@unpublished{21994,
  abstract     = {Adaptive plant development is orchestrated, among others, by directional, intercellular transport of the phytohormone auxin. Self-organizing development, such as flexible vasculature formation, depends on so-called auxin canalization, manifested by the gradual formation of auxin transport channels through feedback between auxin signalling and transport. Herein, we identify MAKR6 as an important, novel component in this feedback. MAKR6 expression accumulates strongly in vascular cells and is tightly regulated by auxin via the Aux/IAA-ARF-WRKY23 transcriptional network. MAKR6 is required for auxin canalization-dependent processes, including leaf venation, vasculature regeneration, and de novo auxin channel formation from local auxin sources. Mechanistically, MAKR6 interacts with the PIN1 auxin transporter, modulating its trafficking and polarization. MAKR6 also associates with and integrates two key receptor-like kinase complexes involved in canalization, TMK1/4 and the CAMEL-CANAR. Together, our study establishes MAKR6 as a multifaceted regulator that couples transcriptional auxin signalling to PIN1 repolarization and coordinates multiple RLK-mediated signalling pathways during canalization. This provides mechanistic insights into auxin canalization and exemplifies a framework for exploring similar regulatory nodes in other developmental contexts.},
  author       = {Ge, Zengxiang and Koczka, Lilla and Mazur, Ewa and Molnar, Gergely and Vladimirtsev, Dmitrii and Kassem, Nada and Ait Ikene, Sara and Fiedler, Lukas and Friml, Jiří},
  booktitle    = {bioRxiv},
  title        = {{MAKR6 integrates TMK and CAMEL/CANAR signalling for auxin canalization in Arabidopsis}},
  doi          = {10.1101/2025.10.07.680881},
  year         = {2026},
}

@phdthesis{20964,
  author       = {Vladimirtsev, Dmitrii},
  issn         = {2791-4585},
  pages        = {22},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Armadillo repeat only proteins are master regulators of plant cyclic-nucleotide gated channels}},
  doi          = {10.15479/AT-ISTA-20964},
  year         = {2026},
}

@article{21763,
  abstract     = {Reactive oxygen species (ROS) have been implicated in multiple signaling processes in plants, but the underlying mechanisms and roles remain enigmatic. In this study, we developed a method of live imaging of apoplastic ROS at the root surface. Distinct signals, including auxin, extracellular adenosine triphosphate, and rapid alkalinization factor 1 peptide, induce cytosolic calcium transients and apoplastic ROS bursts. Genetic and optogenetic manipulations of Arabidopsis identified calcium transients as necessary and sufficient for ROS bursts through activation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases RBOHC and RBOHF. Apoplastic ROS bursts are not required, but they do limit gravity-induced root bending. Root bending is sensed by the stretch-activated calcium channel MCA1, leading to NADPH oxidase activation. The resulting ROS production stiffens cell walls to facilitate soil penetration. Apoplastic ROS thus provides a means to balance tissue flexibility and stiffness to navigate soil.},
  author       = {Kulich, Ivan and Vladimirtsev, Dmitrii and Randuch, Marek and Gao, Shiqiang and Citterico, Matteo and Konrad, Kai R. and Nagel, Georg and Wrzaczek, Michael and Cascaro, Léa and Vinet, Pauline and Durand, Pauline and Asnacios, Atef and Verma, Lokesh and Bennett, Malcolm J. and Pandey, Bipin K. and Friml, Jiří},
  issn         = {1095-9203},
  journal      = {Science},
  number       = {6795},
  pages        = {296--300},
  publisher    = {AAAS},
  title        = {{Calcium-triggered apoplastic ROS bursts balance gravity and mechanical signals for soil navigation}},
  doi          = {10.1126/science.adu8197},
  volume       = {392},
  year         = {2026},
}

@article{22301,
  abstract     = {Auxin, primarily indole-3-acetic acid (IAA), is a central regulator of growth and development in land plants, but its physiological role in chlorophyte algae remains unclear. Here, we show that exogenous IAA modulates growth in Chlorella sorokiniana, Chlorella variabilis, and Chlamydomonas reinhardtii in a concentration-dependent manner. Low IAA concentrations promoted growth by accelerating the onset of cell division without affecting cell size, whereas higher concentrations inhibited proliferation. Radiotracer assays showed that all three species take up and release IAA across the plasma membrane through a combination of passive diffusion and energy-dependent, saturable processes. Competition by excess unlabeled natural and synthetic auxins further supported the presence of carrier-mediated transport with broad substrate recognition. Phylogenetic analyses identified potential PIN-like auxin exporters in chlorophytes and other non-plant eukaryotes, and structural modeling supported conservation of the overall PIN fold and predicted auxin-binding residues. However, functional assays in Xenopus laevis oocytes, tobacco BY-2 cultured cells, and Arabidopsis thaliana did not support a role for these proteins in directional auxin export. Instead, non-plant PIN homologs localized predominantly to the endoplasmic reticulum and showed limited or no transport activity in heterologous systems. Together, these findings indicate that auxin responsiveness and basic cellular auxin transport predate canonical PIN-mediated directional auxin export, which appears to be a later innovation of the streptophyte lineage.},
  author       = {Smoljan, Adrijana and Koutnik‐Abele, Sarah and Vladimirtsev, Dmitrii and Klíma, Petr and Bírošíková, Anita and Zhang, Yuzhou and Merrin, Jack and Schuster, Maximilian and Kurtović, Katarina and Hammes, Ulrich Z. and Petrášek, Jan and Friml, Jiří},
  issn         = {1744-7909},
  journal      = {Journal of Integrative Plant Biology},
  publisher    = {Wiley},
  title        = {{Auxin response and PIN‐mediated transport in chlorophyte algae}},
  doi          = {10.1111/jipb.70309},
  year         = {2026},
}

@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},
}

@article{20656,
  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 prerequisite for (1) self-organizing processes, including vascular tissue formation, and (2) directional growth responses such as gravitropism. Here, we identify a mechanism by which auxin signaling directly targets PIN auxin transporters. Via the cell-surface AUXIN-BINDING PROTEIN1 (ABP1)-TRANSMEMBRANE KINASE 1 (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 3 (ABL3) auxin receptor. Such positive feedback between cell-surface auxin signaling and PIN-mediated polar auxin transport is fundamental for robust root gravitropism and presumably 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 Kulich, Ivan and Jaillais, Yvon and Friml, Jiří},
  issn         = {0092-8674},
  journal      = {Cell},
  number       = {22},
  pages        = {6138--6150.e17},
  publisher    = {Elsevier},
  title        = {{ABP1/ABL3-TMK1 cell-surface auxin signaling targets PIN2-mediated auxin fluxes for root gravitropism}},
  doi          = {10.1016/j.cell.2025.08.026},
  volume       = {188},
  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},
  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},
}