RNA polymerase basic protein 2 subunit (PB2)

The **RNA polymerase basic protein 2 subunit (PB2)** is one of the three subunits (PA, PB1, PB2) comprising the influenza virus RNA-dependent RNA polymerase complex[5][8]. PB2 is essential for transcription and replication of the viral RNA genome, functioning primarily as a **cap-binding protein** that recognizes and binds the 5′ cap of host pre-mRNAs. This cap-snatching mechanism allows the viral polymerase to cleave the capped ends from host RNAs, using them as primers for viral mRNA synthesis[3][5]. PB2 also plays important roles in determining host specificity and pathogenesis—certain residues, especially Lys627, affect the virus’s ability to infect different species and influence virulence[1][10]. PB2 can interact with host proteins such as importin α (for nuclear import) and the mitochondrial antiviral signaling protein MAVS (modulating immune response)[2]. Because of its essential enzymatic function and unique structural features, PB2 is a validated therapeutic target for the development of anti-influenza drugs, especially those that block its cap-binding domain and thereby inhibit viral mRNA transcription[3][4]. Key resistance-conferring mutations and adaptation markers are well studied in the PB2 sequence.

Other names

PB2Polymerase basic protein 2Influenza virus PB2

Inhibition of cap-binding domain to prevent cap-snatching and viral mRNA synthesis; Inhibition of RNA-dependent RNA polymerase activity; Disruption of PB2-host interactions (e.g., with importin α or MAVS)