RETRACTED: Death deflected:: IL-15 inhibits TNF-α-mediated apoptosis in fibroblasts by TRAF2 recruitment to the IL-15Rα chain (Retracted Article. See vol 25, pg 1118, 2011)

Interleukin-15 (IL-15) is a potent inhibitor of several apoptosis pathways. One prominent path toward apoptosis is the ligand-induced association of TNF receptor 1 (TNFR1) with death domain adaptor proteins. Studying if and how IL-15 blocks TNFR1-mediated apoptosis in a murine fibroblast cell line (L929), we show here that IL-15 blocks TNFR1-induced apoptosis tia IL-15R alpha chain signaling. The intracellular tail of IL-15R alpha shows sequence homologies to the TRAF2 binding motifs of CD30 and CD40. Most important, binding of IL-15 to IL-15R alpha successfully competes with the TNFR1 complex for TRAF2 binding, which may impede assembly of key adaptor proteins to the TNFR1 complex, and induces I kappa B alpha phosphorylation, Thus, IL-15R alpha chain stimulation is a powerful deflector of cell death very early in the apoptosis signaling cascade, while TNF-alpha and IL-15 surface as major opponents in apoptosis control.