Sestrin2 is a leucine sensor for the mTORC1 pathway.
Level 5 - mechanism / opinion, no new human data
Bench / in vitro mechanistic research without human clinical data.
PubMed 26449471 · doi:10.1126/science.aab2674
What was done
Investigated how leucine regulates mTOR complex 1 (mTORC1) via Rag GTPases, GATOR1, GATOR2, and Sestrin2. The authors examined whether leucine or arginine binds Sestrin2 to disrupt its interaction with GATOR2, measured the dissociation constant for leucine binding, and tested whether this binding capacity is necessary for mTORC1 activation in cells.
What was found
Leucine (but not arginine) disrupted the Sestrin2-GATOR2 interaction by binding Sestrin2 with a dissociation constant of 20 micromolar, matching the concentration that half-maximally activates mTORC1. The leucine-binding capacity of Sestrin2 was required for leucine-induced mTORC1 activation in cells.
Why it matters
The study identifies Sestrin2 as a direct intracellular sensor for leucine upstream of mTORC1, defining a core molecular link between amino acid availability and cell growth control.
Limits
This is purely basic bench/cellular research with no in vivo animal or human data described in the abstract. Exact cell lines, experimental replicates, and statistical measures are not reported in the abstract.
Cited by
- supports David Sabatini's lab at MIT published a paper in Science crystallizing and identifying the direct leucine sensor for mTORC1.