Beclin 1 modulates the anti-apoptotic activity of Bcl-2: Insights from a pathogen infection system

Abstract

Coxiella burnetii is an obligate intracellular bacterium that generates large vacuoles in which this pathogen replicates and survives. We have previously demonstrated that C. burnetii interacts with the autophagic pathway as a strategy for its survival and replication. Coxiella displays an anti-apoptotic activity to maintain host cell viability, leading to a persistent infection. Our recent study reveals that Beclin 1 is recruited to the Coxiella-membrane vacuole favoring its development and bacterial replication. In contrast, the antiapoptotic protein Bcl-2 alters the normal development of the Coxiella-replicative compartment. In addition, our results indicate that C. burnetii infection modulates autophagy and apoptotic pathways via Beclin 1-Bcl-2 interplay to establish a successful infection in the host cell. Of note, this pathogen-host cell model has allowed uncovering a novel function of Beclin 1 as a regulator of the anti-apoptotic activity of Bcl-2. We have also established that a proper interplay between Beclin 1 and Bcl-2 is required for both autophagy and apoptosis modulation. © 2010 Landes Bioscience.