TY - JOUR A1 - Tejos, Ricardo A1 - Rodriguez-Furlan, Cecilia A1 - Adamowski, Maciej A1 - Sauer, Michael A1 - Norambuena, Lorena A1 - Friml, Jiri T1 - PATELLINS are regulators of auxin-mediated PIN1 relocation and plant development in Arabidopsis thaliana JF - Journal of cell science N2 - Coordinated cell polarization in developing tissues is a recurrent theme in multicellular organisms. In plants, a directional distribution of the plant hormone auxin is at the core of many developmental programs. A feedback regulation of auxin on the polarized localization of PIN auxin transporters in individual cells has been proposed as a self-organizing mechanism for coordinated tissue polarization, but the molecular mechanisms linking auxin signalling to PIN-dependent auxin transport remain unknown. We used a microarray-based approach to find regulators of the auxin-induced PIN relocation in Arabidopsis thaliana root, and identified a subset of a family of phosphatidylinositol transfer proteins (PITPs), the PATELLINs (PATLs). Here, we show that PATLs are expressed in partially overlapping cell types in different tissues going through mitosis or initiating differentiation programs. PATLs are plasma membrane-associated proteins accumulated in Arabidopsis embryos, primary roots, lateral root primordia and developing stomata. Higher order patl mutants display reduced PIN1 repolarization in response to auxin, shorter root apical meristem, and drastic defects in embryo and seedling development. This suggests that PATLs play a redundant and crucial role in polarity and patterning in Arabidopsis. KW - PATELLIN KW - Auxin KW - Arabidopsis thaliana KW - Auxin transport KW - Canalization Y1 - 2018 U6 - https://doi.org/10.1242/jcs.204198 SN - 0021-9533 SN - 1477-9137 VL - 131 IS - 2 PB - Company of Biologists Limited CY - Cambridge ER - TY - JOUR A1 - Sauer, Michael A1 - Kleine-Vehn, Jürgen T1 - PIN-FORMED and PIN-LIKES auxin transport facilitators JF - Development : Company of Biologists N2 - The phytohormone auxin influences virtually all aspects of plant growth and development. Auxin transport across membranes is facilitated by, among other proteins, members of the PIN-FORMED (PIN) and the structurally similar PIN-LIKES (PILS) families, which together govern directional cell-to-cell transport and intracellular accumulation of auxin. Canonical PIN proteins, which exhibit a polar localization in the plasma membrane, determine many patterning and directional growth responses. Conversely, the less-studied noncanonical PINs and PILS proteins, which mostly localize to the endoplasmic reticulum, attenuate cellular auxin responses. Here, and in the accompanying poster, we provide a brief summary of current knowledge of the structure, evolution, function and regulation of these auxin transport facilitators. KW - Auxin KW - Auxin transport KW - Phytohormone Y1 - 2019 U6 - https://doi.org/10.1242/dev.168088 SN - 0950-1991 SN - 1477-9129 VL - 146 IS - 15 PB - Company biologists ltd CY - Cambridge ER - TY - JOUR A1 - Robert, Helene S. A1 - Grunewald, Wim A1 - Sauer, Michael A1 - Cannoot, Bernard A1 - Soriano, Mercedes A1 - Swarup, Ranjan A1 - Weijers, Dolf A1 - Bennett, Malcolm A1 - Boutilier, Kim A1 - Friml, Jiri T1 - Plant embryogenesis requires AUX/LAX-mediated auxin influx JF - Development : Company of Biologists N2 - The plant hormone auxin and its directional transport are known to play a crucial role in defining the embryonic axis and subsequent development of the body plan. Although the role of PIN auxin efflux transporters has been clearly assigned during embryonic shoot and root specification, the role of the auxin influx carriers AUX1 and LIKE-AUX1 (LAX) proteins is not well established. Here, we used chemical and genetic tools on Brassica napus microspore-derived embryos and Arabidopsis thaliana zygotic embryos, and demonstrate that AUX1, LAX1 and LAX2 are required for both shoot and root pole formation, in concert with PIN efflux carriers. Furthermore, we uncovered a positive-feedback loop between MONOPTEROS-(ARF5)dependent auxin signalling and auxin transport. This MONOPTEROS dependent transcriptional regulation of auxin influx (AUX1, LAX1 and LAX2) and auxin efflux (PIN1 and PIN4) carriers by MONOPTEROS helps to maintain proper auxin transport to the root tip. These results indicate that auxin-dependent cell specification during embryo development requires balanced auxin transport involving both influx and efflux mechanisms, and that this transport is maintained by a positive transcriptional feedback on auxin signalling. KW - Arabidopsis thaliana embryogenesis KW - Auxin transport KW - AUX1 KW - LIKE-AUX1 (LAX) KW - MONOPTEROS (ARF5) KW - PIN KW - Brassica napus KW - Microspore Y1 - 2015 U6 - https://doi.org/10.1242/dev.115832 SN - 0950-1991 SN - 1477-9129 VL - 142 IS - 4 SP - 702 EP - 711 PB - Company of Biologists Limited CY - Cambridge ER -