Yeast 14-3-3 proteins participate in the regulation of cell cation homeostasis via interaction with Nha1 alkali-metal-cation/proton antiporter

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• 作者：Jaromí ; r Zahrá ; dka^a ; G. Paul H. van Heusden^b ; Hana Sychrová ; ^a ; ^{sychrova@biomed.cas.cz}
• 关键词：BiFC ; bimolecular fluorescence complementation ; diS-C3(3) ; 3 ; 3&prime ; -dipropylthiacarbocyanide iodide ; YFP ; yellow fluorescent protein
• 刊名：Biochimica et Biophysica Acta (BBA)/General Subjects
• 出版年：2012
• 期刊代码：16_03044165
• 类别：bio
• 出版时间：July, 2012
• 卷：1820
• 期：7
• 页码：849-858
• 文件大小：1243 K

摘要

Background

In yeast, 14-3-3 proteins bind to hundreds of phosphorylated proteins and play a role in the regulation of many processes including tolerance to NaCl. However, the mechanism of 14-3-3 involvement in the cell answer to salt or osmotic stresses is weakly understood.

Methods

We studied the role of the Saccharomyces cerevisiae 14-3-3 homologs Bmh1 and Bmh2 in the regulation of alkali-metal-cation homeostasis using the genetic-interaction approach. Obtained results were confirmed with the Bimolecular-Fluorescence-Complementation method.

Results

Deletion of BMH1, encoding the major 14-3-3 isoform, resulted in an increased sensitivity to Na⁺, Li⁺ and K⁺ and to cationic drugs but did not affect membrane potential. This bmh1螖 phenotype was complemented by overexpression of BMH2. Testing the genetic interaction between BMH genes and genes encoding plasma-membrane cation transporters revealed, that 14-3-3 proteins neither interact with the potassium uptake systems, nor with the potassium-specific channel nor with the Na⁺(K⁺)-ATPases. Instead, a genetic interaction was identified between BMH1 and NHA1 which encodes an Na⁺(K⁺)/H⁺ antiporter. In addition, a physical interaction between 14-3-3 proteins and the Nha1 antiporter was shown. This interaction does not depend on the phosphorylation of the Nha1 antiporter by Hog1 kinase. Our results uncovered a previously unknown interaction partner of yeast 14-3-3 proteins and provided evidence for the previously hypothesized involvement of Bmh proteins in yeast salt tolerance.

General significance

Our results showed for the first time that the yeast 14-3-3 proteins and an alkali-metal-cation efflux system interact and that this interaction enhances the cell survival upon salt stress.