RAB1A and infection: Consistent with earlier reports [18], [19], L. pneumophila mutants lacking sidD showed a significantly prolonged colocalization with host cell Rab1 four hours post infection compared to LCVs containing wild type bacteria (36% vs 11% Rab1-positive vacuoles), in agreement with the failure of a sidD deletion strain to de-AMPylate Rab1 and to initiate Rab1 inactivation and removal from the LCV membrane by Rab1GAPs and GDI, respectively.