Modular organization of rabies virus phosphoprotein

Area of Science:

• Virology
• Structural Biology
• Molecular Biology

Background:

• Phosphoproteins (P) are essential components of Mononegavirales viruses, playing critical roles in viral replication.
• While P proteins fulfill similar functions across different viruses, they exhibit variations in length and oligomerization.
• Paramyxoviridae P proteins possess a modular organization of structured domains and intrinsically disordered regions.

Purpose of the Study:

• To predict the domain organization of phosphoproteins from Sendai virus, vesicular stomatitis virus (VSV), and rabies virus (RV).
• To validate the predicted modular structure of the rabies virus P protein and characterize the functional properties of its domains.
• To investigate the conserved organization of P proteins within the Rhabdoviridae family.

Main Methods:

• Utilized predictions of secondary structure disorder and sequence conservation analysis to predict P protein domain organization.
• Developed a novel procedure to integrate results from multiple prediction methods for boundary determination.
• Employed yeast two-hybrid assays and biochemical approaches to characterize RV P protein fragments.

Main Results:

• Predicted a modular organization for P proteins in Sendai virus, VSV, and RV, with structured domains alternating with disordered regions.
• Confirmed that central and C-terminal domains of RV P protein can fold independently.
• Identified the central domain as the oligomerization domain and the C-terminal domain as the nucleocapsid-binding domain.

Conclusions:

• The P proteins of Rhabdoviridae exhibit a conserved modular organization, similar to that observed in Paramyxoviridae.
• The identified domains (oligomerization and nucleocapsid-binding) are functionally autonomous.
• This conserved domain arrangement likely contributes to the functional similarities of P proteins across Mononegavirales.