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

J. Biol. Chem., Vol. 279, Issue 44, 45399-45407, October 29, 2004

This Article Full Text Full Text (PDF) All Versions of this Article: 279/44/45399    most recent M408410200v1 Submit a Letter to Editor 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 PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Li, Y. Articles by Shapiro, M. S. Search for Related Content PubMed PubMed Citation Articles by Li, Y. Articles by Shapiro, M. S. Social Bookmarking                      What's this?

Dual Phosphorylations Underlie Modulation of Unitary KCNQ K⁺ Channels by Src Tyrosine Kinase^*

Yang Li, Paul Langlais, Nikita Gamper, Feng Liu, and Mark S. Shapiro¶

From the Departments of Physiology and Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229

Src tyrosine kinase suppresses KCNQ (M-type) K⁺ channels in a subunit-specific manner representing a mode of modulation distinct from that involving G protein-coupled receptors. We probed the molecular and biophysical mechanisms of this modulation using mutagenesis, biochemistry, and both whole-cell and single channel modes of patch clamp recording. Immunoprecipitation assays showed that Src associates with KCNQ2–5 subunits but phosphorylates only KCNQ3–5. Using KCNQ3 as a background, we found that mutation of a tyrosine in the amino terminus (Tyr-67) or one in the carboxyl terminus (Tyr-349) abolished Src-dependent modulation of heterologously expressed KCNQ2/3 heteromultimers. The tyrosine phosphorylation was much weaker for either the KCNQ3-Y67F or KCNQ3-Y349F mutants and wholly absent in the KCNQ3-Y67F/Y349F double mutant. Biotinylation assays showed that Src activity does not alter the membrane abundance of channels in the plasma membrane. In recordings from cell-attached patches containing a single KCNQ2/3 channel, we found that Src inhibits the open probability of the channels. Kinetic analysis was consistent with the channels having two discrete open times and three closed times. Src activity reduced the durations of the longest open time and lengthened the longest closed time of the channels. The implications for the mechanisms of channel regulation by the dual phosphorylations on both channel termini are discussed.

Received for publication, July 26, 2004 , and in revised form, August 2, 2004.

^* This work was supported by National Institutes of Health Grants RO1 NS43394 (to M. S. S.) and RO1 DK52933 (to F. L.), by an American Heart Association-Texas Affiliate beginning grant-in-aid (to M. S. S.) and postdoctoral fellowship (to N. G.), and by the Epilepsy Foundation (to M. S. S.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

^¶ To whom correspondence should be addressed: Dept. of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229. Tel.: 210-567-4328; Fax: 210-567-4410; E-mail: shapirom{at}uthscsa.edu.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				Z. Jia, J. Bei, L. Rodat-Despoix, B. Liu, Q. Jia, P. Delmas, and H. Zhang NGF Inhibits M/KCNQ Currents and Selectively Alters Neuronal Excitability in Subsets of Sympathetic Neurons Depending on their M/KCNQ Current Background J. Gen. Physiol., June 1, 2008; 131(6): 575 - 587. [Abstract] [Full Text] [PDF]

				Y. Haitin and B. Attali The C-terminus of Kv7 channels: a multifunctional module J. Physiol., April 1, 2008; 586(7): 1803 - 1810. [Abstract] [Full Text] [PDF]

				M. V. Soldovieri, M. R. Cilio, F. Miceli, G. Bellini, E. Miraglia del Giudice, P. Castaldo, C. C. Hernandez, M. S. Shapiro, A. Pascotto, L. Annunziato, et al. Atypical Gating Of M-Type Potassium Channels Conferred by Mutations in Uncharged Residues in the S4 Region of KCNQ2 Causing Benign Familial Neonatal Convulsions J. Neurosci., May 2, 2007; 27(18): 4919 - 4928. [Abstract] [Full Text] [PDF]

				T. S. Surti, L. Huang, Y. N. Jan, L. Y. Jan, and E. C. Cooper Identification by mass spectrometry and functional characterization of two phosphorylation sites of KCNQ2/KCNQ3 channels PNAS, December 6, 2005; 102(49): 17828 - 17833. [Abstract] [Full Text] [PDF]

				A. F. Lau c-Src: Bridging the Gap Between Phosphorylation- and Acidification-Induced Gap Junction Channel Closure Sci. Signal., July 5, 2005; 2005(291): pe33 - pe33. [Abstract] [Full Text] [PDF]

				C. A. Ahern, J.-F. Zhang, M. J. Wookalis, and R. Horn Modulation of the Cardiac Sodium Channel NaV1.5 by Fyn, a Src Family Tyrosine Kinase Circ. Res., May 13, 2005; 96(9): 991 - 998. [Abstract] [Full Text] [PDF]