The Salmonella enterica GtgE effector protein contributes to the virulence of this pathogen by modulating trafficking of the Salmonella-containing vacuole. GtgE, which exclusively targets inactive Rab GTPases, has been identified as a cysteine protease with the typical Cys-Hip-Asp catalytic triad. It functions by cleaving the Rab-family GTPases Rab29, Rab32 and Rab38, thereby preventing the delivery of antimicrobial factors to the bacteria-containing vacuole. It has been shown to solely process the inactive GDP-bound GTPase Rab32. However, weak binding of GtgE to the peptide encompassing the Rab29 cleavage site suggests that the function of GtgE may be dependent on other factors, such as a protein partner or interactions with the Salmonella-containing vacuole (SCV) membrane.
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