PMID- 10647010
OWN - NLM
STAT- MEDLINE
DCOM- 20000203
LR  - 20151119
IS  - 0028-0836 (Print)
IS  - 0028-0836 (Linking)
VI  - 402
IP  - 6758
DP  - 1999 Nov 11
TI  - Rapid gating and anion permeability of an intracellular aquaporin.
PG  - 184-7
AB  - Aquaporin (AQP) water-channel proteins are freely permeated by water but not by
      ions or charged solutes. Although mammalian aquaporins were believed to be
      located in plasma membranes, rat AQP6 is restricted to intracellular vesicles in 
      renal epithelia. Here we show that AQP6 is functionally distinct from other known
      aquaporins. When expressed in Xenopus laevis oocytes, AQP6 exhibits low basal
      water permeability; however, when treated with the known water channel inhibitor,
      Hg2+, the water permeability of AQP6 oocytes rapidly rises up to tenfold and is
      accompanied by ion conductance. AQP6 colocalizes with H+-ATPase in intracellular 
      vesicles of acid-secreting alpha-intercalated cells in renal collecting duct. At 
      pH less than 5.5, anion conductance is rapidly and reversibly activated in AQP6
      oocytes. Site-directed mutation of lysine to glutamate at position 72 in the
      cytoplasmic mouth of the pore changes the cation/anion selectivity, but leaves
      low pH activation intact. Our results demonstrate unusual biophysical properties 
      of an aquaporin, and indicate that anion-channel function may now be explored in 
      a protein with known structure.
FAU - Yasui, M
AU  - Yasui M
AD  - Department of Biological Chemistry, Johns Hopkins University School of Medicine, 
      Baltimore, MD 21205, USA.
FAU - Hazama, A
AU  - Hazama A
FAU - Kwon, T H
AU  - Kwon TH
FAU - Nielsen, S
AU  - Nielsen S
FAU - Guggino, W B
AU  - Guggino WB
FAU - Agre, P
AU  - Agre P
LA  - eng
SI  - GENBANK/AF083879
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - Nature
JT  - Nature
JID - 0410462
RN  - 0 (Anions)
RN  - 0 (Aqp2 protein, rat)
RN  - 0 (Aqp6 protein, rat)
RN  - 0 (Aquaporin 2)
RN  - 0 (Aquaporin 6)
RN  - 0 (Aquaporins)
RN  - 0 (Recombinant Proteins)
RN  - 059QF0KO0R (Water)
RN  - 451W47IQ8X (Sodium Chloride)
RN  - FXS1BY2PGL (Mercury)
SB  - IM
MH  - Animals
MH  - Anions/metabolism
MH  - Aquaporin 2
MH  - Aquaporin 6
MH  - Aquaporins/genetics/*metabolism/ultrastructure
MH  - Cell Membrane Permeability
MH  - Hydrogen-Ion Concentration
MH  - *Ion Channel Gating/drug effects
MH  - Membrane Potentials
MH  - Mercury/pharmacology
MH  - Molecular Sequence Data
MH  - Mutagenesis, Site-Directed
MH  - Rats
MH  - Recombinant Proteins/metabolism
MH  - Sodium Chloride/metabolism
MH  - Water/metabolism
MH  - Xenopus laevis
EDAT- 2000/01/26 09:00
MHDA- 2001/03/23 10:01
CRDT- 2000/01/26 09:00
PHST- 2000/01/26 09:00 [pubmed]
PHST- 2001/03/23 10:01 [medline]
PHST- 2000/01/26 09:00 [entrez]
AID - 10.1038/46045 [doi]
PST - ppublish
SO  - Nature. 1999 Nov 11;402(6758):184-7. doi: 10.1038/46045.