Interaction among Btn1p, Btn2p, and Ist2p reveals potential interplay among the vacuole, amino acid levels, and ion homeostasis in the yeast Saccharomyces cerevisiae
Interaction among Btn1p, Btn2p, and Ist2p reveals potential interplay among the vacuole, amino acid levels, and ion homeostasis in the yeast Saccharomyces cerevisiae
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DOI：
10.1128/ec.4.2.281-288.2005
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发表时间：
2005-02-01
期刊：
影响因子：
--
通讯作者：
Pearce, DA
中科院分区：
文献类型：
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作者：
Kim, Y;Chattopadhyay, S;Pearce, DA
Btn 2 p，一种新的胞质卷曲螺旋蛋白在酿酒酵母，以前被证明是相互作用的，是必要的正确定位的Rhb 1 p，精氨酸摄取的调节剂，和Yif 1 p，高尔基体蛋白。我们现在报告Btn 2 p与Ist 2 p的生物化学和物理相互作用，Ist 2 p是一种被认为具有耐盐功能的质膜蛋白。Btn 2 p（btn 2Delta菌株）的缺失导致不能正确定位Ist 2 p，并且缺乏Btn 2 p和Ist 2 p的菌株（btn 2Delta ist 2Delta菌株）不能在0.5或1.0M NaCl存在下生长。Btn 2 p最初被鉴定为在btn 1Delta菌株中上调，该菌株缺乏液泡-溶酶体膜蛋白Btn 1 p，并作为Batten病的模型。Btn 2 p的这种上调被证明有助于维持btn 1Delta菌株中稳定的液泡pH。随后证明btn 1 p是精氨酸进入液泡的最佳运输所需的。有趣的是，btn 1Delta ist 2Delta菌株也不能在0.5或1.0 M NaCl的存在下生长，ist 2Delta抑制btn 1Delta菌株中的空泡精氨酸转运缺陷。虽然需要进一步的调查，我们推测，改变液泡精氨酸转运btn 1Delta株代表了一种机制，维持或平衡细胞离子稳态。btn 2 p与至少三种蛋白质相互作用，这些蛋白质似乎在不同的亚细胞位置参与不同的生物学功能。由于这些多重相互作用，我们得出结论，Btn 2 p可能发挥调节作用，在整个细胞中的细胞内环境的变化，可能引起的氨基酸水平或pH值的变化，蛋白质运输中断，或离子稳态的不平衡，无论是遗传或环境操纵。
Btn2p, a novel cytosolic coiled-coil protein in Saccharomyces cerevisiae, was previously shown to interact with and to be necessary for the correct localization of Rhb1p, a regulator of arginine uptake, and Yif1p, a Golgi protein. We now report the biochemical and physical interactions of Btn2p with Ist2p, a plasma membrane protein that is thought to have a function in salt tolerance. A deletion in Btn2p (btn2Delta strains) results in a failure to correctly localize Ist2p, and strains lacking Btn2p and Ist2p (btn2Delta ist2Delta strains) are unable to grow in the presence of 0.5 or 1.0 M NaCl. Btn2p was originally identified as being up-regulated in a btn1Delta strain, which lacks the vacuolar-lysosomal membrane protein, Btn1p, and serves as a model for Batten disease. This up-regulation of Btn2p was shown to contribute to the maintenance of a stable vacuolar pH in the btn1Delta strain. Btn1p was subsequently shown to be required for the optimal transport of arginine into the vacuole. Interestingly, btn1Delta ist2Delta strains are also unable to grow in the presence of 0.5 or 1.0 M NaCl, and ist2Delta suppresses the vacuolar arginine transport defect in btn1Delta strains. Although further investigation is required, we speculate that altered vacuolar arginine transport in btn1Delta strains represents a mechanism for maintaining or balancing cellular ion homeostasis. Btn2p interacts with at least three proteins that are seemingly involved in different biological functions in different subcellular locations. Due to these multiple interactions, we conclude that Btn2p may play a regulatory role across the cell in response to alterations in the intracellular environment that may be caused by changes in amino acid levels or pH, a disruption in protein trafficking, or imbalances in ion homeostasis resulting from either genetic or environmental manipulation.