2j59
From Proteopedia
Crystal structure of the ARF1:ARHGAP21-ArfBD complex
Structural highlights
FunctionARF1_MOUSE GTP-binding protein that functions as an allosteric activator of the cholera toxin catalytic subunit, an ADP-ribosyltransferase. Involved in protein trafficking among different compartments. Modulates vesicle budding and uncoating within the Golgi complex. Deactivation induces the redistribution of the entire Golgi complex to the endoplasmic reticulum, suggesting a crucial role in protein trafficking. In its GTP-bound form, its triggers the association with coat proteins with the Golgi membrane. The hydrolysis of ARF1-bound GTP, which is mediated by ARFGAPs proteins, is required for dissociation of coat proteins from Golgi membranes and vesicles. 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 PubMedARHGAP21 is a Rho family GTPase-activating protein (RhoGAP) that controls the Arp2/3 complex and F-actin dynamics at the Golgi complex by regulating the activity of the small GTPase Cdc42. ARHGAP21 is recruited to the Golgi by binding to another small GTPase, ARF1. Here, we present the crystal structure of the activated GTP-bound form of ARF1 in a complex with the Arf-binding domain (ArfBD) of ARHGAP21 at 2.1 A resolution. We show that ArfBD comprises a PH domain adjoining a C-terminal alpha helix, and that ARF1 interacts with both of these structural motifs through its switch regions and triggers structural rearrangement of the PH domain. We used site-directed mutagenesis to confirm that both the PH domain and the helical motif are essential for the binding of ArfBD to ARF1 and for its recruitment to the Golgi. Our data demonstrate that two well-known small GTPase-binding motifs, the PH domain and the alpha helical motif, can combine to create a novel mode of binding to Arfs. Structural basis for ARF1-mediated recruitment of ARHGAP21 to Golgi membranes.,Menetrey J, Perderiset M, Cicolari J, Dubois T, Elkhatib N, El Khadali F, Franco M, Chavrier P, Houdusse A EMBO J. 2007 Apr 4;26(7):1953-62. Epub 2007 Mar 8. PMID:17347647[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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