Cryo-EM structure of the sub-50 kD PDZ-RhoGEF catalytic core–RhoA complex reveals an allosteric mechanism for GEF switch
Year: 2026
Type: preprint
Abstract: PDZ-RhoGEF (PRG) drives cellular processes including migration through activation of the GTPase RhoA. The GEF switch (GS) is an accessory region N-terminal to the PRG catalytic core that significantly enhances its activity against RhoA, but its mechanism is unknown. We take an integrative structural biology approach, including cryogenic electron microscopy, to deduce the GS mechanism. Enzymatic assays define interactions between the GS and PRG catalytic core that are required for enhancement of activity. While SEC-SAXS data suggest that the GS does not alter the global structure of the catalytic core-RhoA complex, HDX-MS data reveal that the GS induces widespread stabilization, particularly in the RhoA switch regions. We determined a sub-4 Å resolution structure of 46 kD of the complex between the catalytic core and RhoA, revealing that Switch I is more flexible without the GS. Collectively, these data suggest both direct and allosteric factors in the mechanism of the GS.
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
Funders: U.S. Department of Energy, National Institutes of Health, University of California, Davis, University of California, San Francisco, National Cancer Institute, National Institute of General Medical Sciences, National Institute of Allergy and Infectious Diseases, Basic Energy Sciences, Biological and Environmental Research, Comprehensive Cancer Center, University of California, Davis, Lawrence Berkeley National Laboratory
Awards: Training Program in Molecular and Cellular Biology, G2075359013, G2603595557, G2806913346, G334911014, G3748365201, G786093667, G7938659809, G8229677252, G8760597890, ALS Efficiently Networking Advanced Beam Line Experiments (ALS-ENABLE), Cancer Center Support Grant P30, ChimeraX -- Next Generation Visualization and Analysis Software for Multiscale Modeling, Structural and Functional Characterization of RhoGEF Regulation Using Nanodiscs to Assemble Membrane-associated Signaling Scaffolds
OpenAlex ID: W7223096706