@article{18596, abstract = {Hormone perception and signaling pathways have a fundamental regulatory function in the physiological processes of plants. Cytokinins, a class of plant hormones, regulate cell division and meristem maintenance. The cytokinin signaling pathway is well established in the model plant Arabidopsis thaliana. Several negative feedback mechanisms, tightly controlling cytokinin signaling output, have been described previously. In this study, we identified a new feedback mechanism executed through alternative splicing of the cytokinin receptor AHK4/CRE1. A novel splicing variant named CRE1int7 results from seventh intron retention, introducing a premature termination codon in the transcript. We showed that CRE1int7 is translated in planta into a truncated receptor lacking the C-terminal receiver domain essential for signal transduction. CRE1int7 can bind cytokinin but cannot activate the downstream cascade. We present a novel negative feedback mechanism of the cytokinin signaling pathway, facilitated by a decoy receptor that can inactivate canonical cytokinin receptors via dimerization and compete with them for ligand binding. Ensuring proper plant growth and development requires precise control of the cytokinin signaling pathway at several levels. CRE1int7 represents a so-far unknown mechanism for fine-tuning the cytokinin signaling pathway in Arabidopsis.}, author = {Králová, Michaela and Kubalová, Ivona and Hajný, Jakub and Kubiasova, Karolina and Vagaská, Karolína and Ge, Zengxiang and Gallei, Michelle C and Semerádová, Hana and Kuchařová, Anna and Hönig, Martin and Monzer, Aline and Kovačik, Martin and Friml, Jiří and Novák, Ondřej and Benková, Eva and Ikeda, Yoshihisa and Zalabák, David}, issn = {1674-2052}, journal = {Molecular Plant}, number = {12}, pages = {1850--1865}, publisher = {Elsevier}, title = {{A decoy receptor derived from alternative splicing fine-tunes cytokinin signaling in Arabidopsis}}, doi = {10.1016/j.molp.2024.11.001}, volume = {17}, year = {2024}, } @article{12239, abstract = {Biological systems are the sum of their dynamic three-dimensional (3D) parts. Therefore, it is critical to study biological structures in 3D and at high resolution to gain insights into their physiological functions. Electron microscopy of metal replicas of unroofed cells and isolated organelles has been a key technique to visualize intracellular structures at nanometer resolution. However, many of these methods require specialized equipment and personnel to complete them. Here, we present novel accessible methods to analyze biological structures in unroofed cells and biochemically isolated organelles in 3D and at nanometer resolution, focusing on Arabidopsis clathrin-coated vesicles (CCVs). While CCVs are essential trafficking organelles, their detailed structural information is lacking due to their poor preservation when observed via classical electron microscopy protocols experiments. First, we establish a method to visualize CCVs in unroofed cells using scanning transmission electron microscopy tomography, providing sufficient resolution to define the clathrin coat arrangements. Critically, the samples are prepared directly on electron microscopy grids, removing the requirement to use extremely corrosive acids, thereby enabling the use of this method in any electron microscopy lab. Secondly, we demonstrate that this standardized sample preparation allows the direct comparison of isolated CCV samples with those visualized in cells. Finally, to facilitate the high-throughput and robust screening of metal replicated samples, we provide a deep learning analysis method to screen the “pseudo 3D” morphologies of CCVs imaged with 2D modalities. Collectively, our work establishes accessible ways to examine the 3D structure of biological samples and provide novel insights into the structure of plant CCVs.}, author = {Johnson, Alexander J and Kaufmann, Walter and Sommer, Christoph M and Costanzo, Tommaso and Dahhan, Dana A. and Bednarek, Sebastian Y. and Friml, Jiří}, issn = {1674-2052}, journal = {Molecular Plant}, keywords = {Plant Science, Molecular Biology}, number = {10}, pages = {1533--1542}, publisher = {Elsevier}, title = {{Three-dimensional visualization of planta clathrin-coated vesicles at ultrastructural resolution}}, doi = {10.1016/j.molp.2022.09.003}, volume = {15}, year = {2022}, } @article{8992, abstract = {The phytohormone auxin plays a central role in shaping plant growth and development. With decades of genetic and biochemical studies, numerous core molecular components and their networks, underlying auxin biosynthesis, transport, and signaling, have been identified. Notably, protein phosphorylation, catalyzed by kinases and oppositely hydrolyzed by phosphatases, has been emerging to be a crucial type of post-translational modification, regulating physiological and developmental auxin output at all levels. In this review, we comprehensively discuss earlier and recent advances in our understanding of genetics, biochemistry, and cell biology of the kinases and phosphatases participating in auxin action. We provide insights into the mechanisms by which reversible protein phosphorylation defines developmental auxin responses, discuss current challenges, and provide our perspectives on future directions involving the integration of the control of protein phosphorylation into the molecular auxin network.}, author = {Tan, Shutang and Luschnig, Christian and Friml, Jiří}, issn = {1752-9867}, journal = {Molecular Plant}, number = {1}, pages = {151--165}, publisher = {Elsevier}, title = {{Pho-view of auxin: Reversible protein phosphorylation in auxin biosynthesis, transport and signaling}}, doi = {10.1016/j.molp.2020.11.004}, volume = {14}, year = {2021}, } @article{15037, abstract = {Protein abundance and localization at the plasma membrane (PM) shapes plant development and mediates adaptation to changing environmental conditions. It is regulated by ubiquitination, a post-translational modification crucial for the proper sorting of endocytosed PM proteins to the vacuole for subsequent degradation. To understand the significance and the variety of roles played by this reversible modification, the function of ubiquitin receptors, which translate the ubiquitin signature into a cellular response, needs to be elucidated. In this study, we show that TOL (TOM1-like) proteins function in plants as multivalent ubiquitin receptors, governing ubiquitinated cargo delivery to the vacuole via the conserved Endosomal Sorting Complex Required for Transport (ESCRT) pathway. TOL2 and TOL6 interact with components of the ESCRT machinery and bind to K63-linked ubiquitin via two tandemly arranged conserved ubiquitin-binding domains. Mutation of these domains results not only in a loss of ubiquitin binding but also altered localization, abolishing TOL6 ubiquitin receptor activity. Function and localization of TOL6 is itself regulated by ubiquitination, whereby TOL6 ubiquitination potentially modulates degradation of PM-localized cargoes, assisting in the fine-tuning of the delicate interplay between protein recycling and downregulation. Taken together, our findings demonstrate the function and regulation of a ubiquitin receptor that mediates vacuolar degradation of PM proteins in higher plants.}, author = {Moulinier-Anzola, Jeanette and Schwihla, Maximilian and De-Araújo, Lucinda and Artner, Christina and Jörg, Lisa and Konstantinova, Nataliia and Luschnig, Christian and Korbei, Barbara}, issn = {1674-2052}, journal = {Molecular Plant}, keywords = {Plant Science, Molecular Biology}, number = {5}, pages = {717--731}, publisher = {Elsevier}, title = {{TOLs function as ubiquitin receptors in the early steps of the ESCRT pathway in higher plants}}, doi = {10.1016/j.molp.2020.02.012}, volume = {13}, year = {2020}, } @article{8271, author = {He, Peng and Zhang, Yuzhou and Xiao, Guanghui}, issn = {1752-9867}, journal = {Molecular Plant}, number = {9}, pages = {1238--1240}, publisher = {Elsevier}, title = {{Origin of a subgenome and genome evolution of allotetraploid cotton species}}, doi = {10.1016/j.molp.2020.07.006}, volume = {13}, year = {2020}, }