Combinatorial actions of bacterial effectors revealed by exploiting genetic tools in yeast

While yeast has been extensively used as a model system for analysing protein–protein and genetic interactions, in the context of bacterial pathogenesis, the use of yeastbased tools has largely been limited to identifying interactions between pathogen effectors and host targets. In their recent work, Ensminger and colleagues (Urbanus et al, 2016) use the combinatorial power of yeast genetics to systematically screen all known Legionella pneumophila effector proteins for effector–effector interactions. They provide new insights into how bacterial effectors balance host cell perturbation and describe mechanisms used by “metaeffectors” to directly modulate target effector activity.