Cryo-EM structure of the sub-50 kD PDZ-RhoGEF catalytic core-RhoA complex reveals an allosteric mechanism for GEF switch
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 angstrom 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.
Related
- Catalytic mechanism and allosteric regulation of an oligomeric (p)ppGpp synthetase by an alarmone.
- Mechanism of catalytic regulation by an allosteric hot spot in dihydrofolate reductase
- A Binding Site for CVN293 Reveals a Mechanism for Allosteric Control of THIK-1 K2P Channel Gating
- Mechanism of the Sequential Trajectory of Allosteric Ring Closure in Human Chaperonin TRiC
- Fragment-based drug discovery strategy reveals an unprecedented allosteric binding site in Mycobacterium tuberculosis DNA gyrase
BibTeX
@misc{braga2026cryoem,
title = {{Cryo-EM structure of the sub-50 kD PDZ-RhoGEF catalytic core-RhoA complex reveals an allosteric mechanism for GEF switch}},
author = {Matthew Villanueva Braga and Emma Barpal and Sheng Li and Jennifer N. Cash},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.21.760610},
url = {https://www.biorxiv.org/content/10.64898/2026.10.21.760610v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Cryo-EM structure of the sub-50 kD PDZ-RhoGEF catalytic core-RhoA complex reveals an allosteric mechanism for GEF switch
AU - Matthew Villanueva Braga
AU - Emma Barpal
AU - Sheng Li
AU - Jennifer N. Cash
PY - 2026
DA - 2026/10/21
PB - bioRxiv
DO - 10.64898/2026.10.21.760610
UR - https://www.biorxiv.org/content/10.64898/2026.10.21.760610v1
AB - 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 angstrom 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.
SN - 2692-8205
ER -