Cell
Volume 152, Issue 4, 14 February 2013, Pages 778-790
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Article
mTOR Regulates Lysosomal ATP-Sensitive Two-Pore Na+ Channels to Adapt to Metabolic State

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Summary

Survival in the wild requires organismal adaptations to the availability of nutrients. Endosomes and lysosomes are key intracellular organelles that couple nutrition and metabolic status to cellular responses, but how they detect cytosolic ATP levels is not well understood. Here, we identify an endolysosomal ATP-sensitive Na+ channel (lysoNaATP). The channel is a complex formed by two-pore channels (TPC1 and TPC2), ion channels previously thought to be gated by nicotinic acid adenine dinucleotide phosphate (NAADP), and the mammalian target of rapamycin (mTOR). The channel complex detects nutrient status, becomes constitutively open upon nutrient removal and mTOR translocation off the lysosomal membrane, and controls the lysosome’s membrane potential, pH stability, and amino acid homeostasis. Mutant mice lacking lysoNaATP have much reduced exercise endurance after fasting. Thus, TPCs make up an ion channel family that couples the cell’s metabolic state to endolysosomal function and are crucial for physical endurance during food restriction.

Highlights

► Lysosomes detect ATP concentration via a Na+ channel formed by TPCs and mTOR ► Two-pore channels (TPCs) are not gated by NAADP ► The Na+ channel (lysoNaATP) detects extracellular nutrients via mTOR ► lysoNaATP regulates lysosomal pH stability and the animal’s fasting endurance

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These authors contributed equally to this work