@article{21136, abstract = {The plant hormone auxin regulates growth and development through at least two distinct signaling pathways. The nuclear pathway, involving TIR1/AFB receptors, mediates transcription; whereas the cell surface ABP1-TMK1 auxin perception triggers global ultrafast phosphorylation response. Here, we revisit the rich history of the disputed ABP1 auxin receptor, highlighting recent findings of the involvement of TMKs and other molecular components and focusing on their role in auxin canalization-mediated development.}, author = {Monzer, Aline and Friml, Jiří}, issn = {3005-1401}, journal = {npj Science of Plants}, number = {1}, pages = {2}, publisher = {Springer Nature}, title = {{Historical and mechanistic perspective on ABP1-TMK1-mediated cell surface auxin signaling.}}, doi = {10.1038/s44383-025-00002-8}, volume = {1}, year = {2025}, } @inbook{21255, abstract = {As an important plant hormone to regulate growth and development, auxin has been investigated for more than a century. It had been clearly demonstrated and well-accepted that the intracellular auxin receptors, TIR1/AFBs, are F-box proteins mediating transcriptional auxin signaling by their E3 ubiquitin ligase activity, which targets and sends for degradation the Aux/IAA transcriptional repressors. The recent discovery of adenylate cyclase (AC) and guanylate cyclase (GC) activities for TIR1/AFBs open entirely new perspectives on how auxin signaling can operate. This chapter traces back the history of how canonical transcriptional auxin signaling was established and introduces the discovery of the TIR1/AFBs-mediated nontranscriptional signaling branch. Finally, the current understanding and open questions of how TIR1/AFBs’ AC and GC activities contribute to the transcriptional and nontranscriptional auxin signaling are discussed, highlighting the possibility that cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) act as second messengers in auxin signal transduction.}, author = {Qi, Linlin and Friml, Jiří}, booktitle = {Cryptic Enzymes and Moonlighting Proteins}, editor = {Irving, Helen and Gehring, Chris and Wong, Aloysius}, isbn = {9780443157196}, pages = {299--322}, publisher = {Elsevier}, title = {{Nucleotidyl cyclase activities of TIR1/AFB auxin receptors: new insights into the mechanism of auxin signaling}}, doi = {10.1016/b978-0-443-15719-6.00015-5}, year = {2025}, } @unpublished{20982, abstract = {Plant cells respond to a wide range of stimuli through intracellular calcium (Ca2+) signaling. Cyclic nucleotide-gated channels (CNGCs) are a major class of plant Ca2+ channels, with 20 homologs in Arabidopsis. These tetrameric plasma membrane proteins act downstream of diverse signals, such as phytohormones, extracellular damage, cell wall integrity or temperature. Here, we identify a class of plant-specific proteins, Armadillo Repeat Only (ARO), as essential regulators of possibly all plant CNGCs. Abrogation of functional sporophytic AROs results in a phenotypic pattern strongly reminiscent of CNGC dysfunction, including defects in root gravitropism, root hair growth and morphology, stomatal movement, and responses to extracellular ATP and the phytohormone auxin. aro2/3/4 mutants are fully resistant to the toxic effects caused by overexpression of CNGCs. AROs colocalize and physically interact with multiple CNGCs and modulate CNGC-dependent currents in Xenopus oocytes. Structural modeling and site-directed mutagenesis reveal AROs tetramer formation surrounding the CNGC channel, interacting via its IQ domain. Taken together, plant CNGC channels don’t act alone, but in a larger complex - channelosome, first of a kind in plants.}, author = {Kulich, Ivan and Oulehlová, Denisa and Vladimirtsev, Dmitrii and Zou, Minxia and Lileikyte, Edita and Bondar, Alexey and Kulichová, Katarína and Janda, Martin and Iakovenko, Oksana and Neubergerová, Michaela and Studtrucker, Tanja and Pleskot, Roman and Dietrich, Petra and Fendrych, Matyas and Friml, Jiří}, booktitle = {bioRxiv}, title = {{Armadillo repeat only proteins are required for the function of plant CNGC channels}}, doi = {10.1101/2025.01.06.631460}, year = {2025}, } @phdthesis{19395, abstract = {Plant growth and development rely significantly on phytohormones, with auxin serving as a master regulator, orchestrating processes from embryogenesis to organogenesis, vascular patterning, and environmental adaptation. Since its conceptual proposition by Charles Darwin in 1880 as an endogenous chemical signal influencing phototropism in grass, auxin