ACS Chem Biol. 2012 Jun 15;7(6):982-7. doi: 10.1021/cb300058v. Epub 2012 Apr 18.
The target of rapamycin (TOR) is a critical regulator of growth, survival, and energy metabolism. The allosteric TORC1 inhibitor rapamycin has been used extensively to elucidate the TOR related signal pathway but is limited by its inability to inhibit TORC2. We used an unbiased cell proliferation assay of a kinase inhibitor library to discover QL-IX-55 as a potent inhibitor of S. cerevisiae growth. The functional target of QL-IX-55 is the ATP-binding site of TOR2 as evidenced by the discovery of resistant alleles of TOR2 through rational design and unbiased selection strategies. QL-IX-55 is capable of potently inhibiting both TOR complex 1 and 2 (TORC1 and TORC2) as demonstrated by biochemical IP kinase assays (IC(50) <50 nM) and cellular assays for inhibition of substrate YPK1 phosphorylation. In contrast to rapamycin, QL-IX-55 is capable of inhibiting TORC2-dependent transcription, which suggests that this compound will be a powerful probe to dissect the Tor2/TORC2-related signaling pathway in yeast.
雷帕霉素靶蛋白（TOR）是生长、存活和能量代谢的关键调节因子。雷帕霉素是一种变构 TORC1 抑制剂，已被广泛用于阐明 TOR 相关信号通路，但由于其不能抑制 TORC2 而受到限制。我们使用激酶抑制剂文库的无偏细胞增殖测定法发现 QL-IX-55 是一种有效的酿酒酵母生长抑制剂。QL-IX-55 的功能靶标是 TOR2 的 ATP 结合位点，这一点通过合理设计和无偏选择策略发现 TOR2 的抗性等位基因得到证明。QL-IX-55 能够强烈抑制 TOR 复合物 1 和 2（TORC1 和 TORC2），这一点通过生化 IP 激酶测定法（IC50<50 nM）和细胞测定法抑制 YPK1 磷酸化底物得到证明。与雷帕霉素不同，QL-IX-55 能够抑制 TORC2 依赖性转录，这表明该化合物将成为在酵母中剖析 Tor2/TORC2 相关信号通路的有力探针。
