AIMTOR is a genetically encoded BRET biosensor that reads out mTOR activity live in single cells and in specific subcellular compartments (cytosol, lysosome surface, nucleus, near mitochondria) -- the enabling technology that makes pulsatile/oscillatory mTOR hypotheses experimentally testable rather than purely theoretical.
| Evidence tier | D Mechanistic / in vitro / review |
| Study type | 5 - Mechanistic / In Vitro |
| Model system | HEK293 cells; primary hippocampal neurons and muscle cells (mouse); biosensor tool |
| Journal | BMC Biology |
| Year | 2020 |
| Peer reviewed | Yes |
| Source | DOI 10.1186/s12915-020-00790-8 · PMID 32620110 · Free full text (PMC7334845) |
mTOR signaling is an essential nutrient and energetic sensing pathway. Here we describe AIMTOR, a sensitive genetically encoded BRET (Bioluminescent Resonance Energy Transfer) biosensor to study mTOR activity in living cells. As a proof of principle, we show in both cell lines and primary cell cultures that AIMTOR BRET intensities are modified by mTOR activity changes induced by specific inhibitors and activators of mTORC1 including amino acids and insulin. We further engineered several versions of AIMTOR enabling subcellular-specific assessment of mTOR activities. We then used AIMTOR to decipher mTOR signaling in physio-pathological conditions. First, we show that mTORC1 activity increases during muscle cell differentiation and in response to leucine stimulation in different subcellular compartments such as the cytosol and at the surface of the lysosome, the nucleus, and near the mitochondria. Second, in hippocampal neurons, we found that the enhancement of neuronal activity increases mTOR signaling. AIMTOR further reveals mTOR-signaling dysfunctions in neurons from mouse models of autism spectrum disorder. Altogether, our results demonstrate that AIMTOR is a sensitive and specific tool to investigate mTOR-signaling dynamics in living cells and phenotype mTORopathies.
| Intervention | Genetically encoded BRET biosensor (AIMTOR) -- tool, not a drug intervention |
| Target | mTOR activity (live, subcellular) |
| Model | Human (HEK293); mouse (neurons, muscle) |
| Effect | Enables real-time single-cell/subcellular measurement of mTOR activity dynamics |