Key Points
- To determine the molecular mechanism and specific sequences responsible for membrane retention and virion attachment in the pestivirus glycoprotein E(rns).
- Quantified steady-state intracellular and secreted protein distributions using transient-expression cDNA constructs.
- Engineered green fluorescent protein (GFP) fusion constructs and truncation mutants targeting the E(rns) carboxy-terminal sequence to assess subcellular localization.
- Evaluated the strength of membrane association through differential biochemical extraction procedures.
- Transient expression demonstrated that 84% of E(rns) remains intracellularly membrane-associated under steady-state conditions, while 16% is secreted into the cell supernatant.
- Fusing the carboxy-terminal domain of E(rns) redirected cytosolic GFP to membranes, identifying an essential 11-amino-acid core that requires upstream or downstream accessory sequences to anchor.
- Extraction assays revealed an atypical intermediate attachment mechanism, binding more securely than peripheral membrane proteins but less tightly than standard transmembrane proteins.
Structured PICO
PPopulationTransfected cells expressing cDNA constructs of pestivirus E(rns) protein and GFP fusions
IInterventionTransient expression of E(rns) and GFP fusion constructs
CComparatorCytosolic GFP (for fusion experiments)
OOutcomeSubcellular localization and membrane binding properties of the E(rns) proteinsurrogate
The pestivirus E(rns) glycoprotein utilizes an unusual carboxy-terminal sequence for membrane anchoring, distinct from typical transmembrane or peripheral proteins.