Elimination of the slow gating of C1C-0 chloride channel by a point mutation

Yu Wen Lin, Chia Wei Lin, Tsung-Yu Chen

Research output: Contribution to journalArticle

77 Scopus citations

Abstract

The inactivation of the C1C-0 chloride channel is very temperature sensitive and is greatly facilitated by the binding of a zinc ion (Zn2+) from the extracellular side, leading to a Zn2+-induced current inhibition. To further explore the relation of Zn2+ inhibition and the C1C-0 inactivation, we mutated all 12 cysteine amino acids in the channel and assayed the effect of Zn2+ on these mutants. With this approach, we found that C212 appears to be important for the sensitivity of the Zn2+ inhibition. Upon mutating C212 to serine or alanine, the inactivation of the channel in macroscopic current recordings disappears and the channel does not show detectable inactivation events at the single-channel level. At the same time, the channel's sensitivity to Zn2+ inhibition is also greatly reduced. The other two cysteine mutants, C213G and C480S, as well as a previously identified mutant, S123T, also affect the inactivation of the channel to some degree, but the temperature-dependent inactivation process is still present, likewise the high sensitivity of the Zn2+ inhibition. These results further support the assertion that the inhibition of Zn2+ on C1C-0 is indeed due to an effect on the inactivation of the channel. The absence of inactivation in C212S mutants may provide a better defined system to study the fast gating and the ion permeation of C1C-0.

Original languageEnglish (US)
Pages (from-to)1-12
Number of pages12
JournalJournal of General Physiology
Volume114
Issue number1
StatePublished - Jul 1999
Externally publishedYes

Keywords

  • C1C-0
  • Cysteine mutagenesis
  • Slow gating
  • Zn inhibition

ASJC Scopus subject areas

  • Physiology

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