Structure and function of CLC channels

Research output: Contribution to journalArticle

91 Citations (Scopus)

Abstract

The CLC family comprises a group of integral membrane proteins whose major action is to translocate chloride (Cl-) ions across the cell membranes. Recently, the structures of CLC orthologues from two bacterial species, Salmonella typhimurium and Escherichia coli, were solved, providing the first framework for understanding the operating mechanisms of these molecules. However, most of the previous mechanistic understanding of CLC channels came from electrophysiological studies of a branch of the channel family, the muscle-type CLC channels in vertebrate species. These vertebrate CLC channels were predicted to contain two identical but independent pores, and this hypothesis was confirmed by the solved bacterial CLC structures. The opening and closing of the vertebrate CLC channels are also known to couple to the permeant ions via their binding sites in the ion-permeation pathway. The bacterial CLC structures can probably serve as a structural model to explain the gating-permeation coupling mechanism. However, the CLC-ec1 protein in E. coli was most recently shown to be a Cl--H+ antiporter, but not an ion channel. The molecular basis to explain the difference between vertebrate and bacterial CLCs, especially the distinction between an ion channel and a transporter, remains a challenge in the structure/function studies for the CLC family.

Original languageEnglish (US)
Pages (from-to)809-839
Number of pages31
JournalAnnual Review of Physiology
Volume67
DOIs
StatePublished - 2005

Fingerprint

Vertebrates
Bacterial Structures
Ions
Ion Channels
Chlorides
Antiporters
Structural Models
Salmonella typhimurium
Membrane Proteins
Binding Sites
Cell Membrane
Escherichia coli
Muscles

Keywords

  • Chloride channel
  • CLC family
  • Gating
  • Permeation
  • Transporter

ASJC Scopus subject areas

  • Physiology

Cite this

Structure and function of CLC channels. / Chen, Tsung-Yu.

In: Annual Review of Physiology, Vol. 67, 2005, p. 809-839.

Research output: Contribution to journalArticle

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