We are seeing patients in-person and through Video Visits. Learn more about how we’re keeping you safe and please review our updated visitor policy. Please also consider supporting Weill Cornell Medicine’s efforts to support our front-line workers.
Department of Anesthesiology

You are here

Molecular determinants of differential pore blocking of kidney CLC-K chloride channels.

TitleMolecular determinants of differential pore blocking of kidney CLC-K chloride channels.
Publication TypeJournal Article
Year of Publication2004
AuthorsPicollo A, Liantonio A, Didonna MPaola, Elia L, Camerino DConte, Pusch M
JournalEMBO Rep
Volume5
Issue6
Pagination584-9
Date Published2004 Jun
ISSN1469-221X
Keywords2-Methyl-4-chlorophenoxyacetic Acid, 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid, Amino Acid Motifs, Anion Transport Proteins, Binding Sites, Chloride Channels, Dose-Response Relationship, Drug, Humans, Membrane Proteins, Patch-Clamp Techniques, Point Mutation, Protein Structure, Tertiary
Abstract

The highly homologous Cl(-) channels CLC-Ka and CLC-Kb are important for water and salt conservation in the kidney and for the production of endolymph in the inner ear. Mutations in CLC-Kb lead to Bartter's syndrome and mutations in the small CLC-K subunit barttin lead to Bartter's syndrome and deafness. Here we show that CLC-Ka is blocked by the recently identified blocker 2-(p-chlorophenoxy)-3-phenylpropionic acid of the rat channel CLC-K1 with an apparent K(D) approximately 80 microM. We also found that DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid), a generic Cl(-) channel blocker, inhibits CLC-Ka (K(D) approximately 90 microM). Surprisingly, the highly homologous channel CLC-Kb is fivefold to sixfold less sensitive to both compounds. Guided by the crystal structure of bacterial CLC proteins, we identify two amino acids, N68/D68 and G72/E72, in CLC-Ka and CLC-Kb, respectively, that are responsible for the differential drug sensitivity. Both residues expose their side chains in the extracellular pore mouth, delineating the probable drug binding site. These novel CLC-K channel blockers are promising lead compounds for the development of new diuretic drugs.

DOI10.1038/sj.embor.7400169
Alternate JournalEMBO Rep.
PubMed ID15167890
PubMed Central IDPMC1299079