@article{DreyerGajdanowicz2009,
  author    = {Dreyer, Ingo and Gajdanowicz, Pawel},
  title     = {Regulation of the gating mode of the Arabidopsis K+ channel AKT2 is important for adaptation to abiotic stress},
  issn      = {1095-6433},
  doi       = {10.1016/j.cbpa.2009.04.426},
  year      = {2009},
  language  = {en}
}
@article{GarciaMataWangGajdanowiczetal.2010,
  author    = {Garcia-Mata, Carlos and Wang, Jianwen and Gajdanowicz, Pawel and Gonzalez, Wendy and Hills, Adrian and Donald, Naomi and Riedelsberger, Janin and Amtmann, Anna and Dreyer, Ingo and Blatt, Michael R.},
  title     = {A minimal cysteine motif required to activate the SKOR K+ channel of Arabidopsis by the reactive oxygen species H2O2},
  issn      = {0021-9258},
  doi       = {10.1074/jbc.M110.141176},
  year      = {2010},
  abstract  = {Reactive oxygen species (ROS) are essential for development and stress signaling in plants. They contribute to plant defense against pathogens, regulate stomatal transpiration, and influence nutrient uptake and partitioning. Although both Ca2+ and K+ channels of plants are known to be affected, virtually nothing is known of the targets for ROS at a molecular level. Here we report that a single cysteine (Cys) residue within the Kv-like SKOR K+ channel of Arabidopsis thaliana is essential for channel sensitivity to the ROS H2O2. We show that H2O2 rapidly enhanced current amplitude and activation kinetics of heterologously expressed SKOR, and the effects were reversed by the reducing agent dithiothreitol (DTT). Both H2O2 and DTT were active at the outer face of the membrane and current enhancement was strongly dependent on membrane depolarization, consistent with a H2O2-sensitive site on the SKOR protein that is exposed to the outside when the channel is in the open conformation. Cys substitutions identified a single residue, Cys(168) located within the S3 alpha-helix of the voltage sensor complex, to be essential for sensitivity to H2O2. The same Cys residue was a primary determinant for current block by covalent Cys S-methioylation with aqueous methanethiosulfonates. These, and additional data identify Cys168 as a critical target for H2O2, and implicate ROS-mediated control of the K+ channel in regulating mineral nutrient partitioning within the plant.},
  language  = {en}
}
@phdthesis{Gajdanowicz2010,
  author    = {Gajdanowicz, Pawel},
  title     = {Regulation of voltage-gated plant potassium channels},
  address   = {Potsdam},
  pages     = {83 S., [18] Bl. : Ill., graph. Darst.},
  year      = {2010},
  language  = {en}
}
@article{HeldPascaudEckertetal.2011,
  author    = {Held, Katrin and Pascaud, Francois and Eckert, Christian and Gajdanowicz, Pawel and Hashimoto, Kenji and Corratge-Faillie, Claire and Offenborn, Jan Niklas and Lacombe, Benoit and Dreyer, Ingo and Thibaud, Jean-Baptiste and Kudla, J{\"o}rg},
  title     = {Calcium-dependent modulation and plasma membrane targeting of the AKT2 potassium channel by the CBL4/CIPK6 calcium sensor/protein kinase complex},
  series = {Cell research},
  volume    = {21},
  journal   = {Cell research},
  number    = {7},
  publisher = {Nature Publ. Group},
  address   = {Shanghai},
  issn      = {1001-0602},
  doi       = {10.1038/cr.2011.50},
  pages     = {1116 -- 1130},
  year      = {2011},
  abstract  = {Potassium (K(+)) channel function is fundamental to many physiological processes. However, components and mechanisms regulating the activity of plant K(+) channels remain poorly understood. Here, we show that the calcium (Ca(2+)) sensor CBL4 together with the interacting protein kinase CIPK6 modulates the activity and plasma membrane (PM) targeting of the K(+) channel AKT2 from Arabidopsis thaliana by mediating translocation of AKT2 to the PM in plant cells and enhancing AKT2 activity in oocytes. Accordingly, akt2, cbl4 and cipk6 mutants share similar developmental and delayed flowering phenotypes. Moreover, the isolated regulatory C-terminal domain of CIPK6 is sufficient for mediating CBL4- and Ca(2+)-dependent channel translocation from the endoplasmic reticulum membrane to the PM by a novel targeting pathway that is dependent on dual lipid modifications of CBL4 by myristoylation and palmitoylation. Thus, we describe a critical mechanism of ion-channel regulation where a Ca(2+) sensor modulates K(+) channel activity by promoting a kinase interaction-dependent but phosphorylation-independent translocation of the channel to the PM.},
  language  = {en}
}
@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}
}
@article{JohanssonWulfetangePoreeetal.2006,
  author    = {Johansson, Ingela and Wulfetange, Klaas and Poree, Fabien and Michard, Erwan and Gajdanowicz, Pawel and Lacombe, Benoit and Sentenac, Herve and Thibaud, Jean-Baptiste and M{\"u}ller-R{\"o}ber, Bernd and Blatt, Michael R. and Dreyer, Ingo},
  title     = {External K+ modulates the activity of the Arabidopsis potassium channel SKOR via an unusual mechanism},
  issn      = {0960-7412},
  doi       = {10.1111/j.1365-313X.2006.02690.X},
  year      = {2006},
  abstract  = {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},
  language  = {en}
}
@article{GajdanowiczGarciaMataGonzalezetal.2009,
  author    = {Gajdanowicz, Pawel and Garcia-Mata, Carlos and Gonzalez, Wendy and Morales-Navarro, Samuel El{\"i}as and Sharma, Tripti and Gonzalez-Nilo, Fernando Danilo and Gutowicz, Jan and M{\"u}ller-R{\"o}ber, Bernd and Blatt, Michael R. and Dreyer, Ingo},
  title     = {Distinct roles of the last transmembrane domain in controlling Arabidopsis K+ channel activity},
  issn      = {0028-646X},
  doi       = {10.1111/j.1469-8137.2008.02749.x},
  year      = {2009},
  abstract  = {The family of voltage-gated potassium channels in plants presumably evolved from a common ancestor and includes both inward-rectifying (K-in) channels that allow plant cells to accumulate K+ and outward-rectifying (K-out) channels that mediate K+ efflux. Despite their close structural similarities, the activity of Kin channels is largely independent of K+ and depends only on the transmembrane voltage, whereas that of K-out channels responds to the membrane voltage and the prevailing extracellular K+ concentration. Gating of potassium channels is achieved by structural rearrangements within the last transmembrane domain (S6). Here we investigated the functional equivalence of the S6 helices of the Kin channel KAT1 and the K-out channel SKOR by domain-swapping and site-directed mutagenesis. Channel mutants and chimeras were analyzed after expression in Xenopus oocytes. We identified two discrete regions that influence gating differently in both channels, demonstrating a lack of functional complementarity between KAT1 and SKOR. Our findings are supported by molecular models of KAT1 and SKOR in the open and closed states. The role of the S6 segment in gating evolved differently during specialization of the two channel subclasses, posing an obstacle for the transfer of the K+-sensor from K-out to K-in channels.},
  language  = {en}
}