Related Experiment Video
Updated: Jun 17, 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
RabGDI displacement by DrrA from Legionella is a consequence of its guanine nucleotide exchange activity
Stefan Schoebel1, Lena Katharina Oesterlin, Wulf Blankenfeldt
1Department of Physical Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, NRW, Germany.
Abstract:
Prenylated 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.
Related Concept Videos
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...
Small GTPases - Ras and Rho
Three regulatory proteins control their activity:
Rab Cascades
Leaky Scanning
GPCRs Regulate Adenylyl Cylase Activity
Two...
The Ras Gene
Ras is a superfamily...

