Strange bedfellows expose ancient secrets of autophagy in immunity

Abstract

Autophagy has many roles in immunity, including the control of intracellular microbes by a cell-autonomous mechanism. In this issue of Immunity, Shelly et al. (2009) use VSV infection in Drosophila to show the role of autophagy genes in controlling viruses.

Figure 1. Autophagy in Antiviral Immunity

Induction of autophagy as a cell-autonomous antiviral defense in metazoans may require simultaneous stimulation with PRR agonists and inhibition of the Akt pathway. Autophagy, as demonstrated by Shelly et al. (2009), controls VSV in vivo. This process occurs via viral PAMP-dependent induction of autophagy through a PRR (possibly TLR). Nutritional signals, such as insulin, can counteract autophagy induction by stimulating Akt and Tor (Tor inhibits autophagy), but Shelly et al. (2009) observed that during viral PAMP stimulation of autophagy, Akt pathway was inhibited by an unknown mechanism (dashed line); this could be related to the feedback loops known to exist between Tor targets and Akt function (not depicted).