SLC38A9

Gene/Protein · 8 studies in the Atlas

Lysosomal amino-acid transporter and signaling component; acts as an arginine sensor on the lysosomal membrane. Works together with v-ATPase and Ragulator to relay luminal arginine availability to the Rag GTPases and thereby recruit mTORC1. Loss of SLC38A9 impairs arginine-dependent mTORC1 activation.

A lysosomal arginine sensor and exporter. A transporter on the lysosome membrane that acts as an arginine sensor. Working together with v-ATPase and Ragulator, it relays how much arginine is stored inside the lysosome so the Rag GTPases can recruit and switch on mTORC1. Without it, arginine can't properly activate mTORC1.

Its cytosolic N-terminus binds Rag–Ragulator arginine-dependently; the transport and signalling functions are separable and both matter.

TL;DR. SLC38A9 appears in 8 curated studies in Oliver's mTOR Atlas: 7 at the molecular level (cells, biochemistry, structure); 1 review. No study in people is recorded for it in the Atlas yet. It has 1 interaction in the curated pathway model.

In the pathway model

1 interaction in the curated mTOR pathway model. Each row is a claim with the evidence behind it; the evidence code is the kind of study, not its quality.

Interaction	Mechanism	Evidence	Studies
SLC38A9 activates Rag GTPases mechanism: binding · this link in full · on the map table	SLC38A9 sits in the lysosome's wall, senses arginine inside, and then flips RagA into its "on" shape, telling the Rag proteins there's enough.SLC38A9 sits in the lysosomal membrane and reads arginine on the inside. Arginine-bound SLC38A9 acts as an exchange factor that loads RagA with GTP, switching the Rag dimer on (SHE2018B); it also pumps essential amino acids, including leucine, back out into the cytosol. Holds under: Mammalian cell studies and purified-protein work (REB2015, WAN2015, JUN2015, WYA2017, SHE2018B). Cell and biochemical evidence; whole-animal and human relevance are not tested here. plausible in people, not shown directly · settled in the literature	M	REB2015, WAN2015, JUN2015, WYA2017, SHE2018B

Evidence at a glance

Evidence	What it means	Studies
M	Molecular — cells, biochemistry, structure	7
R	Review — secondary literature, not a new result	1

No direct human evidence in the Atlas for this entity yet — everything below rests on animal or molecular work.

Studies

Year	Evidence	Study
2018	M	Crystal structure of arginine-bound lysosomal transporter SLC38A9 in the cytosol-open state LEI2018 Crystal structure of arginine-bound SLC38A9 reveals the basis of lysosomal arginine sensing.
2018	M	Ragulator and SLC38A9 activate the Rag GTPases through noncanonical GEF mechanisms SHE2018B Ragulator and SLC38A9 each act as an unusual guanine-nucleotide exchange factor on the Rag heterodimer, and together they push it into its active state. Ragulator triggers GTP release from RagC, which unlocks the inactive configuration; arginine-bound SLC38A9 converts RagA from the GDP- to the GTP-loaded state. Boundary: purified proteins and cultured human cells. This is the biochemistry of the switch, not a measurement in tissue.
2017	M	mTORC1 Activator SLC38A9 Is Required to Efflux Essential Amino Acids from Lysosomes and Use Protein as a Nutrient WYA2017 SLC38A9 effluxes essential amino acids (e.g. leucine) from lysosomes to activate mTORC1.
2017	R	The Dawn of the Age of Amino Acid Sensors for the mTORC1 Pathway WOLF2017 Review of the newly discovered amino-acid sensors feeding into mTORC1.
2017	M	Lysosomal cholesterol activates mTORC1 via an SLC38A9-Niemann-Pick C1 signaling complex CAS2017 Establishes lysosomal cholesterol as a nutrient input that drives mTORC1 recruitment and activation at the lysosomal surface. SLC38A9 is required for cholesterol-driven mTORC1 activation through conserved cholesterol-responsive motifs, and does so independently of its arginine-sensing function; NPC1, which exports cholesterol from the lysosome, binds SLC38A9 and restrains mTORC1 through its sterol transport function. Boundary: cell lines and patient-derived fibroblasts, no organismal endpoint.
2015	M	Amino Acid-Dependent mTORC1 Regulation by the Lysosomal Membrane Protein SLC38A9 JUN2015 SLC38A9, a lysosomal membrane protein, mediates amino-acid-dependent mTORC1 activation.
2015	M	SLC38A9 is a component of the lysosomal amino acid sensing machinery that controls mTORC1 REB2015 SLC38A9 is a component of the lysosomal amino-acid sensing machinery controlling mTORC1.
2015	M	Metabolism. Lysosomal amino acid transporter SLC38A9 signals arginine sufficiency to mTORC1 WAN2015 The lysosomal transporter SLC38A9 signals arginine sufficiency to mTORC1.

Related entities

Arginine 4 SAMTOR 1 Leucine 1 Rag GTPases 1 CASTOR1 1 Cholesterol 1 Sestrin2 1 mTORC1 1 Ragulator 1

Cite this page

ShowHide

Barton, O. (2026). SLC38A9 [Entity page]. In Oliver's mTOR Atlas [Data set]. https://mtor-atlas.org/gene/slc38a9/ · Dataset DOI 10.5281/zenodo.22059963

@misc{atlas_gene_slc38a9,
  author       = {Barton, Oliver},
  title        = {{Oliver's mTOR Atlas}: SLC38A9},
  howpublished = {Entity page in a data set},
  year         = {2026},
  url          = {https://mtor-atlas.org/gene/slc38a9/},
  doi          = {10.5281/zenodo.22059963}
}

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