Examinando por Autor "Otegui, Marisa S."

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    A novel endosomal sorting complex required for transport (ESCRT) component in arabidopsis thaliana controls cell expansion and development
    (American Society for Biochemistry and Molecular Biology Inc., 2014-02) Reyes, Francisca C.; Buono, Rafael A.; Roschzttardtz, Hannetz; Di Rubbo, Simone; Yeun, Li Huey; Russinova, Eugenia; Otegui, Marisa S.
    ESCRT proteins mediate membrane remodeling and scission events and are essential for endosomal sorting of plasma membrane proteins for degradation. We have identified a novel, plant-specific ESCRT component called PROS (POSITIVE REGULATOR OF SKD1) in Arabidopsis thaliana. PROS has a strong positive effect on the in vitro ATPase activity of SKD1 (also known as Vacuolar Protein Sorting 4 or VPS4), a critical component required for ESCRT-III disassembly and endosomal vesiculation. PROS interacts with both SKD1 and the SKD1-positive regulator LIP5/VTA1. We have identified a putative MIM domain within PROS that mediate the interaction with the MIT domain of SKD1. Interestingly, whereas MIM domains are commonly found at the C terminus of ESCRT-III subunits, the PROS MIM domain is internal. The heterologous expression of PROS in yeast mutant cells lacking Vta1p partially rescues endosomal sorting defects. PROS is expressed in most tissues and cells types in Arabidopsis thaliana. Silencing of PROS leads to reduced cell expansion and abnormal organ growth.
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    Class III Peroxidases PRX01, PRX44, and PRX73 Control Root Hair Growth in Arabidopsis thaliana
    (MDPI, 2022-05-02) Marzol, Eliana; Borassi, Cecilia; Carignani Sardoy, Mariana; Ranocha, Philippe; Aptekmann, Ariel A.; Bringas, Mauro; Pennington, Janice; Paez-Valencia, Julio; Martínez Pacheco, Javier; Rodríguez-Garcia, Diana R.; Rondón Guerrero, Yossmayer Del Carmen; Peralta, Juan Manuel; Fleming, Margaret; Mishler-Elmore, John W.; Mangano, Silvina; Blanco-Herrera, Francisca; Bedinger, Patricia A.; Dunand, Christophe; Capece, Luciana; Nadra, Alejandro D.; Held, Michael; Otegui, Marisa S.; Estevez, José M.
    Root hair cells are important sensors of soil conditions. They grow towards and absorb water-soluble nutrients. This fast and oscillatory growth is mediated by continuous remodeling of the cell wall. Root hair cell walls contain polysaccharides and hydroxyproline-rich glycoproteins, including extensins (EXTs). Class-III peroxidases (PRXs) are secreted into the apoplastic space and are thought to trigger either cell wall loosening or polymerization of cell wall components, such as Tyr-mediated assembly of EXT networks (EXT-PRXs). The precise role of these EXT-PRXs is unknown. Using genetic, biochemical, and modeling approaches, we identified and characterized three root-hair-specific putative EXT-PRXs, PRX01, PRX44, and PRX73. prx01,44,73 triple mutation and PRX44 and PRX73 overexpression had opposite effects on root hair growth, peroxidase activity, and ROS production, with a clear impact on cell wall thickness. We use an EXT fluorescent reporter with contrasting levels of cell wall insolubilization in prx01,44,73 and PRX44-overexpressing background plants. In this study, we propose that PRX01, PRX44, and PRX73 control EXT-mediated cell wall properties during polar expansion of root hair cells. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.