@article{14339,
  abstract     = {Lateral roots are typically maintained at non-vertical angles with respect to gravity. These gravitropic setpoint angles are intriguing because their maintenance requires that roots are able to effect growth response both with and against the gravity vector, a phenomenon previously attributed to gravitropism acting against an antigravitropic offset mechanism. Here we show how the components mediating gravitropism in the vertical primary root—PINs and phosphatases acting upon them—are reconfigured in their regulation such that lateral root growth at a range of angles can be maintained. We show that the ability of Arabidopsis lateral roots to bend both downward and upward requires the generation of auxin asymmetries and is driven by angle-dependent variation in downward gravitropic auxin flux acting against angle-independent upward, antigravitropic flux. Further, we demonstrate a symmetry in auxin distribution in lateral roots at gravitropic setpoint angle that can be traced back to a net, balanced polarization of PIN3 and PIN7 auxin transporters in the columella. These auxin fluxes are shifted by altering PIN protein phosphoregulation in the columella, either by introducing PIN3 phosphovariant versions or via manipulation of levels of the phosphatase subunit PP2A/RCN1. Finally, we show that auxin, in addition to driving lateral root directional growth, acts within the lateral root columella to induce more vertical growth by increasing RCN1 levels, causing a downward shift in PIN3 localization, thereby diminishing the magnitude of the upward, antigravitropic auxin flux.},
  author       = {Roychoudhry, S and Sageman-Furnas, K and Wolverton, C and Grones, Peter and Tan, Shutang and Molnar, Gergely and De Angelis, M and Goodman, HL and Capstaff, N and JPB, Lloyd and Mullen, J and Hangarter, R and Friml, Jiří and Kepinski, S},
  issn         = {2055-0278},
  journal      = {Nature Plants},
  pages        = {1500--1513},
  publisher    = {Springer Nature},
  title        = {{Antigravitropic PIN polarization maintains non-vertical growth in lateral roots}},
  doi          = {10.1038/s41477-023-01478-x},
  volume       = {9},
  year         = {2023},
}

@article{7106,
  abstract     = {PIN-FORMED (PIN) transporters mediate directional, intercellular movement of the phytohormone auxin in land plants. To elucidate the evolutionary origins of this developmentally crucial mechanism, we analysed the single PIN homologue of a simple green alga Klebsormidium flaccidum. KfPIN functions as a plasma membrane-localized auxin exporter in land plants and heterologous models. While its role in algae remains unclear, PIN-driven auxin export is probably an ancient and conserved trait within streptophytes.},
  author       = {Skokan, Roman and Medvecká, Eva and Viaene, Tom and Vosolsobě, Stanislav and Zwiewka, Marta and Müller, Karel and Skůpa, Petr and Karady, Michal and Zhang, Yuzhou and Janacek, Dorina P. and Hammes, Ulrich Z. and Ljung, Karin and Nodzyński, Tomasz and Petrášek, Jan and Friml, Jiří},
  issn         = {2055-0278},
  journal      = {Nature Plants},
  number       = {11},
  pages        = {1114--1119},
  publisher    = {Springer Nature},
  title        = {{PIN-driven auxin transport emerged early in streptophyte evolution}},
  doi          = {10.1038/s41477-019-0542-5},
  volume       = {5},
  year         = {2019},
}

@article{5673,
  abstract     = {Cell polarity, manifested by the localization of proteins to distinct polar plasma membrane domains, is a key prerequisite of multicellular life. In plants, PIN auxin transporters are prominent polarity markers crucial for a plethora of developmental processes. Cell polarity mechanisms in plants are distinct from other eukaryotes and still largely elusive. In particular, how the cell polarities are propagated and maintained following cell division remains unknown. Plant cytokinesis is orchestrated by the cell plate—a transient centrifugally growing endomembrane compartment ultimately forming the cross wall1. Trafficking of polar membrane proteins is typically redirected to the cell plate, and these will consequently have opposite polarity in at least one of the daughter cells2–5. Here, we provide mechanistic insights into post-cytokinetic re-establishment of cell polarity as manifested by the apical, polar localization of PIN2. We show that the apical domain is defined in a cell-intrinsic manner and that re-establishment of PIN2 localization to this domain requires de novo protein secretion and endocytosis, but not basal-to-apical transcytosis. Furthermore, we identify a PINOID-related kinase WAG1, which phosphorylates PIN2 in vitro6 and is transcriptionally upregulated specifically in dividing cells, as a crucial regulator of post-cytokinetic PIN2 polarity re-establishment.},
  author       = {Glanc, Matous and Fendrych, Matyas and Friml, Jirí},
  issn         = {2055-0278},
  journal      = {Nature Plants},
  number       = {12},
  pages        = {1082--1088},
  publisher    = {Nature Research},
  title        = {{Mechanistic framework for cell-intrinsic re-establishment of PIN2 polarity after cell division}},
  doi          = {10.1038/s41477-018-0318-3},
  volume       = {4},
  year         = {2018},
}