Related Experiment Video
Updated: May 9, 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
The guanine nucleotide exchange factor Rlf interacts with SH3 domain-containing proteins via a binding site with a
Milica Popovic1, Arjen J Jakobi2, Marije Rensen-de Leeuw1
1Department of Molecular Cancer Research, Centre of Biomedical Genetics and Cancer Genomics Centre, University Medical Center Utrecht, Utrecht, The Netherlands.
Abstract:
Rlf is a guanine nucleotide exchange factor for the small G-proteins RalA and RalB and couples Ras- to Ral-signalling. Here the crystal structure of the catalytic module of Rlf consisting of a REM- and a CDC25-homology domain is determined. The structure is distinguished by an extended three stranded β-sheet called the flagpole. The flagpole is a conserved element in the RalGDS family of guanine nucleotide exchange factors and stabilises the orientation of the REM-domain relative to the CDC25-homology domain. A proline-rich sequence in the flagpole is unique to Rlf and several proteins that interact with this sequence by SH3 domains are identified. Conformational pre-selection results in a gain of affinity and contributes to the establishment of SH3 domain selectivity.
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...
Rab Cascades
Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Directing Proteins to the Rough Endoplasmic Reticulum
GTPases and their Regulation
Large G-proteins, also known...

