M2-1
Domain
Contains a zinc-finger domain on its N-terminus essential for its anti-termination function (PubMed:24434552). Contains an oligomerization domain (PubMed:22675274). The central globular core is responsible for binding to RNA and phosphoprotein (PubMed:22675274).
Function
Acts as a tetrameric transcription processivity factor that binds in a competitive manner to RNA and the phosphoprotein (P) to prevent premature termination during transcription (PubMed:19386701, PubMed:22675274). Transcription anti-terminator that enhances readthrough of intergenic junctions during viral transcription (PubMed:10364337, PubMed:27194388, PubMed:8552680, PubMed:9420254). Preferentially binds to poly(A)-rich sequences (PubMed:24434552). Plays a role in the association of the matrix protein with the nucleocapsid, which initiates assembly and budding (PubMed:18579594). Also, can activate host NF-kappa-B through association with host RELA (PubMed:15629770).
Post-translational modifications
Phosphorylated by host in infected cells (PubMed:10846068, PubMed:11711610, PubMed:29489893, PubMed:3339328). Only dephosphorylated M2-1 is competent for viral mRNA binding (PubMed:29489893). Cyclic turnover of phosphorylation-dephosphorylation of M2-1 is required for efficient viral transcription (PubMed:29489893).
Sequence Similarities
Belongs to the pneumoviridae M2-1 protein family.
Cellular localization
- Virion
- Host cytoplasm
- Host nucleus
- Localizes in cytoplasmic inclusion bodies substructures called inclusion bodies associated granules (IBAGs) (PubMed:22675274, PubMed:28916773, PubMed:29489893, PubMed:31649314). Forms a layer between the matrix and nucleocapsid (PubMed:23776214, PubMed:24760890).
Alternative names
Protein M2-1, Envelope-associated 22 kDa protein, Transcription antitermination factor M2-1, Vp24, M2-1