• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Genetic analysis of the Tsc/Rheb/Tor pathway in fission yeast and its involvement in nutrient uptake and drug resistance.
【24h】

Genetic analysis of the Tsc/Rheb/Tor pathway in fission yeast and its involvement in nutrient uptake and drug resistance.

机译：Tsc / Rheb / Tor途径在裂变酵母中的遗传分析及其与养分吸收和耐药性的关系。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The Tsc/Rheb/Tor pathway is a highly conserved signaling cassette involved in the regulation of various cellular processes including cell growth and proliferation. Aberrant regulation of this signal transduction pathway leads to various diseases including Tuberous Sclerosis Complex (TSC), Peutz-Jegher Syndrome (PJS), and is implicated in various cancers as well. Therefore, understanding the interplay between the members of the pathway and finding new phenotypes associated with the pathway may prove insightful into the etiology of these diseases.;Previous studies have suggested that Rheb is involved in the regulation of arginine uptake. However, the mechanism, as well as the role of the upstream and downstream components of Rheb in this process, has not been elucidated. Taking advantage of the genetically malleable organism Schizosaccharomyces pombe, we have found that loss of Tsc2, the Rheb GTPase activating protein (GAP), leads to a defect in the uptake of basic amino acids, which is highlighted by a resistance to toxic analogues of arginine and lysine, canavanine and thialysine, respectively. To further understand this process, we identified the cationic amino acid transporter (CAT) in fission yeast via genetic complementation and disruption in budding yeast and fission yeast, respectively. SPAC869.11 was found to be required for the uptake of basic amino acids and its overexpression in wild type yeast led to an increase in the uptake of basic amino acids and sensitivity to canavanine. SPAC869.11 was thusly dubbed Cat1. Interestingly, loss of Tsc2 affected neither Cat1 RNA nor protein levels, rather, led to a drastic mislocalization of Cat1 from the cell tips to the Golgi apparatus. This mislocalization could be suppressed by the expression of RhebD60K, as well as the introduction of a temperature sensitive Tor2 allele (tor2ts). In addition, we found that loss of the E3 ubiquitin ligase, Pub1, also restores proper localization. On the other hand, loss of Tsc1 and rapamycin treatment of wild type cells leads to an inhibition of arginine uptake and a similar mislocalization of Cat1 to the Golgi albeit not as severe to that of tsc2 - mutants or by overexpression of Tor2. Pub1 is also required for the rapamycin inhibition of arginine uptake. Therefore, it appears that Tor1 and Rheb/Tor2 have counteracting functions that impinge upon Pub1 in the control of Cat1.;We have also found that overactivation of Rheb, either by mutation or loss of Tsc2, leads to the resistance of brefeldin A (BFA) and cerulenin, inhibitors of the Golgi apparatus and fatty acid synthase, respectively. This can be suppressed by a tor2ts mutant as well as by the loss of Pub1. The ABC transporter, Bfr1, is also required for this resistance, and whose protein levels were slightly elevated in tsc2 - mutants. Therefore, it appears that the Tsc/Rheb/Tor pathway controls both the import of amino acids as well as the export of xenobiotics via two different mechanisms.
机译：Tsc / Rheb / Tor途径是高度保守的信号盒，参与各种细胞过程的调控，包括细胞生长和增殖。该信号转导途径的异常调节导致多种疾病，包括结节性硬化症（TSC），Peutz-Jegher综合征（PJS），并且也与多种癌症有关。因此，了解该途径成员之间的相互作用并发现与该途径相关的新表型可能证明对这些疾病的病因学有深刻见识。先前的研究表明，Rheb参与了精氨酸摄取的调节。然而，尚未阐明Rheb的机制以及该过程中上游和下游组分的作用。利用遗传可延展的生物体粟酒裂殖酵母（Schizosaccharomyces pombe），我们发现Rheb GTPase活化蛋白（GAP）Tsc2的丢失导致碱性氨基酸摄取的缺陷，这主要是由于对精氨酸有毒类似物的抵抗力增强分别是赖氨酸，小黄碱和硫赖氨酸。为了进一步了解此过程，我们分别通过遗传互补和在发芽酵母和裂变酵母中的破坏来鉴定裂变酵母中的阳离子氨基酸转运蛋白（CAT）。已发现SPAC869.11是摄取碱性氨基酸所必需的，并且其在野生型酵母中的过表达导致碱性氨基酸的摄取增加以及对canavanine的敏感性。 SPAC869.11因此被称为Cat1。有趣的是，Tsc2的丢失既不影响Cat1 RNA也不影响蛋白质水平，而是导致Cat1从细胞尖端到高尔基体的剧烈错位。 RhebD60K的表达以及引入温度敏感的Tor2等位基因（tor2ts）可以抑制这种定位错误。此外，我们发现E3泛素连接酶Pub1的丢失也恢复了正确的定位。另一方面，Tsc1和雷帕霉素处理野生型细胞的损失会导致精氨酸摄取受到抑制，并且Cat1到高尔基体的错位类似，尽管不如tsc2-突变体严重或通过过表达Tor2引起。雷帕霉素抑制精氨酸摄取也需要Pub1。因此，似乎Tor1和Rheb / Tor2具有抵消在Cat1的控制中影响Pub1的功能。我们还发现，通过突变或Tsc2的缺失，Rheb的过度激活导致布雷菲德菌素A（BFA）的耐药性）和cerulenin，分别是高尔基体的抑制剂和脂肪酸合酶。这可以通过tor2ts突变体以及Pub1的丢失来抑制。 ABC转运蛋白Bfr1对于这种抗性也是必需的，其蛋白水平在tsc2-突变体中略有升高。因此，似乎Tsc / Rheb / Tor途径通过两种不同的机制控制氨基酸的进口以及异源生物的出口。

著录项

  • 作者

    Aspuria, Paul-Joseph Penaflor.;

  • 作者单位

    University of California, Los Angeles.;

  • 授予单位 University of California, Los Angeles.;
  • 学科 Molecular biology.;Immunology.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 128 p.
  • 总页数 128
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号