The Legionella Effector Protein DrrA AMPylates the Membrane Traffic Regulator Rab1b

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Science  22 Jul 2010:
DOI: 10.1126/science.1192276


In the course of Legionnaires’ disease, the bacterium Legionella pneumophila affects the intracellular vesicular trafficking of infected eukaryotic cells by recruiting the small guanosine triphosphatase (GTPase) Rab1 to the cytosolic face of the Legionella-containing vacuole (LCV). In order to accomplish this, the Legionella protein DrrA contains a specific guanine nucleotide exchange activity for Rab1 activation that exchanges guanosine triphosphate (GTP) for guanosine diphosphate (GDP) on Rab1. Here, we found that the N-terminal domain of DrrA has AMPylation activity toward the switch II region of Rab1b, which leads to posttranslational covalent modification of tyrosine 77. AMPylation of switch II by DrrA restricts the access of GTPase-activating proteins, which renders Rab1b constitutively active.