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Published on: October 23, 2018
Raptor and mTOR: subunits of a nutrient-sensitive complex.
1Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA.
Current Topics in Microbiology and Immunology
|October 17, 2003
Summary
A novel protein, regulatory associated protein of mTOR (raptor), is essential for the nutrient-sensing mTOR pathway. Raptor regulates cell growth by associating with mTOR and mediating nutrient-dependent activation of S6K1.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- The mechanistic target of rapamycin (mTOR) pathway is a central regulator of cellular growth, responding to nutrient and hormonal cues.
- mTOR is the target of the FKBP12-rapamycin complex and plays a critical role in controlling cell size and proliferation.
Purpose of the Study:
- To identify and characterize novel components of the mTOR pathway.
- To elucidate the role of a newly discovered protein, raptor, in mTOR signaling and nutrient sensing.
Main Methods:
- Protein interaction studies to identify novel mTOR-binding partners.
- Analysis of raptor's function in nutrient-mediated activation of downstream effectors.
- Investigation of raptor's role in regulating mTOR kinase activity under different nutrient conditions.
Main Results:
- A novel, evolutionarily conserved protein named raptor (regulatory associated protein of mTOR) was identified and found to interact with mTOR.
- Raptor is required for nutrient-mediated activation of S6K1, a key downstream effector of mTOR, and for increases in cell size.
- Under nutrient-repressed conditions, raptor's association with mTOR is enhanced, leading to decreased mTOR kinase activity.
Conclusions:
- Raptor is a critical regulatory component of the mTOR pathway, linking nutrient availability to cellular growth.
- The interaction between raptor and mTOR is dynamic and crucial for modulating mTOR kinase activity in response to nutrient levels.
- Raptor's function highlights a key mechanism by which cells adapt their growth in response to environmental cues.
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