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Crystal Structure of the DH/PH domains of Leukemia-associated RhoGEFCrystal Structure of the DH/PH domains of Leukemia-associated RhoGEF
Structural highlights
Disease[ARHGC_HUMAN] Note=A chromosomal aberration involving ARHGEF12 may be a cause of acute leukemia. Translocation t(11;11)(q23;23) with MLL. Function[ARHGC_HUMAN] May play a role in the regulation of RhoA GTPase by guanine nucleotide-binding alpha-12 (GNA12) and alpha-13 (GNA13). Acts as guanine nucleotide exchange factor (GEF) for RhoA GTPase and may act as GTPase-activating protein (GAP) for GNA12 and GNA13.[1] 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 PubMedRho guanine-nucleotide exchange factors (RhoGEFs) activate Rho GTPases, and thereby regulate cytoskeletal structure, gene transcription, and cell migration. Leukemia-associated RhoGEF (LARG) belongs to a small subfamily of RhoGEFs that are RhoA-selective and directly activated by the Galpha12/13 family of heterotrimeric G proteins. Herein we describe the atomic structures of the catalytic Dbl homology (DH) and pleckstrin homology (PH) domains of LARG alone and in complex with RhoA. These structures demonstrate that the DH/PH domains of LARG can undergo a dramatic conformational change upon binding RhoA, wherein both the DH and PH domains directly engage RhoA. Through mutational analysis we show that full nucleotide exchange activity requires a novel N-terminal extension on the DH domain that is predicted to exist in a broader family of RhoGEFs that includes p115-RhoGEF, Lbc, Lfc, Net1, and Xpln, and identify regions within the LARG PH domain that contribute to its ability to facilitate nucleotide exchange in vitro. In crystals of the DH/PH-RhoA complex, the active site of RhoA adopts two distinct GDP-excluding conformations among the four unique complexes in the asymmetric unit. Similar changes were previously observed in structures of nucleotide-free Ras and Ef-Tu. A potential protein-docking site on the LARG PH domain is also evident and appears to be conserved throughout the Lbc subfamily of RhoGEFs. Structural determinants of RhoA binding and nucleotide exchange in leukemia-associated Rho guanine-nucleotide exchange factor.,Kristelly R, Gao G, Tesmer JJ J Biol Chem. 2004 Nov 5;279(45):47352-62. Epub 2004 Aug 25. PMID:15331592[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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