Related Experiment Video
Updated: Jan 10, 2026
08:55
Characterization of Multi-subunit Protein Complexes of Human MxA Using Non-denaturing Polyacrylamide Gel-electrophoresis
Published on: October 28, 2016
10.8K
A monomeric GTPase-negative MxA mutant with antiviral activity
1Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universität Freiburg, D-79008 Freiburg, Germany.
Journal of Virology
|August 10, 2000
Summary
MxA monomers, even without GTPase activity, inhibit RNA viruses like Thogoto virus. This suggests GTP hydrolysis isn't essential for MxA's antiviral function, challenging previous assumptions.
Area of Science:
- Virology
- Molecular Biology
- Immunology
Background:
- MxA is an interferon-induced GTPase known for antiviral properties against RNA viruses.
- MxA forms large oligomers, but the roles of oligomerization and GTPase activity in its antiviral function remain unclear.
Purpose of the Study:
- To investigate the necessity of MxA oligomerization and GTPase activity for its antiviral function.
- To determine if monomeric MxA retains antiviral capabilities.
Main Methods:
- Utilized a mutant MxA protein (MxA(L612K)) that cannot form oligomers and lacks GTPase activity.
- Assessed antiviral activity in transiently transfected Vero cells and a Thogoto virus minireplicon system.
- Monitored MxA protein stability and degradation rates.
Main Results:
- Monomeric MxA(L612K) demonstrated significant inhibition of Thogoto virus and vesicular stomatitis virus.
- MxA(L612K) lacks detectable GTPase activity, indicating antiviral function can occur without it.
- MxA(L612K) is rapidly degraded, contrasting with the stability of wild-type MxA.
Conclusions:
- MxA monomers possess intrinsic antiviral activity, independent of oligomerization and GTPase function.
- GTP hydrolysis may not be a prerequisite for MxA's antiviral mechanism.
- High-molecular-weight MxA oligomers might serve as a stable reservoir for active MxA monomers.
