TY - JOUR A1 - Liu, Qinsong A1 - Vain, Thomas A1 - Viotti, Corrado A1 - Doyle, Siamsa M. A1 - Tarkowska, Danuse A1 - Novak, Ondrej A1 - Zipfel, Cyril A1 - Sitbon, Folke A1 - Robert, Stephanie A1 - Hofius, Daniel T1 - Vacuole integrity maintained by DUF300 proteins is required for brassinosteroid signaling regulation JF - Molecular plant N2 - Brassinosteroid (BR) hormone signaling controls multiple processes during plant growth and development and is initiated at the plasma membrane through the receptor kinase BRASSINOSTEROID INSENSITIVE1 (BRI1) together with co-receptors such as BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1). BRI1 abundance is regulated by endosomal recycling and vacuolar targeting, but the role of vacuole-related proteins in BR receptor dynamics and BR responses remains elusive. Here, we show that the absence of two DUF300 domain-containing tonoplast proteins, LAZARUS1 (LAZ1) and LAZ1 HOMOLOG1 (LAZ1H1), causes vacuole morphology defects, growth inhibition, and constitutive activation of BR signaling. Intriguingly, tonoplast accumulation of BAK1 was substantially increased and appeared causally linked to enhanced BRI1 trafficking and degradation in laz1 laz1h1 plants. Since unrelated vacuole mutants exhibited normal BR responses, our findings indicate that DUF300 proteins play distinct roles in the regulation of BR signaling by maintaining vacuole integrity required to balance subcellular BAK1 pools and BR receptor distribution. KW - brassinosteroid signaling KW - vacuole integrity KW - DUF300 proteins KW - tonoplast KW - Arabidopsis Y1 - 2018 U6 - https://doi.org/10.1016/j.molp.2017.12.015 SN - 1674-2052 SN - 1752-9867 VL - 11 IS - 4 SP - 553 EP - 567 PB - Cell Press CY - Cambridge ER - TY - JOUR A1 - Poxson, David J. A1 - Karady, Michal A1 - Gabrielsson, Roger A1 - Alkattan, Aziz Y. A1 - Gustavsson, Anna A1 - Doyle, Siamsa M. A1 - Robert, Stephanie A1 - Ljung, Karin A1 - Grebe, Markus A1 - Simon, Daniel T. A1 - Berggren, Magnus T1 - Regulating plant physiology with organic electronics JF - Proceedings of the National Academy of Sciences of the United States of America N2 - The organic electronic ion pump (OEIP) provides flow-free and accurate delivery of small signaling compounds at high spatio-temporal resolution. To date, the application of OEIPs has been limited to delivery of nonaromatic molecules to mammalian systems, particularly for neuroscience applications. However, many long-standing questions in plant biology remain unanswered due to a lack of technology that precisely delivers plant hormones, based on cyclic alkanes or aromatic structures, to regulate plant physiology. Here, we report the employment of OEIPs for the delivery of the plant hormone auxin to induce differential concentration gradients and modulate plant physiology. We fabricated OEIP devices based on a synthesized dendritic polyelectrolyte that enables electrophoretic transport of aromatic substances. Delivery of auxin to transgenic Arabidopsis thaliana seedlings in vivo was monitored in real time via dynamic fluorescent auxin-response reporters and induced physiological responses in roots. Our results provide a starting point for technologies enabling direct, rapid, and dynamic electronic interaction with the biochemical regulation systems of plants. KW - auxin KW - Arabidopsis thaliana KW - dendritic polymer KW - bioelectronics KW - polyelectrolyte Y1 - 2017 U6 - https://doi.org/10.1073/pnas.1617758114 SN - 0027-8424 VL - 114 SP - 4597 EP - 4602 PB - National Acad. of Sciences CY - Washington ER - TY - JOUR A1 - Dejonghe, Wim A1 - Kuenen, Sabine A1 - Mylle, Evelien A1 - Vasileva, Mina A1 - Keech, Olivier A1 - Viotti, Corrado A1 - Swerts, Jef A1 - Fendrych, Matyas A1 - Ortiz-Morea, Fausto Andres A1 - Mishev, Kiril A1 - Delang, Simon A1 - Scholl, Stefan A1 - Zarza, Xavier A1 - Heilmann, Mareike A1 - Kourelis, Jiorgos A1 - Kasprowicz, Jaroslaw A1 - Nguyen, Le Son Long A1 - Drozdzecki, Andrzej A1 - Van Houtte, Isabelle A1 - Szatmari, Anna-Maria A1 - Majda, Mateusz A1 - Baisa, Gary A1 - Bednarek, Sebastian York A1 - Robert, Stephanie A1 - Audenaert, Dominique A1 - Testerink, Christa A1 - Munnik, Teun A1 - Van Damme, Daniel A1 - Heilmann, Ingo A1 - Schumacher, Karin A1 - Winne, Johan A1 - Friml, Jiri A1 - Verstreken, Patrik A1 - Russinova, Eugenia T1 - Mitochondrial uncouplers inhibit clathrin-mediated endocytosis largely through cytoplasmic acidification JF - Nature Communications N2 - ATP production requires the establishment of an electrochemical proton gradient across the inner mitochondrial membrane. Mitochondrial uncouplers dissipate this proton gradient and disrupt numerous cellular processes, including vesicular trafficking, mainly through energy depletion. Here we show that Endosidin9 (ES9), a novel mitochondrial uncoupler, is a potent inhibitor of clathrin-mediated endocytosis (CME) in different systems and that ES9 induces inhibition of CME not because of its effect on cellular ATP, but rather due to its protonophore activity that leads to cytoplasm acidification. We show that the known tyrosine kinase inhibitor tyrphostinA23, which is routinely used to block CME, displays similar properties, thus questioning its use as a specific inhibitor of cargo recognition by the AP-2 adaptor complex via tyrosine motif-based endocytosis signals. Furthermore, we show that cytoplasm acidification dramatically affects the dynamics and recruitment of clathrin and associated adaptors, and leads to reduction of phosphatidylinositol 4,5-biphosphate from the plasma membrane. Y1 - 2016 U6 - https://doi.org/10.1038/ncomms11710 SN - 2041-1723 VL - 7 SP - 1959 EP - 1968 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Majda, Mateusz A1 - Grones, Peter A1 - Sintorn, Ida-Maria A1 - Vain, Thomas A1 - Milani, Pascale A1 - Krupinski, Pawel A1 - Zagorska-Marek, Beata A1 - Viotti, Corrado A1 - Jonsson, Henrik A1 - Mellerowicz, Ewa J. A1 - Hamant, Olivier A1 - Robert, Stephanie T1 - Mechanochemical Polarization of Contiguous Cell Walls Shapes Plant Pavement Cells JF - Developmental cell N2 - The epidermis of aerial plant organs is thought to be limiting for growth, because it acts as a continuous load-bearing layer, resisting tension. Leaf epidermis contains jigsaw puzzle piece-shaped pavement cells whose shape has been proposed to be a result of subcellular variations in expansion rate that induce local buckling events. Paradoxically, such local compressive buckling should not occur given the tensile stresses across the epidermis. Using computational modeling, we show that the simplest scenario to explain pavement cell shapes within an epidermis under tension must involve mechanical wall heterogeneities across and along the anticlinal pavement cell walls between adjacent cells. Combining genetics, atomic force microscopy, and immunolabeling, we demonstrate that contiguous cell walls indeed exhibit hybrid mechanochemical properties. Such biochemical wall heterogeneities precede wall bending. Altogether, this provides a possible mechanism for the generation of complex plant cell shapes. Y1 - 2017 U6 - https://doi.org/10.1016/j.devcel.2017.10.017 SN - 1534-5807 SN - 1878-1551 VL - 43 SP - 290 EP - + PB - Cell Press CY - Cambridge ER -