TY - JOUR AB - 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. AU - Johnson, Alexander J AU - Dahhan, Dana A AU - Gnyliukh, Nataliia AU - Kaufmann, Walter AU - Zheden, Vanessa AU - Costanzo, Tommaso AU - Mahou, Pierre AU - Hrtyan, Mónika AU - Wang, Jie AU - Aguilera Servin, Juan L AU - van Damme, Daniël AU - Beaurepaire, Emmanuel AU - Loose, Martin AU - Bednarek, Sebastian Y AU - Friml, Jiří ID - 9887 IS - 51 JF - Proceedings of the National Academy of Sciences TI - The TPLATE complex mediates membrane bending during plant clathrin-mediated endocytosis VL - 118 ER - TY - GEN AB - Raw data generated from the publication - The TPLATE complex mediates membrane bending during plant clathrin-mediated endocytosis by Johnson et al., 2021 In PNAS AU - Johnson, Alexander J ID - 14988 TI - Raw data from Johnson et al, PNAS, 2021 ER - TY - THES AB - Blood – this is what animals use to heal wounds fast and efficient. Plants do not have blood circulation and their cells cannot move. However, plants have evolved remarkable capacities to regenerate tissues and organs preventing further damage. In my PhD research, I studied the wound healing in the Arabidopsis root. I used a UV laser to ablate single cells in the root tip and observed the consequent wound healing. Interestingly, the inner adjacent cells induced a division plane switch and subsequently adopted the cell type of the killed cell to replace it. We termed this form of wound healing “restorative divisions”. This initial observation triggered the questions of my PhD studies: How and why do cells orient their division planes, how do they feel the wound and why does this happen only in inner adjacent cells. For answering these questions, I used a quite simple experimental setup: 5 day - old seedlings were stained with propidium iodide to visualize cell walls and dead cells; ablation was carried out using a special laser cutter and a confocal microscope. Adaptation of the novel vertical microscope system made it possible to observe wounds in real time. This revealed that restorative divisions occur at increased frequency compared to normal divisions. Additionally, the major plant hormone auxin accumulates in wound adjacent cells and drives the expression of the wound-stress responsive transcription factor ERF115. Using this as a marker gene for wound responses, we found that an important part of wound signalling is the sensing of the collapse of the ablated cell. The collapse causes a radical pressure drop, which results in strong tissue deformations. These deformations manifest in an invasion of the now free spot specifically by the inner adjacent cells within seconds, probably because of higher pressure of the inner tissues. Long-term imaging revealed that those deformed cells continuously expand towards the wound hole and that this is crucial for the restorative division. These wound-expanding cells exhibit an abnormal, biphasic polarity of microtubule arrays before the division. Experiments inhibiting cell expansion suggest that it is the biphasic stretching that induces those MT arrays. Adapting the micromanipulator aspiration system from animal scientists at our institute confirmed the hypothesis that stretching influences microtubule stability. In conclusion, this shows that microtubules react to tissue deformation and this facilitates the observed division plane switch. This puts mechanical cues and tensions at the most prominent position for explaining the growth and wound healing properties of plants. Hence, it shines light onto the importance of understanding mechanical signal transduction. AU - Hörmayer, Lukas ID - 9992 SN - 2663-337X TI - Wound healing in the Arabidopsis root meristem ER - TY - JOUR AB - Availability of the essential macronutrient nitrogen in soil plays a critical role in plant growth, development, and impacts agricultural productivity. Plants have evolved different strategies for sensing and responding to heterogeneous nitrogen distribution. Modulation of root system architecture, including primary root growth and branching, is among the most essential plant adaptions to ensure adequate nitrogen acquisition. However, the immediate molecular pathways coordinating the adjustment of root growth in response to distinct nitrogen sources, such as nitrate or ammonium, are poorly understood. Here, we show that growth as manifested by cell division and elongation is synchronized by coordinated auxin flux between two adjacent outer tissue layers of the root. This coordination is achieved by nitrate‐dependent dephosphorylation of the PIN2 auxin efflux carrier at a previously uncharacterized phosphorylation site, leading to subsequent PIN2 lateralization and thereby regulating auxin flow between adjacent tissues. A dynamic computer model based on our experimental data successfully recapitulates experimental observations. Our study provides mechanistic insights broadening our understanding of root growth mechanisms in dynamic environments. AU - Ötvös, Krisztina AU - Marconi, Marco AU - Vega, Andrea AU - O’Brien, Jose AU - Johnson, Alexander J AU - Abualia, Rashed AU - Antonielli, Livio AU - Montesinos López, Juan C AU - Zhang, Yuzhou AU - Tan, Shutang AU - Cuesta, Candela AU - Artner, Christina AU - Bouguyon, Eleonore AU - Gojon, Alain AU - Friml, Jiří AU - Gutiérrez, Rodrigo A. AU - Wabnik, Krzysztof T AU - Benková, Eva ID - 9010 IS - 3 JF - EMBO Journal SN - 02614189 TI - Modulation of plant root growth by nitrogen source-defined regulation of polar auxin transport VL - 40 ER - TY - JOUR AB - Auxin is a major plant growth regulator, but current models on auxin perception and signaling cannot explain the whole plethora of auxin effects, in particular those associated with rapid responses. A possible candidate for a component of additional auxin perception mechanisms is the AUXIN BINDING PROTEIN 1 (ABP1), whose function in planta remains unclear. Here we combined expression analysis with gain- and loss-of-function approaches to analyze the role of ABP1 in plant development. ABP1 shows a broad expression largely overlapping with, but not regulated by, transcriptional auxin response activity. Furthermore, ABP1 activity is not essential for the transcriptional auxin signaling. Genetic in planta analysis revealed that abp1 loss-of-function mutants show largely normal development with minor defects in bolting. On the other hand, ABP1 gain-of-function alleles show a broad range of growth and developmental defects, including root and hypocotyl growth and bending, lateral root and leaf development, bolting, as well as response to heat stress. At the cellular level, ABP1 gain-of-function leads to impaired auxin effect on PIN polar distribution and affects BFA-sensitive PIN intracellular aggregation. The gain-of-function analysis suggests a broad, but still mechanistically unclear involvement of ABP1 in plant development, possibly masked in abp1 loss-of-function mutants by a functional redundancy. AU - Gelová, Zuzana AU - Gallei, Michelle C AU - Pernisová, Markéta AU - Brunoud, Géraldine AU - Zhang, Xixi AU - Glanc, Matous AU - Li, Lanxin AU - Michalko, Jaroslav AU - Pavlovicova, Zlata AU - Verstraeten, Inge AU - Han, Huibin AU - Hajny, Jakub AU - Hauschild, Robert AU - Čovanová, Milada AU - Zwiewka, Marta AU - Hörmayer, Lukas AU - Fendrych, Matyas AU - Xu, Tongda AU - Vernoux, Teva AU - Friml, Jiří ID - 8931 JF - Plant Science KW - Agronomy and Crop Science KW - Plant Science KW - Genetics KW - General Medicine SN - 0168-9452 TI - Developmental roles of auxin binding protein 1 in Arabidopsis thaliana VL - 303 ER -