Cellular stress increases DRIP production and MHC Class I antigen presentation.

Area of Science:

• Immunology
• Virology
• Molecular Biology

Background:

• Defective ribosomal products (DRiPs) are rapidly degraded proteins crucial for MHC class I ligand generation.
• While many cellular DRiPs are known, viral DRiPs at the protein level remained undescribed.
• This study aimed to characterize and identify DRiPs originating from a viral protein.

Purpose of the Study:

• To identify and characterize defective ribosomal products (DRiPs) derived from a viral protein.
• To investigate the role of protein modification and cellular stress in DRiP formation and antigen presentation.
• To explore the implications for vaccination strategies.

Main Methods:

• Utilized lymphocytic choriomeningitis virus (LCMV) nucleoprotein (NP) conjugated with ubiquitin or ubiquitin-like modifiers (FAT10, ISG15).
• Monitored DRiP formation and degradation using western blot with a FLAG tag.
• Assessed antigen presentation via flow cytometry and cytotoxic T cells.

Main Results:

• Identified short-lived DRiPs derived from LCMV-NP, specifically when modified with ubiquitin or ubiquitin-like modifiers.
• Demonstrated proteasome-dependent degradation of these viral DRiPs.
• Showed enhanced DRiP synthesis and NP118-126 presentation under cellular stress (FCS starvation) and protein modification.

Conclusions:

• Visualized viral DRiPs for the first time, originating from LCMV-NP.
• DRiP formation and subsequent MHC class I presentation are enhanced by cellular stress and protein modification.
• Findings suggest new avenues for developing vaccination strategies targeting viral DRiPs.