Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158.
HHMI, University of California, San Francisco, CA 94158.
Proc Natl Acad Sci U S A. 2022 Sep 20;119(38):e2204083119. doi: 10.1073/pnas.2204083119. Epub 2022 Sep 12.
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 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 .
哺乳动物雷帕霉素靶蛋白（mTOR）是一种高度保守的真核蛋白激酶，它协调细胞生长和代谢，在癌症、免疫和衰老中发挥着关键作用。目前尚不清楚单个组织中的 mTOR 信号如何对整个器官过程产生影响，因为 mTOR 抑制剂（如天然产物雷帕霉素）是全身性给药的，同时靶向多个组织。我们开发了一种化学遗传学系统，称为 selecTOR，通过靶向表达突变型 FKBP12 蛋白，将雷帕霉素类似物的活性限制在特定的细胞群体中。这种类似物与它的必需结合伴侣 FKBP12 的亲和力降低，从而降低了它在野生型细胞和组织中抑制 mTOR 的能力。含有扩展结合口袋的突变型 FKBP12 的表达挽救了这种雷帕霉素类似物的活性。使用该系统，我们证明了在 和人类细胞中可以实现选择性 mTOR 抑制，并且通过鉴定在 中导致雷帕霉素诱导的发育延迟的组织，验证了我们系统在完整后生动物模式生物中的实用性。
