Wu Guangxia, Wang Gang, Ji Jing, Tian Xiaowei, Gao Hailing, Zhao Qing, Li Jing, Wang Yurong
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China.
J Genet. 2014 Aug;93(2):425-30. doi: 10.1007/s12041-014-0396-6.
Plant vacuolar Na(+)/H(+) antiporters play important roles in cellular ion homeostasis,vacuolar pH regulation and sequestration of Na(+) ions into the vacuole. Previous research showed that hydrophilic C-terminal region of Arabidopsis AtNHX1 negatively regulates the Na(+)/H(+) transporting activity. In this study, we truncated the hydrophilic C terminus of a vacuolar Na(+) /H(+) antiporter gene from Salicornia europaea (SeNHX1) to generate its derivative, SeNHX1-ΔC. Expression of SeNHX1 and SeNHX1-ΔC in yeast mutant showed that SeNHX1 significantly improved the tolerance to NaCl; however, the expression of SeNHX1-ΔC enormously decreased the tolerance to NaCl. Overall, these results suggest that the hydrophilic C-terminal region of SeNHX1 is required for Na(+)/H(+) exchanging activity of SeNHX1.
植物液泡Na(+)/H(+)逆向转运蛋白在细胞离子稳态、液泡pH调节以及将Na(+)离子隔离到液泡中发挥着重要作用。先前的研究表明，拟南芥AtNHX1的亲水性C末端区域对Na(+)/H(+)转运活性具有负调控作用。在本研究中，我们截短了欧洲海蓬子液泡Na(+)/H(+)逆向转运蛋白基因（SeNHX1）的亲水性C末端，以产生其衍生物SeNHX1-ΔC。SeNHX1和SeNHX1-ΔC在酵母突变体中的表达表明，SeNHX1显著提高了对NaCl的耐受性；然而，SeNHX1-ΔC的表达极大地降低了对NaCl的耐受性。总体而言，这些结果表明SeNHX1的亲水性C末端区域是SeNHX1的Na(+)/H(+)交换活性所必需的。