has captivated scientists seeking to understand how such a small molecule exerts a profound influence on plant development. One particularly fascinating aspect of auxin function is its ability to self-organize its transport. Through a feedback mechanism between auxin perception and directional transport—primarily mediated by PIN auxin transporters—auxin establishes narrow transport channels. This phenomenon, known as auxin canalization, is fundamental to vascular formation, regeneration, and other key developmental processes. Despite advances in our understanding, driven by experimental studies and computational models, auxin canalization remains an enigma, with many unanswered questions. Like other hormones, auxin functions through intricate signaling pathways. It operates through at least two distinct signaling mechanisms: the well-characterized canonical pathway and the less understood non-canonical pathway. While significant progress has been made in elucidating the canonical pathway, the non-canonical mechanisms remain less defined and require further investigation. In this study, we revisit the non-canonical auxin signaling pathway mediated by the cell-surface complex Auxin Binding Protein 1-Transmembrane Kinase 1 (ABP1-TMK1), with a particular focus on its downstream phosphorylation events. We reveal that this auxin-mediated phosphorylation is conserved across the green lineage, underscoring its fundamental role in plant development. We explore key phosphorylation targets, particularly PIN2, which is essential for root gravitropism. To further understand TMK1’s role in diverse developmental processes, we identified and investigated its interactors as potential co-receptors or regulatory components within its signaling network. Given the previously established role of ABP1-TMK1 in auxin canalization, we sought to further investigate this process and identified several TMK1 interactors also involved in this intricate mechanism. These findings provide new insights into the complex regulation of auxin canalization, highlighting a broader and more interconnected signaling framework than previously understood.}, author = {Monzer, Aline}, issn = {2663-337X}, pages = {160}, publisher = {Institute of Science and Technology Austria}, title = {{Cell-Surface Auxin Signaling: Linking molecular pathways to plant development}}, doi = {10.15479/AT-ISTA-19395}, year = {2025}, } @unpublished{19398, abstract = {Receptor-like kinases (RLKs), particularly the Transmembrane Kinase (TMK) family, play essential roles in signaling and development, with TMKs being key components of auxin perception and downstream phosphorylation events. While TMKs’ involvement in auxin canalization, a process essential for vasculature formation and regeneration, has been established, nonetheless, the additional signaling and regulatory partners remain poorly understood. In this study, we identify and characterize seven leucine-rich repeat RLKs (TINT1–TINT7) as novel interactors of TMK1, revealing their diverse evolutionary, structural, and functional characteristics. Our results show that TINTs interact with TMK1 and highlight their roles in regulating various developmental processes. Majority of TINTs contributes, together with TMK1, to auxin canalization, with TINT5 linking TMK1 to other canalization component CAMEL. Beyond canalization, we also establish the role of TINT-TMK1 interactions in processes such as stomatal movement and the hypocotyl’s gravitropic response. These findings suggest that TINTs, through their interaction with TMK1, are integral components of various signaling networks, contributing to both auxin canalization and broader plant development.}, author = {Monzer, Aline and Mazur, Ewa and Rodriguez Solovey, Lesia and Gallei, Michelle C and Zou, Minxia and Smejkal, Michael and Cervenova, Ema and Friml, Jiří}, booktitle = {bioRxiv}, publisher = {Cold Spring Harbor Laboratory}, title = {{TMK interacting network of receptor like kinases for auxin canalization and beyond}}, doi = {10.1101/2025.02.28.640727}, year = {2025}, } @article{20187, abstract = {Very long-chain fatty acids (VLCFAs), being constituents of different types of lipids, are critical factors in plant development, presumably due to their impact on the endomembrane system. The VLCFAs are synthesized in the endoplasmic reticulum by a heterotetrameric enzymatic complex including β-ketoacyl CoA reductase 1 (KCR1), whose mutant is lethal. Here, we describe the ectopic shoot meristems (esm) mutant, a viable kcr1 allele presumably