Antagonistic regulation of PIN phosphorylation by PP2A and PINOID directs auxin flux Journal Article

Author(s): Michniewicz, Marta; Zago, Marcelo K; Abas, Lindy; Weijers, Dolf; Schweighofer, Alois; Meskiene, Irute; Heisler, Marcus G; Ohno, Carolyn; Zhang, Jing; Huang, Fang; Schwab, Rebecca; Weigel, Detlef; Meyerowitz, Elliot M; Luschnig, Christian; Offringa, Remko; Friml, Jiří
Article Title: Antagonistic regulation of PIN phosphorylation by PP2A and PINOID directs auxin flux
Abstract: In plants, cell polarity and tissue patterning are connected by intercellular flow of the phytohormone auxin, whose directional signaling depends on polar subcellular localization of PIN auxin transport proteins. The mechanism of polar targeting of PINs or other cargos in plants is largely unidentified, with the PINOID kinase being the only known molecular component. Here, we identify PP2A phosphatase as an important regulator of PIN apical-basal targeting and auxin distribution. Genetic analysis, localization, and phosphorylation studies demonstrate that PP2A and PINOID both partially colocalize with PINs and act antagonistically on the phosphorylation state of their central hydrophilic loop, hence mediating PIN apical-basal polar targeting. Thus, in plants, polar sorting by the reversible phosphorylation of cargos allows for their conditional delivery to specific intracellular destinations. In the case of PIN proteins, this mechanism enables switches in the direction of intercellular auxin fluxes, which mediate differential growth, tissue patterning, and organogenesis.
Keywords: Mutation; Phenotype; Genotype; Protein Transport; Signal Transduction; Protein Subunits; Recombinant Fusion Proteins; Cell polarity; endosomes; Arabidopsis; Arabidopsis Proteins; Indoleacetic Acids; Membrane Transport Proteins; Plants, Genetically Modified; Seedling; Phosphorylation; Protein-Serine-Threonine Kinases; Meristem; Phosphoprotein Phosphatase
Journal Title: Cell
Volume: 130
Issue 6
ISSN: 0092-8674
Publisher: Cell Press  
Date Published: 2007-09-21
Start Page: 1044
End Page: 1056
DOI: 10.1016/j.cell.2007.07.033
Open access: no