Legionella pneumophila (LP) secretes more than 300 effectors into the host cytosol to facilitate intracellular replication. One of these effectors, SidH does not have sequence similarityto proteins of known function and is toxic when overexpressed in host cells. In order to understand the mechanism and function, it is important to know what host factors, SidH interacts with in human cells. Using quantitative proteomics, we uncovered multiple host proteins as potential targets of SidH.