Abstract
Recently, autophagy has emerged as a critical process in the control of T-cell homeostasis. Given the pivotal role of NF-kappaB in the signaling events of T cells, we have analyzed and unveiled a conserved NF-kappaB binding site in the promoter of the murine and human BECN1 autophagic gene (Atg6). Accordingly, we demonstrate that the NF-kappaB family member p65/RelA upregulates BECN1 mRNA and protein levels in different cellular systems. Moreover, p65-mediated upregulation of BECN1 is coupled to increased autophagy. The newly identified kappaB site in the BECN1 promoter specifically interacts with p65 both in vitro and in living Jurkat cells upon phorbol myristate acetate (PMA)-ionomycin stimulation, where p65 induction is coupled to BECN1 upregulation and autophagy induction. Finally, anti-CD3- and PMA-ionomycin-mediated activation of T-cell receptor signaling in peripheral T cells from lymph nodes of healthy mice results in an upregulation of BECN1 expression that can be blocked by the NF-kappaB inhibitor BAY 11-7082. Altogether, these data suggest that autophagy could represent a novel route modulated by p65 to regulate cell survival and control T-cell homeostasis.