Huang Jing, Zhu Heng, Haggarty Stephen J, Spring David R, Hwang Heejun, Jin Fulai, Snyder Michael, Schreiber Stuart L
Howard Hughes Medical Institute, Harvard Institute of Chemistry and Cell Biology, and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Proc Natl Acad Sci U S A. 2004 Nov 23;101(47):16594-9. doi: 10.1073/pnas.0407117101. Epub 2004 Nov 11.
The TOR (target of rapamycin) proteins play important roles in nutrient signaling in eukaryotic cells. Rapamycin treatment induces a state reminiscent of the nutrient starvation response, often resulting in growth inhibition. Using a chemical genetic modifier screen, we identified two classes of small molecules, small-molecule inhibitors of rapamycin (SMIRs) and small-molecule enhancers of rapamycin (SMERs), that suppress and augment, respectively, rapamycin's effect in the yeast Saccharomyces cerevisiae. Probing proteome chips with biotinylated SMIRs revealed putative intracellular target proteins, including Tep1p, a homolog of the mammalian PTEN (phosphatase and tensin homologue deleted on chromosome 10) tumor suppressor, and Ybr077cp (Nir1p), a protein of previously unknown function that we show to be a component of the TOR signaling network. Both SMIR target proteins are associated with PI(3,4)P2, suggesting a mechanism of regulation of the TOR pathway involving phosphatidylinositides. Our results illustrate the combined use of chemical genetics and proteomics in biological discovery and map a path for creating useful therapeutics for treating human diseases involving the TOR pathway, such as diabetes and cancer.
雷帕霉素靶蛋白（TOR）在真核细胞的营养信号传导中发挥重要作用。雷帕霉素处理会诱导出一种类似于营养饥饿反应的状态，常常导致生长抑制。通过化学遗传学修饰筛选，我们鉴定出两类小分子，即雷帕霉素小分子抑制剂（SMIRs）和雷帕霉素小分子增强剂（SMERs），它们分别抑制和增强雷帕霉素在酿酒酵母中的作用。用生物素化的SMIRs探测蛋白质组芯片揭示了假定的细胞内靶蛋白，包括Tep1p，它是哺乳动物10号染色体缺失的磷酸酶和张力蛋白同源物（PTEN）肿瘤抑制因子的同源物，以及Ybr077cp（Nir1p），一种功能先前未知的蛋白质，我们发现它是TOR信号网络的一个组成部分。这两种SMIR靶蛋白都与PI(3,4)P2相关，提示了一种涉及磷脂酰肌醇的TOR途径调控机制。我们的结果说明了化学遗传学和蛋白质组学在生物学发现中的联合应用，并为开发治疗涉及TOR途径的人类疾病（如糖尿病和癌症）的有用疗法绘制了一条路径。
