TY  - JOUR
A1  - Wood, C. C.
A1  - Poree, Fabien
A1  - Dreyer, Ingo
A1  - Koehler, G. J.
A1  - Udvardi, M. K.
T1  - Mechanisms of ammonium transport, accumulation, and retention in ooyctes and yeast cells expressing Arabidopsis AtAMT1; 1
N2  - Ammonium is a primary source of N for plants, so knowing how it is transported, stored, and assimilated in plant cells is important for rational approaches to optimise N-use in agriculture. Electrophysiological studies of Arabidopsis AtAMT1;1 expressed in oocytes revealed passive, Delta psi-driven transport of NH4+ through this protein. Expression of AtAMT1;1 in a novel yeast mutant defective in endogenous ammonium transport and vacuolar acidification supported the above mechanism for AtAMT1;1 and revealed a central role for acid vacuoles in storage and retention of ammonia in cells. These results highlight the mechanistic differences between plant AMT proteins and related transporters in bacteria and animal cells, and suggest novel strategies to enhance nitrogen use efficiency in agriculture. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved
Y1  - 2006
UR  - http://www.sciencedirect.com/science/article/pii/S0014579306007332
U6  - https://doi.org/10.1016/j.febslet.2006.06.026
ER  - 
TY  - JOUR
A1  - Johansson, Ingela
A1  - Wulfetange, Klaas
A1  - Poree, Fabien
A1  - Michard, Erwan
A1  - Gajdanowicz, Pawel
A1  - Lacombe, Benoit
A1  - Sentenac, Herve
A1  - Thibaud, Jean-Baptiste
A1  - Müller-Röber, Bernd
A1  - Blatt, Michael R.
A1  - Dreyer, Ingo
T1  - External K+ modulates the activity of the Arabidopsis potassium channel SKOR via an unusual mechanism
N2  - Plant outward-rectifying K+ channels mediate K+ efflux from guard cells during stomatal closure and from root cells into the xylem for root-shoot allocation of potassium (K). Intriguingly, the gating of these channels depends on the extracellular K+ concentration, although the ions carrying the current are derived from inside the cell. This K+ dependence confers a sensitivity to the extracellular K+ concentration ([K+]) that ensures that the channels mediate K+ efflux only, regardless of the [K+] prevailing outside. We investigated the mechanism of K+-dependent gating of the K+ channel SKOR of Arabidopsis by site-directed mutagenesis. Mutations affecting the intrinsic K+ dependence of gating were found to cluster in the pore and within the sixth transmembrane helix (S6), identifying an 'S6 gating domain' deep within the membrane. Mapping the SKOR sequence to the crystal structure of the voltage-dependent K+ channel KvAP from Aeropyrum pernix suggested interaction between the S6 gating domain and the base of the pore helix, a prediction supported by mutations at this site. These results offer a unique insight into the molecular basis for a physiologically important K+-sensory process in plants
Y1  - 2006
UR  - http://www3.interscience.wiley.com/cgi-bin/issn?DESCRIPTOR=PRINTISSN&VALUE=0960-7412
U6  - https://doi.org/10.1111/j.1365-313X.2006.02690.X
SN  - 0960-7412
ER  -