Evolution-guided prioritization identifies a tissue-specific phosphorylation switch on herpes simplex virus 1 UL7...

Area of Science:

• Virology
• Molecular Biology
• Bioinformatics

Background:

• Phosphorylation sites on herpes simplex virus 1 (HSV-1) proteins are numerous but their functional significance is often unclear.
• Existing phosphoproteomic data lacks a method for prioritizing functionally relevant sites.
• Viruses utilize phosphorylation for intricate regulation of replication and pathogenicity.

Purpose of the Study:

• To develop and apply an evolution-guided strategy for prioritizing functionally relevant phosphorylation sites on HSV-1 proteins.
• To investigate the role of conserved phosphorylation sites, specifically UL6 Tyr-234 and UL7 Tyr-89, in HSV-1 replication and pathogenicity.

Main Methods:

• Integrated phosphoproteomic data with residue-level conservation across the Simplexvirus genus.
• Prioritized phosphorylation sites based on evolutionary conservation.
• Utilized phosphomimetic and non-phosphorylatable mutations for functional analysis of UL6 Tyr-234 and UL7 Tyr-89.

Main Results:

• Identified 46 highly conserved phosphorylation sites (≥88% conservation).
• Phosphomimetic mutations at UL6 Tyr-234 and UL7 Tyr-89 significantly reduced HSV-1 yields in cell culture.
• Phosphorylation at UL7 Tyr-89 demonstrated tissue-specific regulation, impacting HSV-1 replication and CNS pathogenicity in mice.

Conclusions:

• The evolution-guided strategy effectively prioritizes functionally relevant phosphorylation sites.
• Phosphorylation at UL7 Tyr-89 acts as a context-dependent inhibitory switch, modulating HSV-1 activity.
• UL7 Tyr-89 phosphorylation plays a crucial role in fine-tuning HSV-1 replication and pathogenicity, particularly within the central nervous system.