HEAT repeats mediate plasma membrane localization of Tor2p in yeast
HEAT repeats mediate plasma membrane localization of Tor2p in yeast
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DOI：
10.1074/jbc.m007296200
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发表时间：
2000-11-24
影响因子：
4.8
通讯作者：
Hall, MN
中科院分区：
文献类型：
--
作者：
Kunz, J;Schneider, U;Hall, MN
Tor 1 p和Tor 2 p，两个磷脂酰肌醇激酶同源物和免疫抑制药物雷帕霉素在酿酒酵母中的目标，的亚细胞分布进行了分析。我们发现Tor蛋白与膜外周相关。亚细胞分级分离和免疫荧光研究表明，Tor 1 p和Tor 2 p与质膜和第二部分，这是不同的高尔基体，液泡，线粒体和细胞核，并可能代表泡状结构。脉冲追踪实验表明，与质膜和第二室的Tor蛋白的协会是快速的，似乎不涉及内吞，分泌，或高尔基体的液泡运输途径的组件，并且不受免疫抑制药物雷帕霉素。缺失分析表明，Tor 2 p内的两个域独立地介导定位到两个隔室。这些结构域由被认为充当蛋白质-蛋白质相互作用表面的HEAT重复序列组成。因此，我们的研究将Tor蛋白置于其已知下游效应物的作用位点，并表明它们可能是多蛋白复合物的一部分。
The subcellular distribution of Tor1p and Tor2p, two phosphatidylinositol kinase homologs and targets of the immunosuppressive drug rapamycin in Saccharomyces cerevisiae, was analyzed. We found that Tor protein is peripherally associated with membranes. Subcellular fractionation and immunofluorescence studies showed that Tor1p and Tor2p associate with the plasma membrane and a second fraction that is distinct from Golgi, vacuoles, mitochondria, and nucleus and may represent vesicular structures. Pulse-chase experiments showed that association of Tor protein with plasma membrane and the second compartment is fast, does not appear to involve components of endocytic, secretory, or Golgi to vacuole transport pathways, and is not affected by the immunosuppressive drag rapamycin. Deletion analysis reveals that two domains within Tor2p independently mediate localization to both compartments. These domains are composed of HEAT repeats that are thought to act as protein-protein interaction surfaces. Our studies therefore place Tor proteins at the site of action of their known downstream effecters and suggest that they may be part of a multiprotein complex.