3jza
From Proteopedia
Crystal structure of human Rab1b in complex with the GEF domain of DrrA/SidM from Legionella pneumophila
Structural highlights
Function[RAB1B_HUMAN] Protein transport. Regulates vesicular transport between the endoplasmic reticulum and successive Golgi compartments.[1] [Q5ZSQ3_LEGPH] Virulence effector that plays a key role in hijacking the host vesicular trafficking by recruiting the small guanosine triphosphatase (GTPase) Rab1 to the cytosolic face of the Legionella-containing vacuole (LCVs). Acts as a GDP-GTP exchange factor (GEF) for the small GTPase Rab1 (RAB1A, RAB1B or RAB1C), thereby converting Rab1 to an active GTP-bound state, leading to the incorporation of Rab1 into LCVs. Also shows RabGDI displacement factor (GDF) activity; however, this probably represents a passive activity following the GEF activity. Also acts as an adenylyltransferase by mediating the addition of adenosine 5'-monophosphate (AMP) to 'Tyr-77' of host RAB1B, thereby rendering RAB1B constitutively active. Also has adenylyltransferase activity towards Rab6 and Rab35. Also displays guanylyltransferase activity by mediating the addition of guanosine 5'-monophosphate (GMP) to host RAB1B in vitro; however such activity remains uncertain in vivo. Specifically binds phosphatidylinositol 4-phosphate (PtdIns(4)P) lipids on the cytosolic surface of the phagosomal membrane shortly after infection.[2] [3] [4] [5] [6] [7] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPrenylated 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. RabGDI displacement by DrrA from Legionella is a consequence of its guanine nucleotide exchange activity.,Schoebel S, Oesterlin LK, Blankenfeldt W, Goody RS, Itzen A Mol Cell. 2009 Dec 25;36(6):1060-72. PMID:20064470[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Homo sapiens | Legionella pneumophila subsp. pneumophila str. philadelphia 1 | Blankenfeldt, W | Goody, R S | Itzen, A | Oesterlin, L K | Schoebel, S | Gdf | Gdi | Gdi displacement factor | Gef | Gtp-binding | Lipoprotein | Membrane | Nucleotide-binding | Prenylation | Protein transport | Rabgdi | Rabgef | Transport protein
