 122(5): 521 - 539. [Abstract] [Full Text] [PDF]

				A. Auerbach Life at the Top: The Transition State of AChR Gating Sci. Signal., June 24, 2003; 2003(188): re11 - re11. [Abstract] [Full Text] [PDF]

				S. B. Hansen, Z. Radic', T. T. Talley, B. E. Molles, T. Deerinck, I. Tsigelny, and P. Taylor Tryptophan Fluorescence Reveals Conformational Changes in the Acetylcholine Binding Protein J. Biol. Chem., October 25, 2002; 277(44): 41299 - 41302. [Abstract] [Full Text] [PDF]

				S. M. Sine, X.-M. Shen, H.-L. Wang, K. Ohno, W.-Y. Lee, A. Tsujino, J. Brengmann, N. Bren, J. Vajsar, and A. G. Engel Naturally Occurring Mutations at the Acetylcholine Receptor Binding Site Independently Alter ACh Binding and Channel Gating J. Gen. Physiol., September 30, 2002; 120(4): 483 - 496. [Abstract] [Full Text] [PDF]

				M. J. De Rosa, D. Rayes, G. Spitzmaul, and C. Bouzat Nicotinic Receptor M3 Transmembrane Domain: Position 8' Contributes to Channel Gating Mol. Pharmacol., August 1, 2002; 62(2): 406 - 414. [Abstract] [Full Text] [PDF]

				C. Grosman and A. Auerbach The dissociation of acetylcholine from open nicotinic receptor channels PNAS, November 20, 2001; 98(24): 14102 - 14107. [Abstract] [Full Text] [PDF]

				L. Chen, H. Wang, S. Vicini, and R. W. Olsen The gamma -aminobutyric acid type A (GABAA) receptor-associated protein (GABARAP) promotes GABAA receptor clustering and modulates the channel kinetics PNAS, September 8, 2000; (2000) 190133497. [Abstract] [Full Text]

				M. Zhou, A. G. Engel, and A. Auerbach Serum choline activates mutant acetylcholine receptors that cause slow channel congenital myasthenic syndromes PNAS, August 31, 1999; 96(18): 10466 - 10471. [Abstract] [Full Text] [PDF]

				L. Chen, H. Wang, S. Vicini, and R. W. Olsen From the Cover: The gamma -aminobutyric acid type A (GABAA) receptor-associated protein (GABARAP) promotes GABAA receptor clustering and modulates the channel kinetics PNAS, October 10, 2000; 97(21): 11557 - 11562. [Abstract] [Full Text] [PDF]