2nty
From Proteopedia
Rop4-GDP-PRONE8
Structural highlights
FunctionRAC5_ARATH May be involved in cell polarity control during the actin-dependent tip growth of root hairs.[1] Inactive GDP-bound Rho GTPases reside in the cytosol, are found in a complex with Rho GDP-dissociation inhibitors (Rho GDIs), and are released from the GDI protein in order to translocate to membranes upon activation.[2] 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 of plants (Rop) proteins belong to the superfamily of small GTP-binding (G) proteins and are vital regulators of signal transduction in plants. In order to become activated, Rop proteins need to exchange GDP for GTP, an intrinsically slow process catalyzed by guanine nucleotide exchange factors (GEFs). RopGEFs show no homology to animal RhoGEFs, and the catalytic mechanism remains elusive. GEF-catalysed nucleotide exchange proceeds via transient ternary and stable binary complexes. While a number of structural studies have analyzed binary nucleotide-free G protein-GEF complexes, very little is known about the ternary complexes. Here we report the X-ray structure of the catalytic PRONE domain of RopGEF8 from Arabidopsis thaliana, both alone and in a ternary complex with Rop4 and GDP. The features of the latter complex, a transient intermediate of the exchange reaction never directly observed before, suggest a common mechanism of catalyzed nucleotide exchange applicable to small G proteins in general. Structural evidence for a common intermediate in small G protein-GEF reactions.,Thomas C, Fricke I, Scrima A, Berken A, Wittinghofer A Mol Cell. 2007 Jan 12;25(1):141-9. PMID:17218277[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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