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Friday 23 April 2004

TSC1 signaling pathway

The TSC1-TSC2 complex functions as GTPase activating protein against Rheb - a Ras-like small GTPase, which in turn regulates TOR signaling in nutrient-stimulated cell growth.

TSC1 and TSC2 receive input from several signalling pathways, including the PI3K–Akt (insulin-signalling) pathway, the ERK1/2 pathway, the p38MAPK–MK2 pathway and the LKB1–AMPK (energy-sensing) pathway, as well as GSK3β. Also, there is probably direct input from signalling in response to hypoxia.

In response to these signals, TSC1–2 acts as a GTPase-activating protein (GAP) for Rheb, which, in turn, regulates mTOR. Activated mTOR has two main downstream targets, S6K and 4E-BP1. This process activates cell growth and proliferation.


- germline mutations in tuberous sclerosis
- somatic mutations in tumors

See also

- FRAP1 (mTOR)
- tuberous sclerosis
- Locus TSC2 (MIM.191092) at 16p13.3
- Locus TSC3 at 12q14 (MIM.191091)
- Locus TSC4 (MIM.191090)


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- Fingar DC, Blenis J. Target of rapamycin (TOR): an integrator of nutrient and growth factor signals and coordinator of cell growth and cell cycle progression. Oncogene. 2004 Apr 19;23(18):3151-71. PMID: 15094765

- Pan D, Dong J, Zhang Y, Gao X. Tuberous sclerosis complex: from Drosophila to human disease. Trends Cell Biol. 2004 Feb;14(2):78-85. PMID: 15102439

- Yeung RS. Multiple roles of the tuberous sclerosis complex genes. Genes Chromosomes Cancer. 2003 Dec;38(4):368-75. PMID: 14566857