@article{GajdanowiczMichardSandmannetal.2011, author = {Gajdanowicz, Pawel and Michard, Erwan and Sandmann, Michael and Rocha, Marcio and Correa, Luiz Gustavo Guedes and Ramirez-Aguilar, Santiago J. and Gomez-Porras, Judith L. and Gonzalez, Wendy and Thibaud, Jean-Baptiste and van Dongen, Joost T. and Dreyer, Ingo}, title = {Potassium (K plus ) gradients serve as a mobile energy source in plant vascular tissues}, series = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {108}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, number = {2}, publisher = {National Acad. of Sciences}, address = {Washington}, issn = {0027-8424}, doi = {10.1073/pnas.1009777108}, pages = {864 -- 869}, year = {2011}, abstract = {The essential mineral nutrient potassium (K(+)) is the most important inorganic cation for plants and is recognized as a limiting factor for crop yield and quality. Nonetheless, it is only partially understood how K(+) contributes to plant productivity. K(+) is used as a major active solute to maintain turgor and to drive irreversible and reversible changes in cell volume. K(+) also plays an important role in numerous metabolic processes, for example, by serving as an essential cofactor of enzymes. Here, we provide evidence for an additional, previously unrecognized role of K(+) in plant growth. By combining diverse experimental approaches with computational cell simulation, we show that K(+) circulating in the phloem serves as a decentralized energy storage that can be used to overcome local energy limitations. Posttranslational modification of the phloem-expressed Arabidopsis K(+) channel AKT2 taps this "potassium battery," which then efficiently assists the plasma membrane H(+)-ATPase in energizing the transmembrane phloem (re) loading processes.}, language = {en} } @misc{RiedelsbergerDreyerGonzalez2015, author = {Riedelsberger, Janin and Dreyer, Ingo and Gonzalez, Wendy}, title = {Outward rectification of voltage-gated K+ channels evolved at least twice in life history}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {521}, issn = {1866-8372}, doi = {10.25932/publishup-40959}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-409594}, pages = {17}, year = {2015}, abstract = {Voltage-gated potassium (K+) channels are present in all living systems. Despite high structural similarities in the transmembrane domains (TMD), this K+ channel type segregates into at least two main functional categories-hyperpolarization-activated, inward-rectifying (Kin) and depolarization-activated, outward-rectifying (Kout) channels. Voltage-gated K+ channels sense the membrane voltage via a voltage-sensing domain that is connected to the conduction pathway of the channel. It has been shown that the voltage-sensing mechanism is the same in Kin and Kout channels, but its performance results in opposite pore conformations. It is not known how the different coupling of voltage-sensor and pore is implemented. Here, we studied sequence and structural data of voltage-gated K+ channels from animals and plants with emphasis on the property of opposite rectification. We identified structural hotspots that alone allow already the distinction between Kin and Kout channels. Among them is a loop between TMD S5 and the pore that is very short in animal Kout, longer in plant and animal Kin and the longest in plant Kout channels. In combination with further structural and phylogenetic analyses this finding suggests that outward-rectification evolved twice and independently in the animal and plant kingdom.}, language = {en} }