Gene interactions and pathways from curated databases and text-mining
Proc Natl Acad Sci U S A 2004, PMID: 15342917

Tumor-promoting phorbol esters and activated Ras inactivate the tuberous sclerosis tumor suppressor complex via p90 ribosomal S6 kinase.

Roux, Philippe P; Ballif, Bryan A; Anjum, Rana; Gygi, Steven P; Blenis, John

Tuberous sclerosis complex (TSC) is a genetic disorder caused by mutations in either of the two tumor suppressor genes TSC1 or TSC2, which encode hamartin and tuberin, respectively. Tuberin and hamartin form a complex that inhibits signaling by the mammalian target of rapamycin (mTOR), a critical nutrient sensor and regulator of cell growth and proliferation. Phosphatidylinositol 3-kinase (PI3K) inactivates the tumor suppressor complex and enhances mTOR signaling by means of phosphorylation of tuberin by Akt. Importantly, cellular transformation mediated by phorbol esters and Ras isoforms that poorly activate PI3K promote tumorigenesis in the absence of Akt activation. In this study, we show that phorbol esters and activated Ras also induce the phosphorylation of tuberin and collaborates with the nutrient-sensing pathway to regulate mTOR effectors, such as p70 ribosomal S6 kinase 1 (S6K1). The mitogen-activated protein kinase (MAPK)-activated kinase, p90 ribosomal S6 kinase (RSK) 1, was found to interact with and phosphorylate tuberin at a regulatory site, Ser-1798, located at the evolutionarily conserved C terminus of tuberin. RSK1 phosphorylation of Ser-1798 inhibits the tumor suppressor function of the tuberin/hamartin complex, resulting in increased mTOR signaling to S6K1. Together, our data unveil a regulatory mechanism by which the Ras/MAPK and PI3K pathways converge on the tumor suppressor tuberin to inhibit its function.

Diseases/Pathways annotated by Medline MESH: MAP Kinase Signaling System, Tuberous Sclerosis
Document information provided by NCBI PubMed

Text Mining Data

mTOR signaling → Phosphatidylinositol 3-kinase (PI3K): " Phosphatidylinositol 3-kinase (PI3K) inactivates the tumor suppressor complex and enhances mTOR signaling by means of phosphorylation of tuberin by Akt "

mTOR signaling ⊣ RSK1: " RSK1 phosphorylation of Ser-1798 inhibits the tumor suppressor function of the tuberin/hamartin complex, resulting in increased mTOR signaling to S6K1 "

Manually curated Databases

  • IRef Biogrid Interaction: RPS6KA1 — TSC2 (physical association, affinity chromatography technology)
  • IRef Biogrid Interaction: RPS6KA1 — TSC2 (direct interaction, pull down)
  • IRef Biogrid Interaction: RPS6KA1 — TSC1 (physical association, affinity chromatography technology)
  • IRef Biogrid Interaction: AKT1 — TSC1 (physical association, affinity chromatography technology)
  • IRef Biogrid Interaction: AKT1 — TSC2 (physical association, affinity chromatography technology)
  • IRef Hprd Interaction: TSC2 — MAPK1 (in vivo)
  • IRef Hprd Interaction: TSC2 — MAPK1 (in vitro)
  • IRef Hprd Interaction: TSC2 — RPS6KA1 (in vivo)
  • IRef Hprd Interaction: TSC2 — RPS6KA1 (in vitro)
  • IRef Hprd Interaction: LRPAP1 — MAPK1 (in vitro)
  • IRef Hprd Interaction: MAPK3 — LRPAP1 (in vitro)
  • IRef Hprd Interaction: MAPK3 — TSC2 (in vitro)
  • IRef Hprd Interaction: TSC1 — TSC2 (in vitro)
  • IRef Hprd Interaction: TSC1 — TSC2 (in vivo)
  • IRef Hprd Interaction: TSC1 — TSC2 (two hybrid)
  • NCI Pathway Database mTOR signaling pathway: Erk1-2 (MAPK3/MAPK1) → MEK1-2-active (MAP2K1/MAP2K2) (modification, collaborate)
  • NCI Pathway Database mTOR signaling pathway: Erk1-2 (MAPK3/MAPK1) → Erk1-2-active (MAPK3/MAPK1) (modification, collaborate)
  • NCI Pathway Database mTOR signaling pathway: MEK1-2-active (MAP2K1/MAP2K2) → Erk1-2-active (MAPK3/MAPK1) (modification, activates)
  • NCI Pathway Database mTOR signaling pathway: p90S6K (RPS6KA1) → TSC1/TSC2 complex (TSC1-TSC2) (modification, activates)
    Evidence: mutant phenotype, assay, physical interaction
  • NCI Pathway Database mTOR signaling pathway: RAF1-BRAF (RAF1/BRAF) → MEK1-2-active (MAP2K1/MAP2K2) (modification, activates)
  • NCI Pathway Database mTOR signaling pathway: RAF1-BRAF (RAF1/BRAF) → MEK1-2 (MAP2K1/MAP2K2) (modification, activates)
  • NCI Pathway Database mTOR signaling pathway: MEK1-2-active (MAP2K1/MAP2K2) → MEK1-2 (MAP2K1/MAP2K2) (modification, collaborate)
In total, 23 gene pairs are associated to this article in curated databases