title: Lysine63-linked ubiquitylation of PIN2 auxin carrier protein governs hormonally controlled adaptation of Arabidopsis root growth.
abstract: Cross-talk between plant cells and their surroundings requires tight regulation of information exchange at the plasma membrane (PM), which involves dynamic adjustments of PM protein localization and turnover to modulate signal perception and solute transport at the interface between cells and their surroundings. In animals and fungi, turnover of PM proteins is controlled by reversible ubiquitylation, which signals endocytosis and delivery to the cell's lytic compartment, and there is emerging evidence for related mechanisms in plants. Here, we describe the fate of Arabidopsis PIN2 protein, required for directional cellular efflux of the phytohormone auxin, and identify cis- and trans-acting mediators of PIN2 ubiquitylation. We demonstrate that ubiquitin acts as a principal signal for PM protein endocytosis in plants and reveal dynamic adjustments in PIN2 ubiquitylation coinciding with variations in vacuolar targeting and proteolytic turnover. We show that control of PIN2 proteolytic turnover via its ubiquitylation status is of significant importance for auxin distribution in root meristems and for environmentally controlled adaptations of root growth. Moreover, we provide experimental evidence indicating that PIN2 vacuolar sorting depends on modification specifically by lysine(63)-linked ubiquitin chains. Collectively, our results establish lysine(63)-linked PM cargo ubiquitylation as a regulator of polar auxin transport and adaptive growth responses in higher plants.
authors.affiliation: Department of Applied Genetics and Cell Biology,  University of Natural Resources and Life Sciences (BOKU), 1190 Vienna,  Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Leitner
authors.forename: Jan
authors.initials: J
authors.lastname: Petrášek
authors.forename: Konstantin
authors.initials: K
authors.lastname: Tomanov
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Retzer
authors.forename: Markéta
authors.initials: M
authors.lastname: Pařezová
authors.forename: Barbara
authors.initials: B
authors.lastname: Korbei
authors.forename: Andreas
authors.initials: A
authors.lastname: Bachmair
authors.forename: Eva
authors.initials: E
authors.lastname: Zažímalová
authors.forename: Christian
authors.initials: C
authors.lastname: Luschnig
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology; D005838:Genotype; D018522:Gravitropism / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination / Q000502:physiology*; D014617:Vacuoles / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D008239:Lysine; D044767:Ubiquitin-Protein Ligases; C117013:AT5G57090 protein, Arabidopsis; C572710:RGLG2 protein, Arabidopsis