title: mTORC1 regulates CD8+ T-cell glucose metabolism and function independently of PI3K and PKB.
abstract: Given that inflammatory T-cells have a highly glycolytic metabolism, whereas regulatory T-cells rely more on oxidative glucose metabolism, there is growing interest in understanding how T-cell metabolism relates to T-cell function. The mTORC1 (mammalian target of rapamycin complex 1) has a crucial role to determine the balance between effector and regulatory T-cell differentiation, but is also described as a key regulator of metabolism in non-immune cell systems. The present review explores the relationship between these diverse functions of mTORC1 with regard to T-cell function. In many cell systems, mTORC1 couples PI3K (phosphoinositide 3-kinase) and PKB (protein kinase B), also known as Akt, with the control of glucose uptake and glycolysis. However, this is not the case in activated CD8+ CTLs (cytotoxic T-lymphocytes) where PI3K/PKB signalling is dispensable for the elevated levels of glycolysis that is characteristic of activated T-cells. Nevertheless, mTORC1 is still essential for glycolytic metabolism in CD8+ T-cells, and this reflects the fact that mTORC1 does not lie downstream of PI3K/PKB signalling in CD8+ T-cells, as is the case in many other cell systems. mTORC1 regulates glucose metabolism in CTLs through regulating the expression of the transcription factor HIF1α (hypoxia-inducible factor 1α). Strikingly, HIF1α functions to couple mTORC1 with a diverse transcriptional programme that extends beyond the control of glucose metabolism to the regulation of multiple key T-cell functions. The present review discusses the idea that mTORC1/HIF1α signalling integrates the control of T-cell metabolism and T-cell function.
authors.affiliation: School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: David K
authors.initials: DK
authors.lastname: Finlay
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000201:enzymology / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*
chemical_list: D005947:Glucose; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases