Host lipidation: a mechanism for spatial regulation of Legionella effectors

Bacterial pathogens have evolved the capacity to translocate proteins into the cytosol of infected cells to manipulate host processes. How do pathogens regulate spatially these bacterial effector proteins once they are released into the host cell? One mechanism, which is used by Legionella and other bacterial pathogens, is to encode effectors that mimic the substrates of eukaryotic lipid transferases. In this review we discuss three membrane-targeting pathways in eukaryotes that are exploited by Legionella and other pathogens-prenylation, palmitoylation, and myristoylation. Lipidation of bacterial substrates primes the effectors for coincidence detection-mediated targeting onto membrane-bound organelles by increasing membrane affinity. Intracellular membrane-targeting strategies that exploit protein fatty acylation and prenylation direct bacterial effectors to compartments where their target substrates reside and thus are critical for effector function.