Cryo-EM structures of autoinhibited and RNA-activated ZNFX1 helicase
4 affiliations
- 1Department of Structural Biology, Van Andel Institute, Grand Rapids, MI USA
- 2University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD USA
- 3Division of Translational Radiation Sciences, Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD USA
- 4Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University School of Medicine, Baltimore, MD USA
Abstract
ZNFX1 is an RNA helicase that plays a critical role in host defense against viral infections. Recent studies further revealed that ZNFX1 harbors an unexpected RNA-ubiquitinating E3 ligase activity, raising fundamental questions about how RNA-binding activates this multifunctional enzyme. Here, we combine cryo-electron microscopy with biochemical analyses to define the structural basis of ZNFX1 regulation. In the absence of RNA, ZNFX1 adopts an autoinhibited conformation in which a blocking helix occludes the RNA-binding groove. It exists predominantly as autoinhibited monomers, and, at higher concentrations, assembles into short helical filaments composed of repeating tetramers. Binding of single-stranded RNA (ssRNA) remodels these higher-order assemblies into RNA-bound ZNFX1 monomers and dimers. The cryo-EM structure of the ssRNA-bound ZNFX1 dimer reveals that RNA binding displaces the blocking helix and induces large-scale conformational rearrangements that remodel the helicase core into an active configuration. Biochemical analyses validate the proposed RNA-binding interfaces and demonstrate ATP-dependent RNA unwinding by ZNFX1. Together, these findings support a regulatory mechanism in which autoinhibited ZNFX1 exists as monomers or concentration-dependent higher-order oligomers, whereas RNA binding promotes structural remodeling and helicase activation.
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BibTeX
@article{he2026cryoem,
title = {{Cryo-EM structures of autoinhibited and RNA-activated ZNFX1 helicase}},
author = {Qing He and Feng Wang and Feyruz V. Rassool and Stephen B. Baylin and Huilin Li},
journal = {Nature Communications},
year = {2026},
month = sep,
doi = {10.1038/s41467-026-78145-0},
url = {https://doi.org/10.1038/s41467-026-78145-0},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Cryo-EM structures of autoinhibited and RNA-activated ZNFX1 helicase
AU - Qing He
AU - Feng Wang
AU - Feyruz V. Rassool
AU - Stephen B. Baylin
AU - Huilin Li
PY - 2026
DA - 2026/09/25
JO - Nature Communications
DO - 10.1038/s41467-026-78145-0
UR - https://doi.org/10.1038/s41467-026-78145-0
AB - ZNFX1 is an RNA helicase that plays a critical role in host defense against viral infections. Recent studies further revealed that ZNFX1 harbors an unexpected RNA-ubiquitinating E3 ligase activity, raising fundamental questions about how RNA-binding activates this multifunctional enzyme. Here, we combine cryo-electron microscopy with biochemical analyses to define the structural basis of ZNFX1 regulation. In the absence of RNA, ZNFX1 adopts an autoinhibited conformation in which a blocking helix occludes the RNA-binding groove. It exists predominantly as autoinhibited monomers, and, at higher concentrations, assembles into short helical filaments composed of repeating tetramers. Binding of single-stranded RNA (ssRNA) remodels these higher-order assemblies into RNA-bound ZNFX1 monomers and dimers. The cryo-EM structure of the ssRNA-bound ZNFX1 dimer reveals that RNA binding displaces the blocking helix and induces large-scale conformational rearrangements that remodel the helicase core into an active configuration. Biochemical analyses validate the proposed RNA-binding interfaces and demonstrate ATP-dependent RNA unwinding by ZNFX1. Together, these findings support a regulatory mechanism in which autoinhibited ZNFX1 exists as monomers or concentration-dependent higher-order oligomers, whereas RNA binding promotes structural remodeling and helicase activation.
SN - 2041-1723
ER -