Got Lactobacillus? Commensals Power Growth

Although Lactobacilli are generally considered probiotic agents in metazoans, the underlying molecular mechanisms are largely unknown. In this issue of Cell Host & Microbe, Erkosar et al. (2015) reveal that a Drosophila gut commensal, Lactobacillus plantarum(WJL), promotes animal growth by enhancing the host's capacity for protein degradation.