title: RabGDI displacement by DrrA from Legionella is a consequence of its guanine nucleotide exchange activity.
abstract: Prenylated Rab proteins exist in the cytosol as soluble, high-affinity complexes with GDI that need to be disrupted for membrane attachment and targeting of Rab proteins. The Legionella pneumophila protein DrrA displaces GDI from Rab1:GDI complexes, incorporating Rab1 into Legionella-containing vacuoles and activating Rab1 by exchanging GDP for GTP. Here, we present the crystal structure of a complex between the GEF domain of DrrA and Rab1 and a detailed kinetic analysis of this exchange. DrrA efficiently catalyzes nucleotide exchange and mimics the general nucleotide exchange mechanism of mammalian GEFs for Ras-like GTPases. We show that the GEF activity of DrrA is sufficient to displace prenylated Rab1 from the Rab1:GDI complex. Thus, apparent GDI displacement by DrrA is linked directly to nucleotide exchange, suggesting a basic model for GDI displacement and specificity of Rab localization that does not require discrete GDI displacement activity.
authors.affiliation: Department of Physical Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, NRW, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schoebel
authors.forename: Lena Katharina
authors.initials: LK
authors.lastname: Oesterlin
authors.forename: Wulf
authors.initials: W
authors.lastname: Blankenfeldt
authors.forename: Roger Sidney
authors.initials: RS
authors.lastname: Goody
authors.forename: Aymelt
authors.initials: A
authors.lastname: Itzen
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000235:genetics / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006801:Humans; D016952:Legionella pneumophila / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D020761:rab1 GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C101895:DrrA protein, Bacteria; D020730:Guanine Nucleotide Dissociation Inhibitors; D020662:Guanine Nucleotide Exchange Factors; D046912:Multiprotein Complexes; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D020761:rab1 GTP-Binding Proteins