Outer capsid protein VP4 (Rotavirus spike protein) (VP4)

Rotavirus VP4 is a spike-forming outer capsid protein that serves as the primary attachment and entry factor for rotavirus infection of host epithelial cells. The protein projects approximately 20 nm from the virion surface as 60 trimeric spikes and contains integrin ligand recognition sequences that facilitate binding to host cell integrins, particularly α2β1[1][2][6]. VP4 undergoes trypsin-mediated cleavage into two functional fragments—VP8* (N-terminal receptor-binding domain) and VP5* (C-terminal membrane penetration domain)—which is essential for efficient viral infectivity and cell entry[2][6]. The protein interacts with cellular endosomal machinery through binding partners Rab5a and PRA1, facilitating internalization via receptor-mediated endocytosis[5]. As a major determinant of host cell tropism and a target for neutralizing antibodies, VP4 represents a critical viral entry component and potential therapeutic target for rotavirus-related gastroenteritis[1][3].

Other names

Spike protein VP4Rotavirus attachment proteinP-type neutralization antigen

Integrin ligand interaction: VP4 contains the DGE tripeptide sequence that acts as an α2β1 integrin recognition site Receptor-mediated endocytosis through interaction with cellular proteins Rab5 and PRA1 Trypsin cleavage activation: VP4 undergoes proteolytic cleavage into VP8* (receptor-binding fragment) and VP5* (membrane penetration fragment), which increases virus infectivity Cell surface receptor binding followed by endocytic internalization