Raptor
Defining subunit of mTORC1; scaffold that presents substrates (S6K1, 4E-BP1) to mTOR. Its presence is what makes a complex 'mTORC1'.
The part that makes mTOR into mTORC1.
Recognises TOS motifs; the AMPK phosphorylation site and the Rag-binding surface both sit here, so Raptor is where location and inhibition converge.
Evidence at a glance
| Evidence | What it means | Studies |
|---|---|---|
| M | Molecular — cells, biochemistry, structure | 7 |
No direct human evidence in the Atlas for this entity yet — everything below rests on animal or molecular work.
Studies
| Year | Evidence | Study |
|---|---|---|
| 2008 | M | AMPK phosphorylation of raptor mediates a metabolic checkpoint GWI2008 Found a SECOND way the energy sensor AMPK shuts mTORC1 down. Besides acting through TSC2, AMPK directly phosphorylates Raptor - the core mTORC1 subunit - to halt growth when energy runs low. This 'metabolic checkpoint' is exactly the switch that drugs like metformin and exercise tap into. |
| 2007 | M | PRAS40 is an insulin-regulated inhibitor of the mTORC1 protein kinase SAN2007 Identified PRAS40 as the missing insulin-controlled brake INSIDE mTORC1. When insulin is absent PRAS40 clamps the complex shut; insulin makes Akt phosphorylate PRAS40, releasing the brake so Rheb can fully switch mTORC1 on. Explained how hormone signals set the exact strength of mTORC1 activity. |
| 2007 | M | mTOR controls mitochondrial oxidative function through a YY1-PGC-1alpha transcriptional complex CUN2007 Showed mTOR isn't just about building proteins - it also runs the cell's POWER plants. mTORC1 drives mitochondrial gene expression and oxygen consumption through a YY1-PGC-1alpha transcriptional program; block mTOR with rapamycin and mitochondrial output falls. Explains part of why mTOR inhibition reshapes metabolism. |
| 2006 | M | Ablation in mice of the mTORC components raptor, rictor, or mLST8 reveals that mTORC2 is required for signaling to Akt-FOXO and PKCalpha, but not S6K1 GUE2006 The foundational genetic 'dissection' of the two complexes in living mice. Deleting Raptor was lethal early (mTORC1 essential); deleting Rictor or mLST8 selectively knocked out mTORC2 signaling to Akt and PKCalpha but spared S6K1. This cleanly assigned jobs to each complex and showed mLST8 is an mTORC2-specific requirement in mice. |
| 2003 | M | GbetaL, a positive regulator of the rapamycin-sensitive pathway required for the nutrient-sensitive interaction between raptor and mTOR KIM2003 Discovered mLST8 (GbetaL), the third core subunit that clamps onto mTOR's kinase domain and stabilizes the complex. It fine-tunes how tightly Raptor holds mTOR in response to nutrients - a small but essential cog that later turned out to be especially critical for the mTORC2 complex. |
| 2002 | M | mTOR interacts with raptor to form a nutrient-sensitive complex that signals to the cell growth machinery KIM2002 Discovery of Raptor as the defining partner of mTOR in mTORC1. This is the paper that gives mTORC1 its identity: Raptor is the scaffold that lets mTOR find and phosphorylate its targets (S6K1), and the complex is stabilized under starvation. Companion paper to Hara 2002. |
| 2002 | M | Raptor, a binding partner of target of rapamycin (TOR), mediates TOR action HARA2002 Independent co-discovery of Raptor (same issue of Cell as Kim 2002). Showed Raptor is essential for mTOR to phosphorylate 4E-BP1 and S6K1, and that knocking it down in worms mimics loss of TOR - confirming Raptor as a core, conserved mediator of TOR action. |