Stability and localization of 14-3-3 proteins are involved in salt tolerance in Arabidopsis
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Salt stress induces the degradation of 14-3-3 proteins, and affects the localization of 14-3-3 λ. Both the modulation of 14-3-3 protein stability and the subcellular localization of these proteins are involved in salt tolerance in plants.
Salt tolerance in plants is regulated by multiple signaling pathways, including the salt overly sensitive (SOS) pathway, of which the SOS2 protein is a key component. SOS2 is activated under salt stress to enhance salt tolerance in plants. We previously identified 14-3-3 λ and κ as important regulators of salt tolerance. Both proteins interact with SOS2 to inhibit its kinase activity under normal growth conditions. In response to salt stress, 14-3-3 proteins dissociate from SOS2, releasing its activity and activating the SOS pathway to confer salt tolerance (Zhou et al. Plant Cell 26:1166–1182, 2014). Here we report that salt stress promotes the degradation of 14-3-3 λ and κ, at least in part via the actions of SOS3-like calcium binding protein 8/calcineurin-B-like10, and also decreases the plasma membrane (PM) localization of 14-3-3 λ. Salt stress also partially represses the interaction of SOS2 and 14-3-3 λ at the PM, but activates PM-localized SOS2. Together, these results suggest that, in plants, both the modulation of 14-3-3 stability and the subcellular localization of these proteins in response to salt stress are important for SOS2 activation and salt tolerance. These data provide new insights into the biological roles of 14-3-3 proteins in modulating salt tolerance.
KeywordsSalt tolerance SOS pathway 14-3-3 proteins Ubiquitination Stability Subcellular localization
We thank Dr. Honghui Lin, Dr. Dehui Xi, and Dr. Dawei Zhang from Sichuan University for their critical reading of the manuscript and their stimulating discussions; and Chongwu Wang, Changxi Chen, Yuan Xue, and Jianfang Li from China Agricultural University for their excellent technical assistance. This work was supported by the Sichuan University Start-Up Funding to H.Z.
H.Z. and Y.G. designed the research. T.T., J.C., E.Z., and H.Z. performed most of the research. T.T. and H.Z. analyzed the data. J.Z. and Y.Y. performed the research on the analysis of cytosol/PM isolation. Y.G. and H.Z. contributed to the discussion and wrote the article.
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