title: New mammalian chloride channel identified by expression cloning.
abstract: Ion channels selectively permeable to chloride ions regulate cell functions as diverse as excitability and control of cell volume. Using expression cloning techniques, a complementary DNA from an epithelial cell line has been isolated, sequenced and its putative structure examined by site-directed mutagenesis. This cDNA, encoding a 235-amino-acid protein, gave rise to a chloride-selective outward current when expressed in Xenopus oocytes. The expressed, outwardly rectifying chloride current was calcium-insensitive and was blocked by nucleotides applied to the cell surface. Mutation of a putative nucleotide-binding site resulted in loss of nucleotide block but incurred dependence on extracellular calcium concentration. The unusual sequence of this putative channel protein suggests a new class of ion channels not related to other previously cloned chloride channels.
authors.affiliation: Department of Pharmacology, Mayo Foundation, Rochester, Minnesota 55905.
authors.forename: M
authors.initials: M
authors.lastname: Paulmichl
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: K
authors.initials: K
authors.lastname: Wickman
authors.forename: M
authors.initials: M
authors.lastname: Ackerman
authors.forename: E
authors.initials: E
authors.lastname: Peralta
authors.forename: D
authors.initials: D
authors.lastname: Clapham
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D018118:Chloride Channels; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004285:Dogs; D004553:Electric Conductivity; D015870:Gene Expression; D007668:Kidney; D007700:Kinetics; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009865:Oocytes / Q000378:metabolism; D010957:Plasmids; D014162:Transfection; D014982:Xenopus laevis
chemical_list: D018118:Chloride Channels; D008565:Membrane Proteins; D004247:DNA