Location-specific inhibition of Akt reveals regulation of mTORC1 activity in the nucleus

• Published in: Nature communications 2020-11, Vol.11 (1), p.6088-6088, Article 6088
• Main Authors: Zhou, Xin, Zhong, Yanghao, Molinar-Inglis, Olivia, Kunkel, Maya T., Chen, Mingyuan, Sun, Tengqian, Zhang, Jiao, Shyy, John Y.-J., Trejo, JoAnn, Newton, Alexandra C., Zhang, Jin
• Format: Article
• Language: English
• Subjects: 13/1; 14/10; 14/19; 14/35; 14/63; 38/70; 631/80/642/1363; 631/80/86/2368; 631/92/275; 96/106; 96/109; 96/33; 96/95; AKT protein; Animals; Cell Nucleus - metabolism; Energy balance; Gene Knockdown Techniques; Growth factors; HEK293 Cells; Humanities and Social Sciences; Humans; Kinases; Localization; Mechanistic Target of Rapamycin Complex 1 - metabolism; Metabolism; Mice; multidisciplinary; NIH 3T3 Cells; Nuclear transport; Nuclei (cytology); Nutrient status; Occupancy; Phosphoproteins - genetics; Phosphoproteins - metabolism; Protein Kinase Inhibitors - pharmacology; Proto-Oncogene Proteins c-akt - metabolism; Rapamycin; Regulation; Scaffolding; Science; Science (multidisciplinary); Signal Transduction - drug effects; Substrates; TOR protein; TOR Serine-Threonine Kinases - metabolism; Translocation
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-19937-w

The mechanistic target of rapamycin complex 1 (mTORC1) integrates growth, nutrient and energy status cues to control cell growth and metabolism. While mTORC1 activation at the lysosome is well characterized, it is not clear how this complex is regulated at other subcellular locations. Here, we combine location-selective kinase inhibition, live-cell imaging and biochemical assays to probe the regulation of growth factor-induced mTORC1 activity in the nucleus. Using a nuclear targeted Akt Substrate-based Tandem Occupancy Peptide Sponge (Akt-STOPS) that we developed for specific inhibition of Akt, a critical upstream kinase, we show that growth factor-stimulated nuclear mTORC1 activity requires nuclear Akt activity. Further mechanistic dissection suggests that nuclear Akt activity mediates growth factor-induced nuclear translocation of Raptor, a regulatory scaffolding component in mTORC1, and localization of Raptor to the nucleus results in nuclear mTORC1 activity in the absence of growth factor stimulation. Taken together, these results reveal a mode of regulation of mTORC1 that is distinct from its lysosomal activation, which controls mTORC1 activity in the nuclear compartment. The role of mTORC1 at the lysosome is well established, but mTORC1 is known to be active in other cellular locations. Here, the authors develop Akt-STOPS to inhibit Akt specifically in the nucleus and identify a new regulatory mode for mTORC1 distinct in the nucleus.