The protein mTOR regulates cell growth and metabolism and thus plays a key role in the development of human disorders. In the cell, this regulatory protein is found in two structurally and functionally distinct protein complexes called mTORC1 and mTORC2. In a recent study, the research group of Prof. Michael Hall from the Biozentrum of the University of Basel has shed light on the role of hepatic mTORC1 in whole body physiology and the relevance for human liver cancers.
Hepatic mTORC1 controls whole body physiology
In mammals, the liver is a key organ that controls whole body physiology in response to nutrients. Hall’s team investigated the role of the nutrient sensor mTORC1 in this process. The researchers were able to show that activation of mTORC1 in the liver of mice reduces not only hepatic lipid metabolism but also locomotor activity and body temperature. Upon investigating the underlying molecular mechanism, they observed that mTORC1 hyperactivation enhances the level of the stress hormone FGF21 by depletion of the amino acid glutamine. Treatment of animals with glutamine reduced the level of FGF21 and thus prevented the physiological impairments.
Cancer treatment with mTORC1 inhibitors
Human cancers often exhibit aberrant mTORC1 signaling and glutamine addiction. “We were excited to see that in human liver tumors mTORC1 signaling correlates with FGF21 expression”, comments cell biologist Dr. Marion Cornu and first author of the study. Moreover, mTORC1 inhibitors such as rapamycin are currently used as immunosuppressive agents and anti-cancer drugs. Thus, the novel findings of Hall’s team provide evidence that treatment of glutamine addicted human cancers with rapamycin might have beneficial effects by blocking tumor growth and by preventing deregulation of whole body physiology.
Hall to receive the Sir Hans Krebs Medal
At the FEBS Congress 2014 in Paris at the end of August, Hall will be presented with the Sir Hans Krebs Medal. In a plenary lecture the awardee Hall will talk about “mTOR signaling in growth and metabolism” including his latest results on the impact of mTORC1 in physiology. The Sir Hans Krebs Medal is awarded annually by the FEBS for “outstanding achievements in Biochemistry and Molecular Biology or related sciences” in recognition of Sir Hans Krebs, a biochemist well known for his identification of the citric acid cycle.
Marion Cornu, Wolfgang Oppliger, Verena Albert, Aaron M. Robitaille, Francesca Trapani, Luca Quagliata, Tobias Fuhrer, Uwe Sauer, Luigi Terracciano, Michael N. Hall. Hepatic mTORC1 controls locomotor activity, body temperature, and lipid metabolism through FGF21. PNAS; published online 31 July 2014.
Contact: Communications, Katrin Bühler