Table 4:

Summary of the functions of the structural proteins of alphaviruses

Protein	Function
Capsid	Forms the virion structure, selects for packaging of viral RNA, involved in initiating budding from the cell, in the New-World viruses inhibits cellular translation and transcription^{127,128,140,191–194,198,228}
E1	Forms heterotrimers with E2 to form the glycoprotein spikes, fuses the viral and host cell membranes, forms pores in the endosome to induce pH changes^{63,68–70,210,229}
E2	Forms heterotrimers with E1 to from the glycoprotein spikes²⁰⁹
E3	Functions as the signal sequence for the structural polypeptide, protects E1 from acidic pH, additional functions involved in trafficking and virulence^213–215
6K	Involved in budding, may help space the glycoproteins on the virion, may function as a viroporin^216,218
TF	Involved in evading interferon due to specific palmitoylation, may be a viroporin, incorporated into the virion^216,224,225