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Smurf2 alters BPV1 trafficking and decreases infection
Sarah A Dabydeen1, Patricio I Meneses
1School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
Abstract:
Papillomavirus capsid proteins L1 and L2 mediate virion attachment, internalization and trafficking. In our studies of the capsid proteins, we identified an interaction of L2 with the E3 ligase Smad ubiquitin regulatory factor 2 (Smurf2). Smurf2 expression alters BPV1 virion trafficking and L2 protein levels. Using BPV1 pseudovirions (PSVs) containing a GFP or DSRed transgene encapsidated by L1 and L2 proteins, our data showed that although only BPV1 L2 interacts with Smurf2, both L1 and L2 levels decrease in a Smurf2- and ubiquitin-dependent manner. The decrease in L2 protein levels corresponded to a decrease in infection (i.e., loss of GFP or DSRed expression). We propose that Smurf2 regulates L2 protein cellular localization and therefore alters L2 protein levels. This change in trafficking and protein level decreases nuclear delivery and transcription of encapsidated pseudoviral transgenes and thus decreases BPV1 infection levels.
Insights
Bovine papillomavirus type 1 (BPV1) L2 protein interacts with Smad ubiquitin regulatory factor 2 (Smurf2), a protein that degrades L2. This interaction reduces BPV1 infection by altering virion trafficking and L2 protein levels.
Area of Science:
- Virology
- Molecular Biology
- Cellular Biology
Background:
- Papillomavirus capsid proteins L1 and L2 are crucial for viral entry and transport.
- The E3 ligase Smad ubiquitin regulatory factor 2 (Smurf2) is involved in protein degradation pathways.
Purpose of the Study:
- To investigate the interaction between BPV1 capsid proteins and Smurf2.
- To determine the effect of Smurf2 on BPV1 virion trafficking and protein levels.
- To elucidate the mechanism by which Smurf2 influences BPV1 infection.
Main Methods:
- Utilized BPV1 pseudovirions (PSVs) encapsidated by L1 and L2 proteins.
- Incorporated reporter genes (GFP or DSRed) within PSVs.
- Assessed protein levels and cellular localization through Smurf2 and ubiquitin-dependent assays.
Main Results:
- Identified a specific interaction between BPV1 L2 and Smurf2.
- Demonstrated that Smurf2 expression decreases both L1 and L2 protein levels in a ubiquitin-dependent manner.
- Observed a correlation between reduced L2 protein levels and decreased BPV1 infection.
Conclusions:
- Smurf2 regulates BPV1 L2 protein cellular localization and stability.
- Altered trafficking and reduced L2 protein levels by Smurf2 impair nuclear delivery and transcription of viral transgenes.
- Smurf2 negatively impacts BPV1 infection levels through modulation of L2 protein.
