Phosphatidic acid mediates activation of mTORC1 through the ERK signaling pathway

Jeremiah N. Winter, Todd E. Fox, Mark Kester, Leonard S. Jefferson, Scot R. Kimball

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

The mammalian target of rapamycin (mTOR) assembles into two distinct multiprotein complexes known as mTORC1 and mTORC2. Of the two complexes, mTORC1 acts to integrate a variety of positive and negative signals to downstream targets that regulate cell growth. The lipid second messenger, phosphatidic acid (PA), represents one positive input to mTORC1, and it is thought to act by binding directly to mTOR, thereby enhancing the protein kinase activity of mTORC1. Support for this model includes findings that PA binds directly to mTOR and addition of PA to the medium of cells in culture results in activation of mTORC1. In contrast, the results of the present study do not support a model in which PA activates mTORC1 through direct interaction with the protein kinase but, instead, show that the lipid promotes mTORC1 signaling through activation of the ERK pathway. Moreover, rather than acting directly on mTORC1, the results suggest that exogenous PA must be metabolized to lysophosphatidic acid (LPA), which subsequently activates the LPA receptor endothelial differentiation gene (EDG-2). Finally, in contrast to previous studies, the results of the present study demonstrate that leucine does not act through phospholipase D and PA to activate mTORC1 and, instead, show that the two mediators act through parallel upstream signaling pathways to activate mTORC1. Overall, the results demonstrate that leucine and PA signal through parallel pathways to activate mTORC1 and that PA mediates its effect through the ERK pathway, rather than through direct binding to mTOR.

Original languageEnglish (US)
Pages (from-to)C335-C344
JournalAmerican Journal of Physiology - Cell Physiology
Volume299
Issue number2
DOIs
StatePublished - Aug 1 2010

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Phosphatidic Acids
MAP Kinase Signaling System
Sirolimus
Leucine
Protein Kinases
mechanistic target of rapamycin complex 1
Lysophosphatidic Acid Receptors
Lipids
Multiprotein Complexes
Phospholipase D
Second Messenger Systems
Cell Culture Techniques

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cell Biology

Cite this

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title = "Phosphatidic acid mediates activation of mTORC1 through the ERK signaling pathway",
abstract = "The mammalian target of rapamycin (mTOR) assembles into two distinct multiprotein complexes known as mTORC1 and mTORC2. Of the two complexes, mTORC1 acts to integrate a variety of positive and negative signals to downstream targets that regulate cell growth. The lipid second messenger, phosphatidic acid (PA), represents one positive input to mTORC1, and it is thought to act by binding directly to mTOR, thereby enhancing the protein kinase activity of mTORC1. Support for this model includes findings that PA binds directly to mTOR and addition of PA to the medium of cells in culture results in activation of mTORC1. In contrast, the results of the present study do not support a model in which PA activates mTORC1 through direct interaction with the protein kinase but, instead, show that the lipid promotes mTORC1 signaling through activation of the ERK pathway. Moreover, rather than acting directly on mTORC1, the results suggest that exogenous PA must be metabolized to lysophosphatidic acid (LPA), which subsequently activates the LPA receptor endothelial differentiation gene (EDG-2). Finally, in contrast to previous studies, the results of the present study demonstrate that leucine does not act through phospholipase D and PA to activate mTORC1 and, instead, show that the two mediators act through parallel upstream signaling pathways to activate mTORC1. Overall, the results demonstrate that leucine and PA signal through parallel pathways to activate mTORC1 and that PA mediates its effect through the ERK pathway, rather than through direct binding to mTOR.",
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Phosphatidic acid mediates activation of mTORC1 through the ERK signaling pathway. / Winter, Jeremiah N.; Fox, Todd E.; Kester, Mark; Jefferson, Leonard S.; Kimball, Scot R.

In: American Journal of Physiology - Cell Physiology, Vol. 299, No. 2, 01.08.2010, p. C335-C344.

Research output: Contribution to journalArticle

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