The kinase mTOR regulates the differentiation of helper T cells through the selective activation of signaling by mTORC1 and mTORC2

Abstract

The kinase mTOR has emerged as an important regulator of helper T cell differentiation. Powell and co-workers show that the mTOR complex mTORC1 selectively regulates TH1 and TH17 differentiation, whereas mTORC2 signaling is required for TH2 differentiation. The kinase mTOR has emerged as an important regulator of the differentiation of helper T cells. Here we demonstrate that differentiation into the TH1 and TH17 subsets of helper T cells was selectively regulated by signaling from mTOR complex 1 (mTORC1) that was dependent on the small GTPase Rheb. Rheb-deficient T cells failed to generate TH1 and TH17 responses in vitro and in vivo and did not induce classical experimental autoimmune encephalomyelitis (EAE). However, they retained their ability to become TH2 cells. Alternatively, when mTORC2 signaling was deleted from T cells, they failed to generate TH2 cells in vitro and in vivo but preserved their ability to become TH1 and TH17 cells. Our data identify mechanisms by which two distinct signaling pathways downstream of mTOR regulate helper cell fate in different ways. These findings define a previously unknown paradigm that links T cell differentiation with selective metabolic signaling pathways.