@article{12291, abstract = {The phytohormone auxin triggers transcriptional reprogramming through a well-characterized perception machinery in the nucleus. By contrast, mechanisms that underlie fast effects of auxin, such as the regulation of ion fluxes, rapid phosphorylation of proteins or auxin feedback on its transport, remain unclear1,2,3. Whether auxin-binding protein 1 (ABP1) is an auxin receptor has been a source of debate for decades1,4. Here we show that a fraction of Arabidopsis thaliana ABP1 is secreted and binds auxin specifically at an acidic pH that is typical of the apoplast. ABP1 and its plasma-membrane-localized partner, transmembrane kinase 1 (TMK1), are required for the auxin-induced ultrafast global phospho-response and for downstream processes that include the activation of H+-ATPase and accelerated cytoplasmic streaming. abp1 and tmk mutants cannot establish auxin-transporting channels and show defective auxin-induced vasculature formation and regeneration. An ABP1(M2X) variant that lacks the capacity to bind auxin is unable to complement these defects in abp1 mutants. These data indicate that ABP1 is the auxin receptor for TMK1-based cell-surface signalling, which mediates the global phospho-response and auxin canalization.}, author = {Friml, Jiří and Gallei, Michelle C and Gelová, Zuzana and Johnson, Alexander J and Mazur, Ewa and Monzer, Aline and Rodriguez Solovey, Lesia and Roosjen, Mark and Verstraeten, Inge and Živanović, Branka D. and Zou, Minxia and Fiedler, Lukas and Giannini, Caterina and Grones, Peter and Hrtyan, Mónika and Kaufmann, Walter and Kuhn, Andre and Narasimhan, Madhumitha and Randuch, Marek and Rýdza, Nikola and Takahashi, Koji and Tan, Shutang and Teplova, Anastasiia and Kinoshita, Toshinori and Weijers, Dolf and Rakusová, Hana}, issn = {1476-4687}, journal = {Nature}, number = {7927}, pages = {575--581}, publisher = {Springer Nature}, title = {{ABP1–TMK auxin perception for global phosphorylation and auxin canalization}}, doi = {10.1038/s41586-022-05187-x}, volume = {609}, year = {2022}, } @article{10282, abstract = {Advanced transcriptome sequencing has revealed that the majority of eukaryotic genes undergo alternative splicing (AS). Nonetheless, little effort has been dedicated to investigating the functional relevance of particular splicing events, even those in the key developmental and hormonal regulators. Combining approaches of genetics, biochemistry and advanced confocal microscopy, we describe the impact of alternative splicing on the PIN7 gene in the model plant Arabidopsis thaliana. PIN7 encodes a polarly localized transporter for the phytohormone auxin and produces two evolutionarily conserved transcripts, PIN7a and PIN7b. PIN7a and PIN7b, differing in a four amino acid stretch, exhibit almost identical expression patterns and subcellular localization. We reveal that they are closely associated and mutually influence each other's mobility within the plasma membrane. Phenotypic complementation tests indicate that the functional contribution of PIN7b per se is minor, but it markedly reduces the prominent PIN7a activity, which is required for correct seedling apical hook formation and auxin-mediated tropic responses. Our results establish alternative splicing of the PIN family as a conserved, functionally relevant mechanism, revealing an additional regulatory level of auxin-mediated plant development.}, author = {Kashkan, Ivan and Hrtyan, Mónika and Retzer, Katarzyna and Humpolíčková, Jana and Jayasree, Aswathy and Filepová, Roberta and Vondráková, Zuzana and Simon, Sibu and Rombaut, Debbie and Jacobs, Thomas B. and Frilander, Mikko J. and Hejátko, Jan and Friml, Jiří and Petrášek, Jan and Růžička, Kamil}, issn = {1469-8137}, journal = {New Phytologist}, pages = {329--343}, publisher = {Wiley}, title = {{Mutually opposing activity of PIN7 splicing isoforms is required for auxin-mediated tropic responses in Arabidopsis thaliana}}, doi = {10.1111/nph.17792}, volume = {233}, year = {2021}, } @article{9887, abstract = {Clathrin-mediated endocytosis is the major