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Published on: June 3, 2012
Sumoylation of Human Parainfluenza Virus Type 3 Phosphoprotein Correlates with A Reduction in Viral Replication
Qi Cheng1, Wenjing Huai1, Xiaoyan Wu1
1State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
Abstract:
Human parainfluenza virus type 3 (HPIV3), a member of the Paramyxoviridae family, can cause lower respiratory disease in infants and young children. The phosphoprotein (P) of HPIV3 is an essential cofactor of the viral RNA-dependent RNA polymerase large protein (L). P connects nucleocapsid protein (N) with L to initiate genome transcription and replication. Sumoylation influences many important pathways of the target proteins, and many viral proteins are also themselves sumoylated. In this study, we found that the P of HPIV3 could be sumoylated, and mutation of K492 and K532 to arginine (PK492R/K532R) failed to be sumoylated within P, which enhances HPIV3 minigenome activity. Biochemical studies showed that PK492R/K532R had no effect on its interactions with N, formation of homo-tetramers and formation of inclusion bodies. Finally, we found that incorporation of K492R/K532R into a recombinant HPIV3 (rHPIV3-PK492R/K532R) increased viral production in culture cells, suggesting that sumoylation attenuates functions of P and down-regulates viral replication.
Insights
Sumoylation of human parainfluenza virus type 3 phosphoprotein (P) attenuates its function. Mutating sumoylation sites in P enhances viral replication, suggesting a new target for antiviral therapies.
Area of Science:
- Virology
- Molecular Biology
- Post-translational Modifications
Background:
- Human parainfluenza virus type 3 (HPIV3) causes respiratory illness in children.
- The HPIV3 phosphoprotein (P) is crucial for viral RNA transcription and replication.
- Sumoylation is a post-translational modification affecting protein function.
Purpose of the Study:
- To investigate the role of sumoylation in HPIV3 phosphoprotein (P) function.
- To determine the impact of sumoylation site mutations on viral activity.
Main Methods:
- Site-directed mutagenesis to create non-sumoylated P variants (PK492R/K532R).
- Minigenome assays to assess viral polymerase activity.
- Biochemical assays to evaluate protein interactions and complex formation.
- Generation of recombinant HPIV3 (rHPIV3-PK492R/K532R) for replication studies.
Main Results:
- HPIV3 P protein is sumoylated.
- Mutations at K492 and K532 abolished P sumoylation and enhanced minigenome activity.
- The PK492R/K532R mutant retained interactions with N, homo-tetramerization, and inclusion body formation.
- Recombinant HPIV3 with mutated P (rHPIV3-PK492R/K532R) showed increased viral production.
Conclusions:
- Sumoylation of HPIV3 P attenuates its function and down-regulates viral replication.
- Disrupting P sumoylation enhances viral production, indicating sumoylation as a negative regulator of HPIV3.
- Targeting P sumoylation may offer a novel antiviral strategy against HPIV3 infections.
