10.1038/s41598-018-28188-1 Grones, Peter Peter Grones Abas, Melinda F Melinda F Abas Hajny, Jakub Jakub Hajny Jones, Angharad Angharad Jones Waidmann, Sascha Sascha Waidmann Kleine Vehn, Jürgen Jürgen Kleine Vehn Friml, Jirí Jirí Friml0000-0002-8302-7596 PID/WAG-mediated phosphorylation of the Arabidopsis PIN3 auxin transporter mediates polarity switches during gravitropism Springer 2018 2018-12-11T11:45:06Z 2019-01-24T13:05:25Z journal_article https://research-explorer.app.ist.ac.at/record/191 https://research-explorer.app.ist.ac.at/record/191.json 2413876 bytes application/pdf Intercellular distribution of the plant hormone auxin largely depends on the polar subcellular distribution of the plasma membrane PIN-FORMED (PIN) auxin transporters. PIN polarity switches in response to different developmental and environmental signals have been shown to redirect auxin fluxes mediating certain developmental responses. PIN phosphorylation at different sites and by different kinases is crucial for PIN function. Here we investigate the role of PIN phosphorylation during gravitropic response. Loss- and gain-of-function mutants in PINOID and related kinases but not in D6PK kinase as well as mutations mimicking constitutive dephosphorylated or phosphorylated status of two clusters of predicted phosphorylation sites partially disrupted PIN3 phosphorylation and caused defects in gravitropic bending in roots and hypocotyls. In particular, they impacted PIN3 polarity rearrangements in response to gravity and during feed-back regulation by auxin itself. Thus PIN phosphorylation, besides regulating transport activity and apical-basal targeting, is also important for the rapid polarity switches in response to environmental and endogenous signals.