Related Experiment Video
Updated: May 16, 2026

Affinity Precipitation of Active Rho-GEFs Using a GST-tagged Mutant Rho Protein (GST-RhoA(G17A)) from Epithelial Cell Lysates
Published on: March 31, 2012
Structure of the Rho-specific guanine nucleotide-exchange factor Xpln
Kazutaka Murayama1, Miyuki Kato-Murayama, Ryogo Akasaka
1Graduate School of Biomedical Engineering, Tohoku University, 2-1 Seiryo, Aoba, Sendai 980-8575, Japan.
Abstract:
Xpln is a guanine nucleotide-exchange factor (GEF) for Rho GTPases. A Dbl homology (DH) domain followed by a pleckstrin homology (PH) domain is a widely adopted GEF-domain architecture. The Xpln structure solely comprises these two domains. Xpln activates RhoA and RhoB, but not RhoC, although their GTPase sequences are highly conserved. The molecular mechanism of the selectivity of Xpln for Rho GTPases is still unclear. In this study, the crystal structure of the tandemly arranged DH-PH domains of mouse Xpln, with a single molecule in the asymmetric unit, was determined at 1.79 Å resolution by the multiwavelength anomalous dispersion method. The DH-PH domains of Xpln share high structural similarity with those from neuroepithelial cell-transforming gene 1 protein, PDZ-RhoGEF, leukaemia-associated RhoGEF and intersectins 1 and 2. The crystal structure indicated that the α4-α5 loop in the DH domain is flexible and that the DH and PH domains interact with each other intramolecularly, thus suggesting that PH-domain rearrangement occurs upon RhoA binding.
More Related Videos
Related Concept Videos
Small GTPases - Ras and Rho
Three regulatory proteins control their activity:
Rab Proteins
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Nuclear Export
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
Exon Recombination
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Directionality of Nuclear Transport
Rab Cascades

