Inverse regulation of SOS1 and HKT1 protein localization and stability by SOS3/CBL4 in Arabidopsis thaliana

• 成果类型: Article
• 署名作者: Gamez-Arjona, Francisco; Park, Hee Jin; Garcia, Elena; Aman, Rashid; Villalta, Irene; Raddatz, Natalia; Carranco, Raul; Ali, Akhtar; Ali, Zahir; Zareen, Shah; De Luca, Anna; Leidi, Eduardo O.; Daniel-Mozo, Miguel; Xu, Zheng-Yi; Albert, Armando; Kim, Woe-Yeon; Pardo, Jose M.; Sanchez-Rodriguez, Clara; Yun, Dae-Jin; Quintero, Francisco J.
• 署名单位: Consejo Superior de Investigaciones Cientificas (CSIC); University of Sevilla; CSIC - Instituto de Bioquimica Vegetal y Fotosintesis (IBVF); University of Sevilla; Swiss Federal Institutes of Technology Domain; ETH Zurich; Konkuk University; Chonnam National University; King Abdullah University of Science & Technology; Universite de Tours; Consejo Superior de Investigaciones Cientificas (CSIC); CSIC - Instituto de Recursos Naturales y Agrobiologia de Sevilla (IRNAS); Consejo Superior de Investigaciones Cientificas (CSIC); CSIC - Instituto de Quimica Fisica Blas Cabrera (IQF-CSIC); Northeast Normal University - China; Gyeongsang National University; Universidad Politecnica de Madrid
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11191
• DOI: 10.1073/pnas.2320657121
• 发表日期: 2024-02-27
• 关键词: overly-sensitive 1; na+/h+ antiporter sos1; salt-stress-response; calcium sensor; tolerance; sodium; expression; athkt1; saline; accumulation

摘要

To control net sodium (Na+) uptake, Arabidopsis plants utilize the plasma membrane (PM) Na+/H+ antiporter SOS1 to achieve Na+ efflux at the root and Na+ loading into the xylem, and the channel - like HKT1;1 protein that mediates the reverse flux of Na+ unloading off the xylem. Together, these opposing transport systems govern the partition of Na+ within the plant yet they must be finely co- regulated to prevent a futile cycle of xylem loading and unloading. Here, we show that the Arabidopsis SOS3 protein acts as the molecular switch governing these Na+ fluxes by favoring the recruitment of SOS1 to the PM and its subsequent activation by the SOS2/SOS3 kinase complex under salt stress, while commanding HKT1;1 protein degradation upon acute sodic stress. SOS3 achieves this role by direct and SOS2- independent binding to previously unrecognized functional domains of SOS1 and HKT1;1. These results indicate that roots first retain moderate amounts of salts to facilitate osmoregulation, yet when sodicity exceeds a set point, SOS3- dependent HKT1;1 degradation switches the balance toward Na+ export out of the root. Thus, SOS3 functionally links and co- regulates the two major Na+ transport systems operating in vascular plants controlling plant tolerance to salinity.