affecting surface properties of the KCR1 protein. This kcr1-2 mutant shows reduced fatty acyl elongation that impacts VLCFAs. The kcr1-2 plants show severe defects during different stages of development, which all correlate with defects in polar localization and subcellular trafficking of PIN auxin transporters and resulting asymmetric auxin distribution. Detailed analysis of KCR1 expression and patterning defects in kcr1-2 suggests that KCR1 plays a role in delineating boundaries around meristematic and specialized differentiating tissues, including root and shoot meristems, initiating lateral roots, lateral root primordia, and trichomes. In these contexts, KCR1-produced VLCFAs may act in a non-cell-autonomous manner. Viable kcr1-2 represents a useful tool to study VLCFA roles in plant development and highlights VLCFAs as critical developmental factors at the interface of cell polarity and tissue development.}, author = {Babic, David and Abualia, Rashed and Fiedler, Lukas and Qi, Linlin and Tellier, Frédérique and Smoljan, Adrijana and Rakusova, Hana and Valošek, Petr and Han, Huibin and Benková, Eva and Faure, Jean Denis and Friml, Jiří}, issn = {1365-313X}, journal = {Plant Journal}, number = {3}, publisher = {Wiley}, title = {{Biosynthesis of very long-chain fatty acids is required for Arabidopsis auxin-mediated embryonic and post-embryonic development}}, doi = {10.1111/tpj.70396}, volume = {123}, year = {2025}, } @article{19421, abstract = {The phytohormone auxin (Aux) is a principal endogenous developmental signal in plants. It mediates transcriptional reprogramming by a well-established canonical signalling mechanism. TIR1/AFB auxin receptors are F-box subunits of an ubiquitin ligase complex; after auxin perception, they associate with Aux/IAA transcriptional repressors and ubiquitinate them for degradation, thus enabling the activation of auxin response factor (ARF) transcription factors1,2,3. Here we revise this paradigm by showing that without TIR1 adenylate cyclase (AC) activity4, auxin-induced degradation of Aux/IAAs is not sufficient to mediate the transcriptional auxin response. Abolishing the TIR1 AC activity does not affect auxin-induced degradation of Aux/IAAs but renders TIR1 non-functional in mediating transcriptional reprogramming and auxin-regulated development, including shoot, root, root hair growth and lateral root formation. Transgenic plants show that local cAMP production in the vicinity of the Aux/IAA–ARF complex by unrelated AC enzymes bypasses the need for auxin perception and is sufficient to induce ARF-mediated transcription. These discoveries revise the canonical model of auxin signalling and establish TIR1/AFB-produced cAMP as a second messenger essential for transcriptional reprograming.}, author = {Chen, Huihuang and Qi, Linlin and Zou, Minxia and Lu, Mengting and Kwiatkowski, M and Pei, Yuanrong and Jaworski, K and Friml, Jiří}, issn = {1476-4687}, journal = {Nature}, pages = {1011--1016}, publisher = {Springer Nature}, title = {{TIR1-produced cAMP as a second messenger in transcriptional auxin signalling}}, doi = {10.1038/s41586-025-08669-w}, volume = {640}, year = {2025}, } @phdthesis{19478, author = {Chen, Huihuang}, issn = {2663-337X}, pages = {118}, publisher = {Institute of Science and Technology Austria}, title = {{The cAMP second messenger in auxin signalling}}, doi = {10.15479/AT-ISTA-19478}, year = {2025}, } @phdthesis{20362, author = {Babic, David}, issn = {2663-337X}, pages = {116}, publisher = {Institute of Science and Technology Austria}, title = {{Mechanisms of auxin-mediated early embryogenesis in Arabidopsis thaliana}}, doi = {10.15479/AT-ISTA-20362}, year = {2025}, } @unpublished{19399, abstract = {Phytohormone auxin and its directional transport mediate much of the remarkably plastic development of higher plants. Positive feedback between auxin signaling and transport is a key prerequisite for (i) self-organizing processes including vascular tissue formation and (ii) directional growth responses such as gravitropism. Here we identify a mechanism, by which auxin signaling directly targets PIN auxin transporters. Via the cell-surface ABP1-TMK1 receptor module, auxin rapidly induces phosphorylation and thus stabilization of PIN2. Following gravistimulation, initial auxin asymmetry activates autophosphorylation of the TMK1 kinase. This induces TMK1 interaction with and phosphorylation of PIN2, stabilizing PIN2 at the lower root side, thus reinforcing asymmetric auxin flow for root bending. Upstream of TMK1 in this regulation, ABP1 acts redundantly with the root-expressed ABP1-LIKE auxin receptor ABL3. Such positive feedback between cell-surface auxin signaling and PIN-mediated polar auxin transport is fundamental for robust root gravitropism and presumably also for other self-organizing developmental phenomena.