Probing the major skeletal muscle chloride channel with Zn2+ and other sulfhydryl-reactive compounds

Lothar L. Kürz*, Susanne Wagner, Alfred L. George, Reinhardt Rüdel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

The sensitivity of the human skeletal muscle Cl- channel, hClC-1, towards various sulfhydryl-reactive agents was tested with the channel expressed in Xenopus oocytes and in human embryonic kidney cells. External but not internal Zn2+, at 1 mM, substantially reduced the current without affecting activation parameters. External Cd2+ and Hg2+ as well as organic mercurial compounds reduced the Cl- currents to a similar degree. With the mutant channel hClC-1 D136G, presumed to have a defective voltage sensor, external Zn2+ also reduced the current without effect on the altered gating. These findings suggest that hClC-1 contains cysteine residues near the extracellular face that may directly influence ion conduction. Since Zn2+ can also bind to histidine side chains, we tested the effect of compounds with either more cysteine- or more histidine-specificity. The results confirm the involvement of cysteine(s) in the observed effects but do not exclude the involvement of histidine(s).

Original languageEnglish (US)
Pages (from-to)357-363
Number of pages7
JournalPflugers Archiv European Journal of Physiology
Volume433
Issue number3
DOIs
StatePublished - Dec 1996

Keywords

  • Chloride channels
  • Membrane topology
  • Skeletal muscle
  • Sulfhydryl reagents
  • Zinc ions

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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