I am investigating how cells fine-tune their metabolism to take advantage of the nutrients available to them. In mammalian cells, a protein kinase known as the mechanistic Target of Rapamycin (mTORC1) acts as a major player, controlling the growth of cells and the organism as a whole. In times of plenty, this protein promotes synthesis of cellular building blocks; when faced with starvation, it prompts the cell to digest itself. But how does mTORC1 gauge whether nutrients are readily available? As a postdoctoral fellow at the Whitehead Institute, I determined that mTORC1 is activated by the lysosome, a subcellular structure that digests material ingested by cells and breaks down damaged cellular components. Now, combining innovative biochemical techniques with advanced microscopy and metabolic studies, my laboratory will explore how lysosomes help to regulate growth and metabolism by providing information about available nutrients—and address how certain cancer cells use this information to benefit their survival. These findings will reveal previously unknown functions of the lysosome and could lead to novel therapeutics for treating cancers.