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Phospholipase D-dependent mTOR complex 1 (mTORC1) activation by glutamine.
Elyssa Bernfeld1,2, Deepak Menon1,2, Vishaldeep Vaghela1,3
1From the Departments of Biological Sciences and.
The Journal of Biological Chemistry
|September 9, 2018
Summary
Glutamine activates mTORC1 through phospholipase D and phosphatidic acid, independent of leucine and Rag GTPases. This pathway involves specific GTPases and can be rescued by alpha-ketoglutarate.
Area of Science:
- Cellular metabolism
- Molecular signaling pathways
Background:
- Glutamine is essential for cell proliferation, supporting biosynthesis.
- The mTOR complex 1 (mTORC1) regulates metabolism in response to nutrient availability.
- The precise mechanism of glutamine-mediated mTORC1 activation remains unclear.
Purpose of the Study:
- To elucidate the mechanism by which glutamine activates mTORC1.
- To identify novel nutrient-sensing pathways regulating mTORC1.
Main Methods:
- Investigated glutamine's role in mTORC1 activation.
- Utilized genetic and biochemical approaches to study phospholipase D, phosphatidic acid, and GTPase involvement (Arf1, RalA, Rheb).
Main Results:
- Described a novel leucine- and Rag-independent mTORC1 activation pathway triggered by glutamine.
- Demonstrated that phospholipase D and phosphatidic acid are crucial for glutamine-induced mTORC1 stability and activity.
- Identified Arf1, RalA, and Rheb GTPases as key mediators in this pathway.
- Showed that alpha-ketoglutarate can rescue mTORC1 activation upon glutamine deprivation.
Conclusions:
- Glutamine activates mTORC1 via a distinct phospholipase D-dependent mechanism.
- This pathway provides a novel nutrient input to mTORC1, independent of Rag GTPases and leucine.
- The findings reveal a new layer of metabolic regulation by glutamine.
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