}, author = {Rodriguez Solovey, Lesia and Fiedler, Lukas and Zou, Minxia and Giannini, Caterina and Monzer, Aline and Vladimirtsev, Dmitrii and Randuch, Marek and Yu, Yongfan and Gelová, Zuzana and Verstraeten, Inge and Hajny, Jakub and Chen, Meng and Tan, Shutang and Hörmayer, Lukas and Li, Lanxin and Marques-Bueno, Maria Mar and Quddoos, Zainab and Molnar, Gergely and Xu, Tongda and Kulich, Ivan and Jaillais, Yvon and Friml, Jiří}, booktitle = {bioRxiv}, publisher = {Cold Spring Harbor Laboratory}, title = {{ABP1/ABL3-TMK1 cell-surface auxin signaling directly targets PIN2-mediated auxin fluxes for root gravitropism}}, doi = {10.1101/2022.11.30.518503}, year = {2025}, } @phdthesis{20364, author = {Giannini, Caterina}, issn = {2663-337X}, keywords = {Auxin Signaling, Plant Development}, pages = {151}, publisher = {Institute of Science and Technology Austria}, title = {{Nuclear and cell surface auxin signaling in A. thaliana developmental transitions}}, doi = {10.15479/AT-ISTA-20364}, year = {2025}, } @article{14251, abstract = {The phytohormone auxin and its directional transport through tissues play a fundamental role in development of higher plants. This polar auxin transport predominantly relies on PIN-FORMED (PIN) auxin exporters. Hence, PIN polarization is crucial for development, but its evolution during the rise of morphological complexity in land plants remains unclear. Here, we performed a cross-species investigation by observing the trafficking and localization of endogenous and exogenous PINs in two bryophytes, Physcomitrium patens and Marchantia polymorpha, and in the flowering plant Arabidopsis thaliana. We confirmed that the GFP fusion did not compromise the auxin export function of all examined PINs by using radioactive auxin export assay and by observing the phenotypic changes in transgenic bryophytes. Endogenous PINs polarize to filamentous apices, while exogenous Arabidopsis PINs distribute symmetrically on the membrane in both bryophytes. In Arabidopsis root epidermis, bryophytic PINs show no defined polarity. Pharmacological interference revealed a strong cytoskeleton dependence of bryophytic but not Arabidopsis PIN polarization. The divergence of PIN polarization and trafficking is also observed within the bryophyte clade and between tissues of individual species. These results collectively reveal a divergence of PIN trafficking and polarity mechanisms throughout land plant evolution and a co-evolution of PIN sequence-based and cell-based polarity mechanisms.}, author = {Tang, Han and Lu, KJ and Zhang, Y and Cheng, YL and Tu, SL and Friml, Jiří}, issn = {2590-3462}, journal = {Plant Communications}, number = {1}, publisher = {Elsevier}, title = {{Divergence of trafficking and polarization mechanisms for PIN auxin transporters during land plant evolution}}, doi = {10.1016/j.xplc.2023.100669}, volume = {5}, year = {2024}, } @article{14447, abstract = {Auxin belongs among major phytohormones and governs multiple aspects of plant growth and development. The establishment of auxin concentration gradients, determines, among other processes, plant organ positioning and growth responses to environmental stimuli. Herein we report the synthesis of new NBD- or DNS-labelled IAA derivatives and the elucidation of their biological activity, fluorescence properties and subcellular accumulation patterns in planta. These novel compounds did not show auxin-like activity, but instead antagonized physiological auxin effects. The DNS-labelled derivatives FL5 and FL6 showed strong anti-auxin activity in roots and hypocotyls, which also occurred at the level of gene transcription as confirmed by quantitative PCR analysis. The auxin antagonism of our derivatives was further demonstrated in vitro using an SPR-based binding assay. The NBD-labelled compound FL4 with the best fluorescence properties proved to be unsuitable to study auxin accumulation patterns in planta. On the other hand, the strongest anti-auxin activity possessing compounds FL5 and FL6 could be useful to study binding mechanisms to auxin receptors and for manipulations of auxin-regulated processes.