Poliovirus types 1, 2, and 3 capsid proteins (PV capsid proteins)

The poliovirus capsid is composed of 60 copies each of four structural proteins: VP1, VP2, VP3, and VP4, which together form an icosahedral shell surrounding the positive-sense RNA genome (UniProt: P03300). These proteins are derived from the cleavage of the P1 precursor polyprotein and are essential for the virus's life cycle, including host cell recognition via the CD155 receptor and the subsequent delivery of the viral genome into the cytoplasm (Wikipedia: Poliovirus). There are three distinct serotypes of poliovirus (PV1, PV2, and PV3), defined by the antigenic properties of these capsid proteins (CDC: Pink Book). Therapeutic strategies targeting the capsid include vaccines that elicit protective immune responses and small-molecule inhibitors, such as pocapavir, which bind to a hydrophobic pocket in VP1 to prevent the conformational changes required for viral uncoating (PubMed: PMID 24935976). Understanding the structural biology of these proteins is fundamental to the global polio eradication initiative and the management of potential outbreaks.

Other names

VP1VP2VP3VP4P1 polyproteinPoliovirus structural proteinsViral protein 1Viral protein 2Viral protein 3Viral protein 4

Capsid-binding antivirals like pocapavir bind to a hydrophobic pocket in the VP1 protein, stabilizing the capsid and preventing the uncoating and release of viral RNA into the host cell (PubMed: PMID 1730710). Vaccines (IPV and OPV) work by inducing neutralizing antibodies that bind to the capsid surface, sterically hindering the virus from attaching to the host receptor CD155 (StatPearls: Poliomyelitis).