The hidden cation-selective pore in ion-conducting aquaporin OsPIP2;4 from rice.

Ion-conducting aquaporins (icAQPs) transport ions as well as water. Although the molecular mechanism of how AQPs establish selective permeability for water molecules is well understood, the ion-transporting mechanism in icAQPs has not yet been fully elucidated. In this study, we investigated the molecular mechanism of cation transport in OsPIP2;4, an icAQP in rice, by homology modeling and the electrophysiological analysis using Xenopus laevis oocytes.

OsPIP2;4 aquaporin water channel primarily expressed in roots of rice mediates both water and nonselective Na and K conductance.

Aquaporin (AQP)-dependent water transport across membranes is indispensable in plants. Recent evidence shows that several AQPs, including plasma membrane intrinsic proteins (PIPs), facilitate the electrogenic transport of ions as well as water transport and are referred to as ion-conducting aquaporins (icAQPs). The present study attempted to identify icAQPs that exhibit cation transport activity among PIPs from rice.

Distinct Functions of the Atypical Terminal Hydrophilic Domain of the HKT Transporter in the Liverwort Marchantia polymorpha.

K+/Na+ homeostasis is important for land plants, particularly under salt stress. In this study, the structure and ion transport properties of the high-affinity K+ transporter (HKT) of the liverwort Marchantia polymorpha were investigated. Only one HKT gene, MpHKT1, was identified in the genome of M.

A Survey of Barley PIP Aquaporin Ionic Conductance Reveals Ca-Sensitive Na and K Conductance.

Some plasma membrane intrinsic protein (PIP) aquaporins can facilitate ion transport. Here we report that one of the 12 barley PIPs (PIP1 and PIP2) tested, , facilitated cation transport when expressed in oocytes. -associated ion currents were detected with Na and K, but not Cs, Rb, or Li, and was inhibited by Ba, Ca, and Cd and to a lesser extent Mg, which also interacted with Ca.