Chikungunya virus envelope glycoprotein E2 (E2)

Chikungunya virus envelope glycoprotein E2 is a viral structural protein crucial for mediating attachment of the virus to host cell receptors, thus enabling viral entry. E2 forms part of the viral surface as heterodimers with E1, organizing into 80 spikes per virion. After furin cleavage of the p62 precursor (pE2), mature E2 is exposed on the viral envelope and acts as the primary antigenic determinant recognized by the host immune system. E2 has three domains (A, B, and C): domains A and B mediate cell attachment, with domain B binding glycosaminoglycans (GAGs, including heparan sulfate) and domain A allowing for GAG-independent entry routes. E2 interacts with host molecules such as Mxra8 and heparan sulfate during infection. The protein’s conformational flexibility is important for viral fusion, with mutations in E2 affecting tropism, virulence, and immune evasion. E2 is a major target for neutralizing antibodies and vaccine development, and anti-E2 antibody responses are used for serological diagnosis of Chikungunya virus infection. No direct small-molecule drugs are currently licensed against E2; only experimental approaches and vaccine candidates exist.

Other names

E2 proteinEnvelope glycoprotein E2CHIKV E2pE2 (precursor form)E2 structural protein

Neutralizing antibodies: Block E2-receptor or E2-cell binding, preventing viral entry. Small molecules (experimental): Could disrupt E2 folding or its interaction with host cell receptors.