@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         = {17529867},
  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{9368,
  abstract     = {The quality control system for messenger RNA (mRNA) is fundamental for cellular activities in eukaryotes. To elucidate the molecular mechanism of 3'-Phosphoinositide-Dependent Protein Kinase1 (PDK1), a master regulator that is essential throughout eukaryotic growth and development, we employed a forward genetic approach to screen for suppressors of the loss-of-function T-DNA insertion double mutant pdk1.1 pdk1.2 in Arabidopsis thaliana. Notably, the severe growth attenuation of pdk1.1 pdk1.2 was rescued by sop21 (suppressor of pdk1.1 pdk1.2), which harbours a loss-of-function mutation in PELOTA1 (PEL1). PEL1 is a homologue of mammalian PELOTA and yeast (Saccharomyces cerevisiae) DOM34p, which each form a heterodimeric complex with the GTPase HBS1 (HSP70 SUBFAMILY B SUPPRESSOR1, also called SUPERKILLER PROTEIN7, SKI7), a protein that is responsible for ribosomal rescue and thereby assures the quality and fidelity of mRNA molecules during translation. Genetic analysis further revealed that a dysfunctional PEL1-HBS1 complex failed to degrade the T-DNA-disrupted PDK1 transcripts, which were truncated but functional, and thus rescued the growth and developmental defects of pdk1.1 pdk1.2. Our studies demonstrated the functionality of a homologous PELOTA-HBS1 complex and identified its essential regulatory role in plants, providing insights into the mechanism of mRNA quality control.},
  author       = {Kong, W and Tan, Shutang and Zhao, Q and Lin, DL and Xu, ZH and Friml, Jiří and Xue, HW},
  issn         = {1532-2548},
  journal      = {Plant Physiology},
  number       = {4},
  pages        = {2003--2020},
  publisher    = {American Society of Plant Biologists},
  title        = {{mRNA surveillance complex PELOTA-HBS1 eegulates phosphoinositide-sependent protein kinase1 and plant growth}},
  doi          = {10.1093/plphys/kiab199},
  volume       = {186},
  year         = {2021},
}

@article{8943,
  abstract     = {The widely used non-steroidal anti-inflammatory drugs (NSAIDs) are derivatives of the phytohormone salicylic acid (SA). SA is well known to regulate plant immunity and development, whereas there have been few reports focusing on the effects of NSAIDs in plants. Our studies here reveal that NSAIDs exhibit largely overlapping physiological activities to SA in the model plant Arabidopsis. NSAID treatments lead to shorter and agravitropic primary roots and inhibited lateral root organogenesis. Notably, in addition to the SA-like action, which in roots involves binding to the protein phosphatase 2A (PP2A), NSAIDs also exhibit PP2A-independent effects. Cell biological and biochemical analyses reveal that many NSAIDs bind directly to and inhibit the chaperone activity of TWISTED DWARF1, thereby regulating actin cytoskeleton dynamics and subsequent endosomal trafficking. Our findings uncover an unexpected bioactivity of human pharmaceuticals in plants and provide insights into the molecular mechanism underlying the cellular action of this class of anti-inflammatory compounds.},
  author       = {Tan, Shutang and Di Donato, Martin and Glanc, Matous and Zhang, Xixi and Klíma, Petr and Liu, Jie and Bailly, Aurélien and Ferro, Noel and Petrášek, Jan and Geisler, Markus and Friml, Jiří},
  issn         = {22111247},
  journal      = {Cell Reports},
  number       = {9},
  publisher    = {Elsevier},
  title        = {{Non-steroidal anti-inflammatory drugs target TWISTED DWARF1-regulated actin dynamics and auxin transport-mediated plant development}},
  doi          = {10.1016/j.celrep.2020.108463},
  volume       = {33},
  year         = {2020},
}

@article{7427,
  abstract     = {Plants, like other multicellular organisms, survive through a delicate balance between growth and defense against pathogens. Salicylic acid (SA) is a major defense signal in plants, and the perception mechanism as well as downstream signaling activating the immune response are known. Here, we identify a parallel SA signaling that mediates growth attenuation. SA directly binds to A subunits of protein phosphatase 2A (PP2A), inhibiting activity of this complex. Among PP2A targets, the PIN2 auxin transporter is hyperphosphorylated in response to SA, leading to changed activity of this important growth regulator. Accordingly, auxin transport and auxin-mediated root development, including growth, gravitropic response, and lateral root organogenesis, are inhibited. This study reveals how SA, besides activating immunity, concomitantly attenuates growth through crosstalk with the auxin distribution network. Further analysis of this dual role of SA and characterization of additional SA-regulated PP2A targets will provide further insights into mechanisms maintaining a balance between growth and defense.},
  author       = {Tan, Shutang and Abas, Melinda F and Verstraeten, Inge and Glanc, Matous and Molnar, Gergely and Hajny, Jakub and Lasák, Pavel and Petřík, Ivan and Russinova, Eugenia and Petrášek, Jan and Novák, Ondřej and Pospíšil, Jiří and Friml, Jiří},
  issn         = {09609822},
  journal      = {Current Biology},
  number       = {3},
  pages        = {381--395.e8},
  publisher    = {Cell Press},
  title        = {{Salicylic acid targets protein phosphatase 2A to attenuate growth in plants}},
  doi          = {10.1016/j.cub.2019.11.058},
  volume       = {30},
  year         = {2020},
}

@article{7600,
  abstract     = {Directional intercellular transport of the phytohormone auxin mediated by PIN FORMED (PIN) efflux carriers plays essential roles in both coordinating patterning processes and integrating multiple external cues by rapidly redirecting auxin fluxes. Multilevel regulations of PIN activity under internal and external cues are complicated; however, the underlying molecular mechanism remains elusive. Here we demonstrate that 3’-Phosphoinositide-Dependent Protein Kinase1 (PDK1), which is conserved in plants and mammals, functions as a molecular hub integrating the upstream lipid signalling and the downstream substrate activity through phosphorylation. Genetic analysis uncovers that loss-of-function Arabidopsis mutant pdk1.1 pdk1.2 exhibits a plethora of abnormalities in organogenesis and growth, due to the defective PIN-dependent auxin transport. Further cellular and biochemical analyses reveal that PDK1 phosphorylates D6 Protein Kinase to facilitate its activity towards PIN proteins. Our studies establish a lipid-dependent phosphorylation cascade connecting membrane composition-based cellular signalling with plant growth and patterning by regulating morphogenetic auxin fluxes.},
  author       = {Tan, Shutang and Zhang, Xixi and Kong, Wei and Yang, Xiao-Li and Molnar, Gergely and Vondráková, Zuzana and Filepová, Roberta and Petrášek, Jan and Friml, Jiří and Xue, Hong-Wei},
  issn         = {20550278},
  journal      = {Nature Plants},
  pages        = {556--569},
  publisher    = {Springer Nature},
  title        = {{The lipid code-dependent phosphoswitch PDK1–D6PK activates PIN-mediated auxin efflux in Arabidopsis}},
  doi          = {10.1038/s41477-020-0648-9},
  volume       = {6},
  year         = {2020},
}