Mammalian target of rapamycin (mTOR) is a highly conserved eukaryotic protein kinase that coordinates cell growth and metabolism, and plays a critical role in cancer, immunity, and aging. It remains unclear how mTOR signaling in individual tissues contributes to whole-organism processes because mTOR inhibitors, like the natural product rapamycin, are administered systemically and target multiple tissues simultaneously. We developed a chemical-genetic system, termed selecTOR, that restricts the activity of a rapamycin analog to specific cell populations through targeted expression of a mutant FKBP12 protein. This analog has reduced affinity for its obligate binding partner FKBP12, which reduces its ability to inhibit mTOR in wild-type cells and tissues. Expression of the mutant FKBP12, which contains an expanded binding pocket, rescues the activity of this rapamycin analog. Using this system, we show that selective mTOR inhibition can be achieved in Saccharomyces cerevisiae and human cells, and we validate the utility of our system in an intact metazoan model organism by identifying the tissues responsible for a rapamycin-induced developmental delay in Drosophila .

中文翻译：

---

使用化学遗传学对 mTOR 进行组织限制性抑制

哺乳动物雷帕霉素靶点（mTOR）是一种高度保守的真核蛋白激酶，可协调细胞生长和代谢，在癌症、免疫和衰老中发挥关键作用。目前尚不清楚单个组织中的 mTOR 信号传导如何影响整个生物体过程，因为 mTOR 抑制剂（如天然产物雷帕霉素）是全身给药并同时靶向多个组织。我们开发了一种称为 selectTOR 的化学遗传系统，该系统通过突变 FKBP12 蛋白的靶向表达将雷帕霉素类似物的活性限制在特定细胞群中。该类似物与其专性结合伴侣 FKBP12 的亲和力降低，从而降低了其在野生型细胞和组织中抑制 mTOR 的能力。含有扩大的结合袋的突变体 FKBP12 的表达可以恢复这种雷帕霉素类似物的活性。使用该系统，我们表明可以在以下情况下实现选择性 mTOR 抑制：酿酒酵母和人类细胞，我们通过识别负责雷帕霉素诱导的发育迟缓的组织，验证了我们的系统在完整的后生动物模型生物中的效用。果蝇。