route of entry of cargos into cells and thus underpins many physiological processes. During endocytosis, an area of flat membrane is remodeled by proteins to create a spherical vesicle against intracellular forces. The protein machinery which mediates this membrane bending in plants is unknown. However, it is known that plant endocytosis is actin independent, thus indicating that plants utilize a unique mechanism to mediate membrane bending against high-turgor pressure compared to other model systems. Here, we investigate the TPLATE complex, a plant-specific endocytosis protein complex. It has been thought to function as a classical adaptor functioning underneath the clathrin coat. However, by using biochemical and advanced live microscopy approaches, we found that TPLATE is peripherally associated with clathrin-coated vesicles and localizes at the rim of endocytosis events. As this localization is more fitting to the protein machinery involved in membrane bending during endocytosis, we examined cells in which the TPLATE complex was disrupted and found that the clathrin structures present as flat patches. This suggests a requirement of the TPLATE complex for membrane bending during plant clathrin–mediated endocytosis. Next, we used in vitro biophysical assays to confirm that the TPLATE complex possesses protein domains with intrinsic membrane remodeling activity. These results redefine the role of the TPLATE complex and implicate it as a key component of the evolutionarily distinct plant endocytosis mechanism, which mediates endocytic membrane bending against the high-turgor pressure in plant cells.}, author = {Johnson, Alexander J and Dahhan, Dana A and Gnyliukh, Nataliia and Kaufmann, Walter and Zheden, Vanessa and Costanzo, Tommaso and Mahou, Pierre and Hrtyan, Mónika and Wang, Jie and Aguilera Servin, Juan L and van Damme, Daniël and Beaurepaire, Emmanuel and Loose, Martin and Bednarek, Sebastian Y and Friml, Jiří}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, number = {51}, publisher = {National Academy of Sciences}, title = {{The TPLATE complex mediates membrane bending during plant clathrin-mediated endocytosis}}, doi = {10.1073/pnas.2113046118}, volume = {118}, year = {2021}, } @article{6104, abstract = {Abiotic stress poses constant challenges for plant survival and is a serious problem for global agricultural productivity. On a molecular level, stress conditions result in elevation of reactive oxygen species (ROS) production causing oxidative stress associated with oxidation of proteins and nucleic acids as well as impairment of membrane functions. Adaptation of root growth to ROS accumulation is facilitated through modification of auxin and cytokinin hormone homeostasis. Here, we report that in Arabidopsis root meristem, ROS-induced changes of auxin levels correspond to decreased abundance of PIN auxin efflux carriers at the plasma membrane (PM). Specifically, increase in H2O2 levels affects PIN2 endocytic recycling. We show that the PIN2 intracellular trafficking during adaptation to oxidative stress requires the function of the ADP-ribosylation factor (ARF)-guanine-nucleotide exchange factor (GEF) BEN1, an actin-associated regulator of the trafficking from the PM to early endosomes and, presumably, indirectly, trafficking to the vacuoles. We propose that H2O2 levels affect the actin dynamics thus modulating ARF-GEF-dependent trafficking of PIN2. This mechanism provides a way how root growth acclimates to stress and adapts to a changing environment.}, author = {Zwiewka, Marta and Bielach, Agnieszka and Tamizhselvan, Prashanth and Madhavan, Sharmila and Ryad, Eman Elrefaay and Tan, Shutang and Hrtyan, Mónika and Dobrev, Petre and Vanková, Radomira and Friml, Jiří and Tognetti, Vanesa B.}, issn = {1471-9053}, journal = {Plant and Cell Physiology}, number = {2}, pages = {255--273}, publisher = {Oxford University Press}, title = {{Root adaptation to H2O2-induced oxidative stress by ARF-GEF BEN1- and cytoskeleton-mediated PIN2 trafficking}}, doi = {10.1093/pcp/pcz001}, volume = {60}, year = {2019}, }