Reinke Aaron, Anderson Scott, McCaffery J Michael, Yates John, Aronova Sofia, Chu Stephanie, Fairclough Stephen, Iverson Cory, Wedaman Karen P, Powers Ted
Section of Molecular and Cellular Biology and Center for Genetics and Development, Division of Biological Sciences, University of California, Davis, California 95616, USA.
J Biol Chem. 2004 Apr 9;279(15):14752-62. doi: 10.1074/jbc.M313062200. Epub 2004 Jan 21.
The Tor1p and Tor2p kinases, targets of the therapeutically important antibiotic rapamycin, function as components of two distinct protein complexes in yeast, termed TOR complex 1 (TORC1) and TORC2. TORC1 is responsible for a wide range of rapamycin-sensitive cellular activities and contains, in addition to Tor1p or Tor2p, two highly conserved proteins, Lst8p and Kog1p. By identifying proteins that co-purify with Tor1p, Tor2p, Lst8p, and Kog1p, we have characterized a comprehensive set of protein-protein interactions that define further the composition of TORC1 as well as TORC2. In particular, we have identified Tco89p (YPL180w) and Bit61p (YJL058c) as novel components of TORC1 and TORC2, respectively. Deletion of TOR1 or TCO89 results in two specific and distinct phenotypes, (i) rapamycin-hypersensitivity and (ii) decreased cellular integrity, both of which correlate with the presence of SSD1-d, an allele of SSD1 previously associated with defects in cellular integrity. Furthermore, we link Ssd1p to Tap42p, a component of the TOR pathway that is believed to act uniquely downstream of TORC1. Together, these results define a novel connection between TORC1 and Ssd1p-mediated maintenance of cellular integrity.
Tor1p和Tor2p激酶是具有重要治疗意义的抗生素雷帕霉素的作用靶点，在酵母中作为两种不同蛋白质复合物的组成部分发挥作用，这两种复合物分别称为TOR复合物1（TORC1）和TOR复合物2（TORC2）。TORC1负责多种对雷帕霉素敏感的细胞活动，除Tor1p或Tor2p外，还包含两种高度保守的蛋白质Lst8p和Kog1p。通过鉴定与Tor1p、Tor2p、Lst8p和Kog1p共同纯化的蛋白质，我们确定了一组全面的蛋白质-蛋白质相互作用，进一步明确了TORC1以及TORC2的组成。特别是，我们分别鉴定出Tco89p（YPL180w）和Bit61p（YJL058c）是TORC1和TORC2的新组分。缺失TOR1或TCO89会导致两种特定且不同的表型：（i）对雷帕霉素超敏，（ii）细胞完整性降低，这两种表型均与SSD1-d的存在相关，SSD1-d是SSD1的一个等位基因，此前已发现其与细胞完整性缺陷有关。此外，我们将Ssd1p与Tap42p联系起来，Tap42p是TOR途径的一个组分，被认为仅在TORC1的下游起作用。总之，这些结果确定了TORC1与Ssd1p介导的细胞完整性维持之间的一种新联系。
