title: C2-domain abscisic acid-related proteins mediate the interaction of PYR/PYL/RCAR abscisic acid receptors with the plasma membrane and regulate abscisic acid sensitivity in Arabidopsis.
abstract: Membrane-delimited abscisic acid (ABA) signal transduction plays a critical role in early ABA signaling, but the molecular mechanisms linking core signaling components to the plasma membrane are unclear. We show that transient calcium-dependent interactions of PYR/PYL ABA receptors with membranes are mediated through a 10-member family of C2-domain ABA-related (CAR) proteins in Arabidopsis thaliana. Specifically, we found that PYL4 interacted in an ABA-independent manner with CAR1 in both the plasma membrane and nucleus of plant cells. CAR1 belongs to a plant-specific gene family encoding CAR1 to CAR10 proteins, and bimolecular fluorescence complementation and coimmunoprecipitation assays showed that PYL4-CAR1 as well as other PYR/PYL-CAR pairs interacted in plant cells. The crystal structure of CAR4 was solved, which revealed that, in addition to a classical calcium-dependent lipid binding C2 domain, a specific CAR signature is likely responsible for the interaction with PYR/PYL receptors and their recruitment to phospholipid vesicles. This interaction is relevant for PYR/PYL function and ABA signaling, since different car triple mutants affected in CAR1, CAR4, CAR5, and CAR9 genes showed reduced sensitivity to ABA in seedling establishment and root growth assays. In summary, we identified PYR/PYL-interacting partners that mediate a transient Ca(2+)-dependent interaction with phospholipid vesicles, which affects PYR/PYL subcellular localization and positively regulates ABA signaling.
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain.
authors.forename: Lesia
authors.initials: L
authors.lastname: Rodriguez
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain.
authors.forename: Miguel
authors.identifier: http://orcid.org/0000-0003-1000-9255
authors.initials: M
authors.lastname: Gonzalez-Guzman
authors.affiliation: Instituto de Química Física Rocasolano, Consejo Superior de Investigaciones Científicas, ES-28006 Madrid, Spain.
authors.forename: Maira
authors.initials: M
authors.lastname: Diaz
authors.affiliation: Instituto Politécnico de Leiria, Escola Superior de Turismo e Tecnologia do Mar, 2411-901 Peniche, Portugal.
authors.forename: Americo
authors.initials: A
authors.lastname: Rodrigues
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Izquierdo-Garcia
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Peirats-Llobet
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Fernandez
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain.
authors.forename: Regina
authors.initials: R
authors.lastname: Antoni
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation and Unit of Virus Host-Cell Interactions, UJF-EMBL-CNRS, 38042 Grenoble Cedex 9, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Fernandez
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation and Unit of Virus Host-Cell Interactions, UJF-EMBL-CNRS, 38042 Grenoble Cedex 9, France.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Marquez
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Mulet
authors.affiliation: Instituto de Química Física Rocasolano, Consejo Superior de Investigaciones Científicas, ES-28006 Madrid, Spain.
authors.forename: Armando
authors.initials: A
authors.lastname: Albert
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain pedrorodriguezegea@gmail.com.
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Rodriguez
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008958:Models, Molecular; D010937:Plant Growth Regulators / Q000494:pharmacology*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D011956:Receptors, Cell Surface; D000040:Abscisic Acid