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Mammarenavirus Z Protein Myristoylation and Oligomerization Are Not Required for Its Dose-Dependent Inhibitory Effect
Haydar Witwit1, Juan C de la Torre1
1Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Background/Objectives:
N-Myristoyltransferase inhibitors (NMTi) represent a novel antiviral strategy against mammarenaviruses such as Lassa and Junin viruses. The Z matrix protein inhibits viral ribonucleoprotein (vRNP) activity in a dose-dependent manner. Here, we investigated whether Z-mediated vRNP inhibition depends on Z myristoylation or oligomerization.
Methods:
We used HEK293T cells transfected with wild-type (WT) or G2A-mutated Z constructs in LCMV minigenome (MG) assays. Cells were treated with the NMTi IMP-1088 and the proteasome inhibitor MG132. Z protein expression, vRNP activity, and VLP production were analyzed by immunofluorescence, western blotting, and colocalization analyses.
Results:
IMP-1088 treatment led to proteasome-mediated degradation of Z, reducing its inhibition of vRNP activity, which was restored by MG132. The non-myristoylated Z G2A mutant retained vRNP inhibitory activity but showed impaired oligomerization and budding capacity. These findings demonstrate that Z-mediated vRNP inhibition is independent of myristoylation and oligomerization.
Conclusions:
Z myristoylation and oligomerization are not required for its inhibitory vRNP activity. Targeting Z myristoylation with NMTi impairs virus assembly and budding without affecting Z-mediated inhibition of vRNP activity, supporting the development of NMTi as a promising broad-spectrum antiviral strategy against mammarenaviruses.
Insights
N-Myristoyltransferase inhibitors (NMTi) do not require Z myristoylation or oligomerization for antiviral activity against mammarenaviruses. Targeting Z myristoylation with NMTi impairs virus assembly but not vRNP inhibition, supporting NMTi as a broad-spectrum antiviral strategy.
Area of Science:
- Virology
- Molecular Biology
- Drug Discovery
Background:
- N-Myristoyltransferase inhibitors (NMTi) offer a novel antiviral approach against mammarenaviruses like Lassa and Junin viruses.
- The viral Z matrix protein is known to inhibit viral ribonucleoprotein (vRNP) activity.
- The precise mechanisms underlying Z protein's vRNP inhibition, specifically the roles of myristoylation and oligomerization, were unclear.
Purpose of the Study:
- To investigate whether the Z protein's inhibition of vRNP activity is dependent on its myristoylation or oligomerization.
- To evaluate the impact of NMTi on Z protein function and viral processes.
Main Methods:
- Utilized HEK293T cells with wild-type (WT) and G2A-mutated Z constructs in LCMV minigenome assays.
- Administered NMTi IMP-1088 and proteasome inhibitor MG132 to assess Z protein degradation and vRNP activity.
- Analyzed Z protein expression, vRNP inhibition, and viral particle (VLP) production via immunofluorescence, western blotting, and colocalization.
Main Results:
- IMP-1088 treatment induced proteasome-dependent degradation of Z, reducing vRNP inhibition, which was reversible with MG132.
- The non-myristoylated Z G2A mutant maintained vRNP inhibitory capacity.
- The Z G2A mutant exhibited reduced oligomerization and impaired viral budding.
Conclusions:
- Z protein's inhibition of vRNP activity is independent of myristoylation and oligomerization.
- NMTi targeting Z myristoylation disrupts virus assembly and budding without compromising vRNP inhibition.
- NMTi represent a promising broad-spectrum antiviral strategy for mammarenaviruses.
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