Movement of hClC-1 C-termini during common gating and limits on their cytoplasmic location

Linlin Ma, Grigori Y. Rychkov, Ekaterina A. Bykova, Jie Zheng, Allan H. Bretag

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Functionally, the dimeric human skeletal muscle chloride channel hClC-1 is characterized by two distinctive gating processes, fast (protopore) gating and slow (common) gating. Of these, common gating is poorly understood, but extensive conformational rearrangement is suspected. To examine this possibility, we used FRET (fluorescence resonance energy transfer) and assessed the effects of manipulating the common-gating process. Closure of the common gate was accompanied by a separation of the C-termini, whereas, with opening, the C-termini approached each other more closely. These movements were considerably smaller than those seen in ClC-0. To estimate the C-terminus depth within the cytoplasm we constructed a pair of split hClC-1 fragments tagged extracellularly and intracellularly respectively. These not only combined appropriately to rescue channel function, but we detected positive FRET between them. This restricts the C-termini of hClC-1 to a position close to its membrane-resident domain. From mutants in which fast or common gating were affected, FRET revealed a close linkage between the two gating processes with the carboxyl group of Glu232 apparently acting as the final effector for both.

Original languageEnglish (US)
Pages (from-to)415-428
Number of pages14
JournalBiochemical Journal
Volume436
Issue number2
DOIs
StatePublished - Jun 1 2011

Keywords

  • C-terminus
  • Common gating
  • Conformation change
  • Cytoplasmic domain
  • Fluorescence resonance energy transfer (FRET)
  • Human skeletal muscle chloride channel (hClC-1)

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

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