}, author = {Bieleszová, Kristýna and Hladík, Pavel and Kubala, Martin and Napier, Richard and Brunoni, Federica and Gelová, Zuzana and Fiedler, Lukas and Kulich, Ivan and Strnad, Miroslav and Doležal, Karel and Novák, Ondřej and Friml, Jiří and Žukauskaitė, Asta}, issn = {1573-5087}, journal = {Plant Growth Regulation}, pages = {589--602}, publisher = {Springer Nature}, title = {{New fluorescent auxin derivatives: Anti-auxin activity and accumulation patterns in Arabidopsis thaliana}}, doi = {10.1007/s10725-023-01083-0}, volume = {102}, year = {2024}, } @article{18073, abstract = {Conserved signaling cascades monitor protein-folding homeostasis to ensure proper cellular function. One of the evolutionary conserved key players is IRE1, which maintains endoplasmic reticulum (ER) homeostasis through the unfolded protein response (UPR). Upon accumulation of misfolded proteins in the ER, IRE1 forms clusters on the ER membrane to initiate UPR signaling. What regulates IRE1 cluster formation is not fully understood. Here, we show that the ER lumenal domain (LD) of human IRE1α forms biomolecular condensates in vitro. IRE1α LD condensates were stabilized both by binding to unfolded polypeptides as well as by tethering to model membranes, suggesting their role in assembling IRE1α into signaling-competent stable clusters. Molecular dynamics simulations indicated that weak multivalent interactions drive IRE1α LD clustering. Mutagenesis experiments identified disordered regions in IRE1α LD to control its clustering in vitro and in cells. Importantly, dysregulated clustering of IRE1α mutants led to defects in IRE1α signaling. Our results revealed that disordered regions in IRE1α LD control its clustering and suggest their role as a common strategy in regulating protein assembly on membranes.}, author = {Kettel, Paulina and Marosits, Laura and Spinetti, Elena and Rechberger, Michael and Giannini, Caterina and Radler, Philipp and Niedermoser, Isabell and Fischer, Irmgard and Versteeg, Gijs A. and Loose, Martin and Covino, Roberto and Karagöz, G. Elif}, issn = {1460-2075}, journal = {EMBO Journal}, number = {20}, pages = {4668--4698}, publisher = {Embo Press}, title = {{Disordered regions in the IRE1α ER lumenal domain mediate its stress-induced clustering}}, doi = {10.1038/s44318-024-00207-0}, volume = {43}, year = {2024}, } @article{18311, abstract = {Local wound signaling in plants informs the surrounding tissues about an injury and initiates the regeneration process. In a recent paper published in Cell, Yang and colleagues show the involvement of a single Pep family member from tomato in wound signaling and how exogenous application of this regeneration factor enhances transformation efficiency in crops.}, author = {Hörmayer, Lukas and Friml, Jiří}, issn = {1748-7838}, journal = {Cell Research}, pages = {761--762}, publisher = {Springer Nature}, title = {{Feeling the danger: Local wound signaling in plants}}, doi = {10.1038/s41422-024-01035-x}, volume = {34}, year = {2024}, } @article{18465, abstract = {The phytohormone auxin is polarly transported in plants by PIN-FORMED (PIN) transporters and controls virtually all growth and developmental processes. Canonical PINs possess a long, largely disordered cytosolic loop. Auxin transport by canonical PINs is activated by loop phosphorylation by certain kinases. The structure of the PIN transmembrane domains was recently determined, their transport properties remained poorly characterized, and the role of the loop in the transport process was unclear. Here, we determined the quantitative kinetic parameters of auxin transport mediated by Arabidopsis PINs to mathematically model auxin distribution in roots and to test these predictions in vivo. Using chimeras between transmembrane and loop domains of different PINs, we demonstrate a strong correlation between transport parameters and physiological output, indicating that the loop domain is not only required to activate PIN-mediated auxin transport, but it has an additional role in the transport process by a currently unknown mechanism.