title: Cloning and identification of a new member of water channel (AQP10) as an aquaglyceroporin.
abstract: Recently, a new member of aquaporins was reported as AQP10 [Biochem. Biophys. Res. Commun. 287 (2001) 814], which is incompletely spliced to lose the sixth transmembrane domain and has poor water and no glycerol/urea permeabilities. Independently, we identified a similar clone in human. Our AQP10 consists of 301 amino acids with a highly conserved sixth transmembrane domain. AQP10 has higher identity with aquaglyceroporins (50% with AQP9, 48% with AQP3, 42% with AQP7) and lower identity with other aquaporins (32% with AQP1 and AQP8). AQP10 is expressed only in the small intestine with (approximately 2 kb). RNase protection assay revealed the absence of the unspliced form, supporting the authenticity of our clone. When expressed in Xenopus oocytes, AQP10 stimulated osmotic water permeability sixfold in a mercury-sensitive manner. Glycerol and urea uptakes were also stimulated, while adenine uptake was not. The genome structure of AQP10 is similar to those of other aquaglyceroporins (AQP3, AQP7, AQP9) with six exons. We conclude that AQP10 represents a new member of aquaglyceroporins functionally as well as structurally.
authors.affiliation: Department of Pharmacology, Jichi Medical School, Minamikawachi, Kawachi, Tochigi 329-0498, Japan. kishiba@jichi.ac.jp
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ishibashi
authors.forename: Tomonori
authors.initials: T
authors.lastname: Morinaga
authors.forename: Michio
authors.initials: M
authors.lastname: Kuwahara
authors.forename: Sei
authors.initials: S
authors.lastname: Sasaki
authors.forename: Masashi
authors.initials: M
authors.lastname: Imai
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020346:Aquaporins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D006801:Humans; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D016366:Open Reading Frames; D012326:RNA Splicing; D016415:Sequence Alignment; D014018:Tissue Distribution; D014981:Xenopus
chemical_list: C438667:AQP10 protein, human; D020346:Aquaporins