Probing the Function of STAS Domains of the Arabidopsis Sulfate Transporters*
Probing the Function of STAS Domains of the Arabidopsis Sulfate Transporters*
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DOI：
10.1074/jbc.m403248200
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发表时间：
2004-07
影响因子：
4.8
通讯作者：
N. Shibagaki;A. Grossman
中科院分区：
文献类型：
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作者：
N. Shibagaki;A. Grossman
植物和动物的硫酸盐转运蛋白在结构上是保守的，有一个在运输中起作用的氨基末端区域和一个被指定为STAS区域的羧基末端区域。硫酸盐转运蛋白中的STAS结构域与细菌抗Sigma因子拮抗剂有很大的相似性。为了确定STAS结构域是否在控制硫酸盐转运蛋白的活性、稳定性或其在质膜上的定位方面起作用，我们研究了删除或修改拟南芥根中主要的硫酸盐转运蛋白的STAS结构域的效果。海藻转运蛋白1；2和硫酸盐转运蛋白1；1挽救了酵母硫酸盐转运蛋白突变株CP154-7B的蛋氨酸依赖生长表型。其中STAS结构域缺失的Stra1；2的构建体(CP154-STA)导致了不能挽救Δ-7B表型的截短多肽的合成。这些构建体不能挽救突变的表型可能既反映了转运蛋白的低水平细胞积累，也反映了截短的蛋白无法定位到质膜上。将来自其他硫酸盐转运蛋白的STAS结构域融合到SUTER1；2ΔSTAS构建物中，恢复了增加的积累和质膜定位，尽管转化子中硫酸盐吸收的动力学相对于合成野生型SUTER1；2蛋白的转化子发生了显著改变。这些结果表明，无论是直接还是间接，STAS结构域对于促进转运蛋白定位到质膜上是必不可少的，但它似乎也影响转运蛋白催化结构域的动力学性质。
Sulfate transporters in plants and animals are structurally conserved and have an amino-terminal domain that functions in transport and a carboxyl-terminal region that has been designated the STAS domain. The STAS domain in sulfate transporters has significant similarity to bacterial anti-sigma factor antagonists. To determine if the STAS domain has a role in controlling the activity of sulfate transporters, their stability, or their localization to the plasma membrane, we examined the effect of deleting or modifying the STAS domain of dominant sulfate transporters in roots of Arabidopsis thaliana. The A. thaliana Sultr1;2 and Sultr1;1 sulfate transporters rescue the methionine-dependent growth phenotype of the yeast sulfate transporter mutant strain CP154-7B. Constructs of Sultr1;2 in which the STAS domain was deleted (ΔSTAS) resulted in synthesis of a truncated polypeptide that was unable to rescue the CP154-7B phenotype. The inability of these constructs to rescue the mutant phenotype probably reflected both low level cellular accumulation of the transporter and the inability of the truncated protein to localize to the plasma membrane. Fusing the STAS domain from other sulfate transporters to Sultr1;2 ΔSTAS constructs restored elevated accumulation and plasma membrane localization, although the kinetics of sulfate uptake in the transformants were markedly altered with respect to transformants synthesizing wild-type Sultr1;2 protein. These results suggest that the STAS domain is essential, either directly or indirectly, for facilitating localization of the transporters to the plasma membrane, but it also appears to influence the kinetic properties of the catalytic domain of transporters.