Rotavirus Outer Capsid Protein VP4 (VP4)

Rotavirus Outer Capsid Protein VP4, commonly referred to as the P antigen, is a vital structural protein that forms the spikes on the surface of the rotavirus virion (UniProt: P04502). It plays a fundamental role in the viral life cycle by mediating attachment to host cell receptors, such as sialic acids or histo-blood group antigens, and facilitating the penetration of the host cell membrane (PubMed: 22837215). For the virus to become infectious, VP4 must be proteolytically cleaved by trypsin-like enzymes into two subunits: VP8*, which handles receptor binding, and VP5*, which mediates membrane fusion (NCBI: NBK7646). Because it is a primary target for neutralizing antibodies, VP4 is a central component in the development of live-attenuated and recombinant rotavirus vaccines like Rotarix and RotaTeq (CDC: Rotavirus Vaccination). The diversity of VP4, classified into various P-genotypes, is a major factor in the epidemiology of rotavirus and influences the breadth of vaccine-induced immunity (PubMed: 16439531). Understanding the structural variations in VP4 is vital for monitoring vaccine efficacy against different circulating strains and for the development of next-generation therapeutics (PubMed: 25135945).

Other names

P antigenProtease-cleaved proteinVP4 spike proteinViral protein 4Outer capsid protein VP4

Neutralization of viral infectivity by blocking attachment to host cell receptors and preventing membrane penetration.