Arginine
Essential amino acid sensed by two separate routes: cytosolic arginine binds CASTOR1, and lysosomal arginine is read by the transporter-like protein SLC38A9.
A second amino acid the cell counts.
Two-sensor architecture lets the cell distinguish cytosolic from lysosomal arginine pools; the functional division of labour is still argued.
Evidence at a glance
| Evidence | What it means | Studies |
|---|---|---|
| M | Molecular — cells, biochemistry, structure | 5 |
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. |
| 2016 | M | The CASTOR Proteins Are Arginine Sensors for the mTORC1 Pathway CHA2016 Identified CASTOR1 as the direct arginine sensor: when arginine binds CASTOR1, it lets go of GATOR2, switching mTORC1 on. Together with Sestrin2 (leucine) this built the picture of mTORC1 as a cell that literally tastes individual amino acids. |
| 2016 | M | Mechanism of arginine sensing by CASTOR1 upstream of mTORC1 SAX2016 CASTOR1 is a direct arginine sensor upstream of mTORC1; structure reveals the arginine-binding mechanism. |
| 2015 | M | Metabolism. Lysosomal amino acid transporter SLC38A9 signals arginine sufficiency to mTORC1 WAN2015 The lysosomal transporter SLC38A9 signals arginine sufficiency to mTORC1. |
| 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. |