title: Cloning of a novel rat kidney cDNA homologous to CHIP28 and WCH-CD water channels.
abstract: Two kidney water channels have been identified: CHIP28 in proximal tubule and thin descending limb, and WCH-CD in collecting duct apical membrane. An homologous cDNA (WCH3) was obtained from rat kidney and found to encode a 276 amino acid, 29 kDa protein with 39% amino acid identity to rat CHIP28, 50% to WCH-CD and 49% to MIP26. The WCH3 transcript of 2.5 kb was expressed exclusively in kidney and was upregulated in dehydrated rats. Cell-free translation produced an approximately 28 kDa protein. Analysis of the predicted amino acid sequence indicated a hydrophobic protein with 4-6 membrane-spanning domains, with one N-linked glycosylation site, two conserved NPA boxes common to MIP26 family proteins, and conserved residue C189 common to water channels. WCH3 is a new member of the MIP26 family of channel-forming proteins in mammalian kidney.
authors.affiliation: Department of Medicine, University of California, San Francisco 94143-0532.
authors.forename: T
authors.initials: T
authors.lastname: Ma
authors.forename: A
authors.initials: A
authors.lastname: Frigeri
authors.forename: W
authors.initials: W
authors.lastname: Skach
authors.forename: A S
authors.initials: AS
authors.lastname: Verkman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051398:Aquaporin 1; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D017931:DNA Primers; D018076:DNA, Complementary / Q000378:metabolism*; D015723:Gene Library; D007473:Ion Channels / Q000096:biosynthesis*; D007668:Kidney / Q000378:metabolism*; D007672:Kidney Cortex / Q000378:metabolism; D007679:Kidney Medulla / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000737:chemistry; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D011487:Protein Conformation; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017386:Sequence Homology, Amino Acid
chemical_list: C496022:Aqp1 protein, rat; C496025:Aqp2 protein, rat; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins; D017931:DNA Primers; D018076:DNA, Complementary; D007473:Ion Channels; D008565:Membrane Proteins; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D051398:Aquaporin 1