Figure 1.

Rags localize to the lysosome surface and serve as a signaling scaffold for mTORC1 activation in response to cellular nutrient levels. Under nutrient rich conditions, Rags promote mTORC1 lysosomal localization where it is activated and promotes an anabolic signaling environment to promote cellular growth and proliferation. Under conditions of low nutrient availability, mTORC1 dissociates from the Rags at the lysosome surface and the cell switches to a catabolic metabolic program featuring increased autophagy and lysosome biogenesis, which serves to restore cellular nutrient pools.