Related Experiment Video
Updated: May 13, 2026
08:49
Fluorescence-Based Measurements of Phosphatidylserine/Phosphatidylinositol 4-Phosphate Exchange Between Membranes
Published on: March 14, 2021
Phosphatidic acid and lipid-sensing by mTOR
1Department of Biological Sciences, Hunter College of the City University of New York, New York, NY 10065, USA. foster@genectr.hunter.cuny.edu
Trends in Endocrinology and Metabolism: TEM
|March 20, 2013
Summary
Mammalian target of rapamycin (mTOR) senses nutrient sufficiency. New research suggests mTOR also senses lipid precursors, like phosphatidic acid (PA), essential for cell growth and division.
Area of Science:
- Cellular biology
- Biochemistry
- Molecular biology
Background:
- Mammalian target of rapamycin (mTOR) is a key regulator of cell growth, activated by nutrients like amino acids and glucose.
- Cellular division necessitates membrane biosynthesis, which relies on lipids and phospholipid precursors.
- Phosphatidic acid (PA) is a central metabolite in phospholipid synthesis and stabilizes mTOR complexes.
Purpose of the Study:
- To investigate the role of phosphatidic acid (PA) in mammalian target of rapamycin (mTOR) signaling.
- To explore the potential of PA as a sensor for lipid availability for cell growth.
- To understand the evolutionary link between lipid metabolism and mTOR activity.
Main Methods:
- Analysis of PA generation pathways, including phospholipase D, diacylglycerol kinases, and lysophosphatidic acid acyltransferases.
- Investigating the interaction between PA and mTOR complexes.
- Reviewing existing literature on nutrient sensing and cell division.
Main Results:
- Phosphatidic acid (PA) is crucial for the stability and activity of mTOR complexes.
- PA is generated through multiple pathways central to phospholipid biosynthesis.
- mTOR's responsiveness to PA suggests a role in sensing lipid precursors.
Conclusions:
- The mammalian target of rapamycin (mTOR) pathway is responsive to phosphatidic acid (PA), a key lipid metabolite.
- This responsiveness likely evolved to enable cells to sense lipid availability for membrane synthesis before division.
- mTOR integrates signals of nutrient sufficiency, including lipids, to regulate cell growth and proliferation.
Related Concept Videos
01:22PI3K/mTOR/AKT Signaling Pathway
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast, mTORC2 consists of a rapamycin-insensitive companion...
03:03mTOR Signaling and Cancer Progression
The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
The mTOR pathway or the...
03:03mTOR Signaling and Cancer Progression
The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
The mTOR pathway or the...
01:42Phosphoinositides and PIPs
Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
01:11IP3/DAG Signaling Pathway
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...
01:20The JAK-STAT Signaling Pathway
Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as SH2...