AKT regulates de novo induction of Foxp3

The CD4+Foxp3+ regulatory T cells play an essential role in maintaining tolerance via their suppressive function on conventional T cells. The intracellular signaling pathways that regulate Foxp3 expression are largely unknown. In this study we describe a novel inhibitory role for AKT in regulating de novo induction of Foxp3 both in vivo and in vitro. A constitutively active allele of AKT significantly diminished TGF- induced Foxp3 induction via a rapamycin-sensitive pathway, establishing a role for the AKT-mTOR axis in Treg cells. Moreover, the observed impairment in Foxp3 induction was paralleled by a selective downmodulation of the imparted Treg transcriptional signature highlighting the importance of the balance of intracellular signals in Treg differentiation . Our results provide a basis for further elucidation of molecular mechanisms that regulate Foxp3 induction and identify AKT as an important negative regulator of this process.

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Haxhinasto S, Mathis D, Benoist C