Related Experiment Video
Updated: Aug 7, 2026
12:17
The 4-vessel Sampling Approach to Integrative Studies of Human Placental Physiology In Vivo
Published on: August 2, 2017
mTOR: a placental growth signaling sensor
H Y Wen1, S Abbasi, R E Kellems
1Department of Biochemistry and Molecular Biology, University of Texas, Houston Medical School, Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA.
Placenta
|April 20, 2005
Summary
Growth factors and nutrients regulate placental development by controlling trophoblast cell proliferation. This study reveals how angiopoietin-2 and glucose activate mammalian target of rapamycin (mTOR) signaling, highlighting mTOR
Area of Science:
- Cell Biology
- Biochemistry
- Reproductive Biology
Background:
- Trophoblast cell proliferation and differentiation are crucial for placental development, influenced by hormones, growth factors, and nutrient availability.
- Intracellular signaling pathways mediating these effects on trophoblast cells remain incompletely understood.
Purpose of the Study:
- To investigate the signaling pathways regulating trophoblast proliferation in response to angiopoietin-2 (Ang-2) and glucose.
- To elucidate the roles of phosphatidylinositol-3 (PI-3) kinase, mammalian target of rapamycin (mTOR), and glutamine fructose-6-phosphate amidotransferase (GFAT) in nutrient and growth factor signaling.
Main Methods:
- Utilized immortalized human trophoblast cells (HTR-8/SVneo).
- Investigated signaling pathways including PI-3 kinase, mTOR, and GFAT in response to Ang-2 and glucose.
- Analyzed the upstream regulation of mTOR by growth factors and nutrients.
Main Results:
- Angiopoietin-2 (Ang-2) induced trophoblast proliferation via PI-3 kinase and mTOR activation.
- Glucose stimulated trophoblast proliferation through mTOR, independent of PI-3 kinase, involving GFAT as a novel nutrient sensor.
- GFAT metabolites acted upstream of mTOR, linking nutrient sensing to trophoblast cell proliferation.
Conclusions:
- Growth factor and nutrient signaling converge at tuberin, an upstream regulator of mTOR.
- mTOR serves as a critical signaling sensor for placental growth.
- This study establishes a novel link between mTOR, GFAT metabolites, and nutrient sensing in trophoblast cell proliferation.
Related Concept Videos
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...
01:24Regulation of Angiogenesis and Blood Supply
Rapidly dividing tumors, embryos, and wounded tissues require more oxygen than usual, lowering the oxygen concentration in the blood. At low oxygen or hypoxic conditions, an oxygen-sensitive transcription factor called the hypoxia-inducible factor 1 or HIF1 is activated. HIF1 is a dimeric protein of alpha (ɑ) and beta (β) subunits. Under optimal oxygen conditions, HIF1β is present in the nucleus while HIF1ɑ remains in the cytosol. HIF1ɑ is hydroxylated by prolyl hydroxylase and factor...
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...
01:16TGF - β Signaling Pathway
The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
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...
01:24Gonadal and Placental Hormones
The gonads, namely the testes in males and the ovaries in females, are pivotal in producing gonadal hormones that orchestrate the intricate processes of sexual development and reproduction.
In males, testosterone is the primary gonadal androgen. It plays a central role in the maturation of male reproductive organs — the penis and testes. Additionally, testosterone is instrumental in the development of secondary sexual characteristics — a deep voice as well as facial and pubic hair growth — and...
In males, testosterone is the primary gonadal androgen. It plays a central role in the maturation of male reproductive organs — the penis and testes. Additionally, testosterone is instrumental in the development of secondary sexual characteristics — a deep voice as well as facial and pubic hair growth — and...