mTORC1: turning off is just as important as turning on.

mTORC1 is activated primarily on the lysosome. Menon et al. and Demetriades et al. show that mTORC1 deactivation on the lysosome is determined by recruitment of its negative regulator, the tumor suppressor complex TSC1-TSC2. These reports highlight the importance of subcellular localization in the regulation of mTORC1.