Glycosylphosphatidylinositol-anchored Proteins Are Required for the Transport of Detergent-resistant Microdomain-associated Membrane Proteins Tat2p and Fur4p*
Glycosylphosphatidylinositol-anchored Proteins Are Required for the Transport of Detergent-resistant Microdomain-associated Membrane Proteins Tat2p and Fur4p*
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耐洗涤剂微结构域相关膜蛋白 Tat2p 和 Fur4p* 的运输需要糖基磷脂酰肌醇锚定蛋白*
DOI：
10.1074/jbc.m504684200
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发表时间：
2006
影响因子：
4.8
通讯作者：
Y. Jigami
中科院分区：
文献类型：
--
作者：
Michiyo Okamoto;T. Yoko;Mariko Umemura;K. Nakayama;Y. Jigami
在真核细胞中，许多细胞表面蛋白通过糖基磷脂酰肌醇（GPI）部分附着于膜。在酵母中，GPI在细胞壁中甘露糖蛋白的产生中也起重要作用。我们以前分离的GWT 1突变体，并发现GWT 1是必需的肌醇酰化在GPI生物合成途径。在这项研究中，我们分离到一个新的gwt 1突变等位基因，gwt 1 -10，不仅表现出高的温度敏感性，但也低温敏感性。gwt 1 -10细胞显示受损的酰基转移酶活性和GPI与蛋白质的附着，即使在允许的温度下。我们确定了TAT 2，它编码一个高亲和力的色氨酸通透酶，作为一个多拷贝抑制剂的冷敏感性gwt 1 -10细胞。gwt 1 -10细胞在输入色氨酸方面也有缺陷，色氨酸的缺乏导致了低温度敏感性。显微镜观察显示，Tat 2 p不被运输到质膜，但保留在内质网中的gwt 1 -10细胞生长条件下的蛋白质缺乏。我们发现，Tat 2 p是不相关的耐洗涤剂膜（DRM），这是所需的招募Tat 2 p的质膜。Fur 4p是一种位于质膜DRM中的尿嘧啶通透酶，也得到了类似的结果。这些结果表明，GPI锚定的蛋白是所需的招聘膜蛋白Tat 2 p和Fur 4p质膜通过DRM，这表明，一些膜蛋白在细胞中的重新分布，以响应环境和营养条件，由于与DRM的关联是依赖于GPI锚定的蛋白。
In eukaryotic cells many cell surface proteins are attached to the membrane via the glycosylphosphatidylinositol (GPI) moiety. In yeast, GPI also plays important roles in the production of mannoprotein in the cell wall. We previously isolated gwt1 mutants and found that GWT1 is required for inositol acylation in the GPI biosynthetic pathway. In this study we isolated a new gwt1 mutant allele, gwt1-10, that shows not only high temperature sensitivity but also low temperature sensitivity. The gwt1-10 cells show impaired acyltransferase activity and attachment of GPI to proteins even at the permissive temperature. We identified TAT2, which encodes a high affinity tryptophan permease, as a multicopy suppressor of cold sensitivity in gwt1-10 cells. The gwt1-10 cells were also defective in the import of tryptophan, and a lack of tryptophan caused low temperature sensitivity. Microscopic observation revealed that Tat2p is not transported to the plasma membrane but is retained in the endoplasmic reticulum in gwt1-10 cells grown under tryptophan-poor conditions. We found that Tat2p was not associated with detergent-resistant membranes (DRMs), which are required for the recruitment of Tat2p to the plasma membrane. A similar result was obtained for Fur4p, a uracil permease localized in the DRMs of the plasma membrane. These results indicate that GPI-anchored proteins are required for the recruitment of membrane proteins Tat2p and Fur4p to the plasma membrane via DRMs, suggesting that some membrane proteins are redistributed in the cell in response to environmental and nutritional conditions due to an association with DRMs that is dependent on GPI-anchored proteins.