Spike glycoprotein E2: Plays a role in viral attachment to target host cell, by binding to the cell receptor. Synthesized as a p62 precursor which is processed by furin at the cell membrane just before virion budding, giving rise to E2-E1 heterodimer. The p62-E1 heterodimer is stable, whereas E2-E1 is unstable and dissociate at low pH. p62 is processed at the last step, presumably to avoid E1 fusion activation before its final export to cell surface. E2 C-terminus contains a transitory transmembrane that would be disrupted by palmitoylation, resulting in reorientation of the C-terminal tail from lumenal to cytoplasmic side. This step is critical since E2 C-terminus is involved in budding by interacting with capsid proteins. This release of E2 C-terminus in cytoplasm occurs lately in protein export, and precludes premature assembly of particles at the endoplasmic reticulum membrane. Spike glycoprotein E2: Processing of the precursor of protein E3/E2 into E2 and E3 results in a heterodimer of the spike glycoproteins E2 and E1. Spike glycoprotein E2: Spike at virion surface are constituted of three E2-E1 heterodimers. Spike glycoprotein E2: Interacts with 6K protein. Structural polyprotein: As soon as the capsid protein has been autocleaved, an internal uncleaved signal peptide directs the remaining polyprotein to the endoplasmic reticulum. Structural polyprotein: Specific enzymatic cleavages in vivo yield mature proteins. Capsid protein is auto-cleaved during polyprotein translation, unmasking a signal peptide at the N-terminus of the precursor of E3/E2. The remaining polyprotein is then targeted to the host endoplasmic reticulum, where host signal peptidase cleaves it into pE2, 6K and E1 proteins. pE2 is further processed to mature E3 and E2 by host furin in trans-Golgi vesicle. Spike glycoprotein E2: Palmitoylated via thioester bonds. These palmitoylations may induce disruption of the C-terminus transmembrane. This would result in the reorientation of E2 C-terminus from lumenal to cytoplasmic side. Spike glycoprotein E2: N-glycosylated. Structural polyprotein: Translated from a subgenomic RNA synthesized during togavirus replication.