title: Two highly homologous members of the ClC chloride channel family in both rat and human kidney.
abstract: We have cloned two closely related putative Cl- channels from both rat kidney (designated rClC-K1 and rClC-K2) and human kidney (hClC-Ka and hClC-Kb) by sequence homology to the ClC family of voltage-gated Cl- channels. While rClC-K1 is nearly identical to ClC-K1, a channel recently isolated by a similar strategy, rClC-K2 is 80% identical to rClC-K1 and is encoded by a different gene. hClC-Ka and hClC-Kb show approximately 90% identity, while being approximately 80% identical to the rat proteins. All ClC-K gene products are expressed predominantly in the kidney. While rClC-K1 is expressed strongly in the cortical thick ascending limb and the distal convoluted tubule, with minor expression in the S3 segment of the proximal tubule and the cortical collecting tubule, rClC-K2 is expressed in all segments of the nephron examined, including the glomerulus. Since they are related more closely to each other than to the rat proteins, hClC-Ka and hClC-Kb cannot be regarded as strict homologs of rClC-K1 or rClC-K2. After injection of ClC-K cRNAs into oocytes, corresponding proteins were made and glycosylated, though no additional Cl- currents were detectable. Glycosylation occurs between domains D8 and D9, leading to a revision of the transmembrane topology model for ClC channels.
authors.affiliation: Centre for Molecular Neurobiology (ZMNH), Hamburg University, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Kieferle
authors.forename: P
authors.initials: P
authors.lastname: Fong
authors.forename: M
authors.initials: M
authors.lastname: Bens
authors.forename: A
authors.initials: A
authors.lastname: Vandewalle
authors.forename: T J
authors.initials: TJ
authors.lastname: Jentsch
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018118:Chloride Channels / Q000737:chemistry / Q000378:metabolism*; D003001:Cloning, Molecular; D004247:DNA; D006031:Glycosylation; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
chemical_list: D018118:Chloride Channels; D004247:DNA