Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Proc Natl Acad Sci U S A
2005 Feb 08;1026:2192-7. doi: 10.1073/pnas.0409232102.
Show Gene links
Show Anatomy links
Conversion of aquaporin 6 from an anion channel to a water-selective channel by a single amino acid substitution.
Liu K
,
Kozono D
,
Kato Y
,
Agre P
,
Hazama A
,
Yasui M
.
???displayArticle.abstract???
Aquaporin (AQP) 6 belongs to the aquaporin water channel family. Unlike other aquaporins, AQP6 functions not as a water channel but as an anion-selective channel. Single-channel analyses have shown AQP6 to flicker rapidly between closed and open status. The atomic structure of AQP1 and amino acid sequence alignments of the mammalian aquaporins reveal two well conserved glycine residues: Gly-57 in transmembrane helix (TM) 2 and Gly-173 in TM5 reside at the contact point where the two helices cross in human AQP1. Uniquely, all known mammalian orthologs of AQP6 have an asparagine residue (Asn-60) at the position corresponding to Gly-57. Here we show that a single residue substitution (N60G in rat AQP6) totally eliminates the anion permeability of AQP6 when expressed in Xenopus oocytes, but the N60G oocytes exhibit significantly higher osmotic water permeability under basal conditions. Replacement of the glycine at this site in AQP0, AQP1, and AQP2 blocked expression of the mutants at the oocyteplasma membrane. We propose that the asparagine residue at the contact point between TM2 and TM5 in AQP6 may function as a teeter board needed for rapid structural oscillations during anion permeation.
Agre,
Aquaporin water channels (Nobel Lecture).
2004, Pubmed
Agre,
Aquaporin water channels (Nobel Lecture).
2004,
Pubmed
Agre,
Aquaporin water channels--from atomic structure to clinical medicine.
2002,
Pubmed
Burykin,
On the origin of the electrostatic barrier for proton transport in aquaporin.
2004,
Pubmed
Chakrabarti,
Structural determinants of proton blockage in aquaporins.
2004,
Pubmed
de Groot,
Water permeation across biological membranes: mechanism and dynamics of aquaporin-1 and GlpF.
2001,
Pubmed
Harries,
The channel architecture of aquaporin 0 at a 2.2-A resolution.
2004,
Pubmed
Hazama,
Ion permeation of AQP6 water channel protein. Single channel recordings after Hg2+ activation.
2002,
Pubmed
,
Xenbase
Ikeda,
Characterization of aquaporin-6 as a nitrate channel in mammalian cells. Requirement of pore-lining residue threonine 63.
2002,
Pubmed
,
Xenbase
Ilan,
The mechanism of proton exclusion in aquaporin channels.
2004,
Pubmed
Kozono,
Aquaporin water channels: atomic structure molecular dynamics meet clinical medicine.
2002,
Pubmed
Ma,
Cloning of a novel rat kidney cDNA homologous to CHIP28 and WCH-CD water channels.
1993,
Pubmed
Ma,
Closely spaced tandem arrangement of AQP2, AQP5, and AQP6 genes in a 27-kilobase segment at chromosome locus 12q13.
1997,
Pubmed
MacKinnon,
Potassium channels and the atomic basis of selective ion conduction (Nobel Lecture).
2004,
Pubmed
Murata,
Structural determinants of water permeation through aquaporin-1.
2000,
Pubmed
Preston,
Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein.
1992,
Pubmed
,
Xenbase
Schneider,
Thermostability of membrane protein helix-helix interaction elucidated by statistical analysis.
2002,
Pubmed
Smith,
Cystic fibrosis transmembrane conductance regulator. Physical basis for lyotropic anion selectivity patterns.
1999,
Pubmed
,
Xenbase
Stroud,
Selectivity and conductance among the glycerol and water conducting aquaporin family of channels.
2003,
Pubmed
Sui,
Structural basis of water-specific transport through the AQP1 water channel.
,
Pubmed
Tajkhorshid,
Control of the selectivity of the aquaporin water channel family by global orientational tuning.
2002,
Pubmed
Tsunoda,
Aquaporin-1, nothing but a water channel.
2004,
Pubmed
,
Xenbase
Warshel,
Inverting the selectivity of aquaporin 6: gating versus direct electrostatic interaction.
2005,
Pubmed
Yasui,
Rapid gating and anion permeability of an intracellular aquaporin.
1999,
Pubmed
,
Xenbase
Yasui,
Aquaporin-6: An intracellular vesicle water channel protein in renal epithelia.
1999,
Pubmed
Yool,
Forskolin stimulation of water and cation permeability in aquaporin 1 water channels.
1996,
Pubmed
,
Xenbase
