TY - JOUR
T1 - The structural basis of water permeation and proton exclusion in aquaporins (Review)
AU - Fu, Dax
AU - Lu, Min
N1 - Funding Information:
This work was supported by a National Institute of Health grant RO1 GM65137 (to D. Fu). BNL is managed by Brookhaven Science Associates for the US Department of Energy.
PY - 2007/9
Y1 - 2007/9
N2 - Aquaporins (AQPs) represent a ubiquitous class of integral membrane proteins that play critical roles in cellular osmoregulations in microbes, plants and mammals. AQPs primarily function as water-conducting channels, whereas members of a sub-class of AQPs, termed aquaglyceroporins, are permeable to small neutral solutes such as glycerol. While AQPs facilitate transmembrane permeation of water and/or small neutral solutes, they preclude the conduction of protons. Consequently, openings of AQP channels allow rapid water diffusion down an osmotic gradient without dissipating electrochemical potentials. Molecular structures of AQPs portray unique features that define the two central functions of AQP channels: effective water permeation and strict proton exclusion. This review describes AQP structures known to date and discusses the mechanisms underlying water permeation, proton exclusion and water permeability regulation.
AB - Aquaporins (AQPs) represent a ubiquitous class of integral membrane proteins that play critical roles in cellular osmoregulations in microbes, plants and mammals. AQPs primarily function as water-conducting channels, whereas members of a sub-class of AQPs, termed aquaglyceroporins, are permeable to small neutral solutes such as glycerol. While AQPs facilitate transmembrane permeation of water and/or small neutral solutes, they preclude the conduction of protons. Consequently, openings of AQP channels allow rapid water diffusion down an osmotic gradient without dissipating electrochemical potentials. Molecular structures of AQPs portray unique features that define the two central functions of AQP channels: effective water permeation and strict proton exclusion. This review describes AQP structures known to date and discusses the mechanisms underlying water permeation, proton exclusion and water permeability regulation.
KW - Aquaporin
KW - Mechanisms underlying water permeation
KW - Membrane permeability
KW - Membrane protein
KW - Protein structure
UR - http://www.scopus.com/inward/record.url?scp=34548060640&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34548060640&partnerID=8YFLogxK
U2 - 10.1080/09687680701446965
DO - 10.1080/09687680701446965
M3 - Review article
C2 - 17710641
AN - SCOPUS:34548060640
SN - 0968-7688
VL - 24
SP - 366
EP - 374
JO - Molecular Membrane Biology
JF - Molecular Membrane Biology
IS - 5-6
ER -