}, author = {Janacek, DP and Kolb, M and Schulz, L and Mergner, J and Kuster, B and Glanc, Matous and Friml, Jiří and Ten Tusscher, K and Schwechheimer, C and Hammes, UZ}, issn = {1878-1551}, journal = {Developmental Cell}, number = {14}, pages = {S1534--5807(24)00569--0}, publisher = {Elsevier}, title = {{Transport properties of canonical PIN-FORMED proteins from Arabidopsis and the role of the loop domain in auxin transport}}, doi = {10.1016/j.devcel.2024.09.020}, volume = {59}, year = {2024}, } @article{18582, abstract = {Identification of PIN exporters for auxin, the major coordinative signal in plants, some 25 years ago, signifies a landmark in our understanding of plant-specific mechanisms underlying development and adaptation. Auxin is directionally transported throughout the plant body; a unique feature already envisioned by Darwin and solidified by PINs’ discovery and characterization. The PIN-based auxin distribution network with its complex regulations of PIN expression, localization and activity turned out to underlie a remarkable multitude of developmental processes and represents means to integrate endogenous and environmental signals. Given the recent anniversary, we here summarize past and current developments in this exciting field.}, author = {Luschnig, Christian and Friml, Jiří}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Over 25 years of decrypting PIN-mediated plant development}}, doi = {10.1038/s41467-024-54240-y}, volume = {15}, year = {2024}, } @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{15251, abstract = {Brassinosteroids are steroidal phytohormones that regulate plant development and physiology, including adaptation to environmental stresses. Brassinosteroids are synthesized in the cell interior but bind receptors at the cell surface, necessitating a yet to be identified export mechanism. Here, we show that a member of the ATP-binding cassette (ABC) transporter superfamily, ABCB19, functions as a brassinosteroid exporter. We present its structure in both the substrate-unbound and the brassinosteroid-bound states. Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. In Arabidopsis thaliana, ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses. Our results uncover an elusive export mechanism for bioactive brassinosteroids that is tightly coordinated with brassinosteroid signaling.}, author = {Ying, Wei and Wang, Yaowei and Wei, Hong and Luo, Yongming and Ma, Qian and Zhu, Heyuan and Janssens, Hilde and Vukašinović, Nemanja and Kvasnica, Miroslav and Winne, Johan M. and Gao, Yongxiang and Tan, Shutang and Friml, Jiří and Liu, Xin and Russinova, Eugenia and Sun, Linfeng}, issn = {1095-9203}, journal = {Science}, number = {6689}, pages = {eadj4591}, publisher = {American Association for the Advancement of Science}, title = {{Structure and function of the Arabidopsis ABC transporter ABCB19 in brassinosteroid export}}, doi = {10.1126/science.adj4591}, volume = {383}, year = {2024}, } @article{15257, abstract = {Root gravitropic bending represents a fundamental aspect of terrestrial plant physiology. Gravity is perceived by sedimentation of starch-rich plastids (statoliths) to the bottom of the central root cap cells. Following gravity perception, intercellular auxin transport is redirected downwards leading to an asymmetric auxin accumulation at the lower root side causing inhibition of cell expansion, ultimately resulting in downwards bending. How gravity-induced statoliths repositioning is translated into asymmetric auxin distribution remains unclear despite PIN auxin efflux carriers and the Negative Gravitropic Response of roots (NGR) proteins polarize along statolith sedimentation, thus providing a plausible mechanism for auxin flow redirection. In this study, using a functional NGR1-GFP construct, we visualized the NGR1 localization on the statolith surface and plasma membrane (PM) domains in close proximity to the statoliths, correlating with their movements. We determined that NGR1 binding to these PM domains is indispensable for NGR1 functionality and relies on cysteine acylation and adjacent polybasic regions as well as on lipid and sterol PM composition. Detailed timing of the early events following graviperception suggested that both NGR1 repolarization and initial auxin asymmetry precede the visible PIN3 polarization. This discrepancy motivated us to unveil a rapid, NGR-dependent translocation of PIN-activating AGCVIII kinase D6PK towards lower PMs of gravity-perceiving cells, thus providing an attractive model for rapid redirection of auxin fluxes following gravistimulation.}, author = {Kulich, Ivan and Schmid, Julia and Teplova, Anastasiia and Qi, Linlin and Friml, Jiří}, issn = {2050-084X}, journal = {eLife}, keywords = {General Immunology and Microbiology, General Biochemistry, Genetics and Molecular Biology, General Medicine, General Neuroscience}, publisher = {eLife Sciences Publications}, title = {{Rapid translocation of NGR proteins driving polarization of PIN-activating D6 protein kinase during root gravitropism}}, doi = {10.7554/elife.91523}, volume = {12}, year = {2024}, }