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J. Biol. Chem., Vol. 281, Issue 50, 38573-38581, December 15, 2006

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 281/50/38573    most recent M604769200v1 Alert me when this article is cited 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 Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kim, H.-J. Articles by Park, C.-S. Search for Related Content PubMed PubMed Citation Articles by Kim, H.-J. Articles by Park, C.-S. Social Bookmarking                      What's this?

Hydrophobic Interface between Two Regulators of K⁺ Conductance Domains Critical for Calcium-dependent Activation of Large Conductance Ca²⁺-activated K⁺ Channels^*

Hyun-Ju Kim, Hyun-Ho Lim, Seong-Hwan Rho, Soo Hyun Eom, and Chul-Seung Park¹

From the Department of Life Science and Research Center for Biomolecular Nanotechnology, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea

It has been suggested that the large conductance Ca²+-activated K⁺ channel contains one or more domains known as regulators of K⁺ conductance (RCK) in its cytosolic C terminus. Here, we show that the second RCK domain (RCK2) is functionally important and that it forms a heterodimer with RCK1 via a hydrophobic interface. Mutant channels lacking RCK2 are nonfunctional despite their tetramerization and surface expression. The hydrophobic residues that are expected to form an interface between RCK1 and RCK2, based on the crystal structure of the bacterial MthK channel, are well conserved, and the interactions of these residues were confirmed by mutant cycle analysis. The hydrophobic interaction appears to be critical for the Ca²⁺-dependent gating of the large conductance Ca²⁺-activated K⁺ channel.

Received for publication, May 18, 2006 , and in revised form, September 29, 2006.

^* This research was supported by research grants from the Korea Research Foundation (KRF-2005-015-C00398) and the Korea Science and Engineering Foundation (R01-2006-000-10880-0) (to C.-S. P.). 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.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. 1-3.

¹ To whom correspondence should be addressed: Dept. of Life Science, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, Korea. Tel.: 82-62-970-2489; Fax: 82-62-970-2484; E-mail: cspark{at}gist.ac.kr.

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