Initial binding to target cell probably involves interaction of E(rns) with glycosaminoglycans. E1 and/or E2 are responsible of cell attachment with CD46 and subsequent fusion after internalization of the virion by endocytosis (Probable).

P7 forms a leader sequence to properly orient NS2 in the membrane. 
Uncleaved NS2-3 is required for production of infectious virus.

NS2 protease seems to play a vital role in viral RNA replication control and in the pathogenicity of the virus.

NS3 displays three enzymatic activities: serine protease, NTPase and RNA helicase.

NS4A is a cofactor for the NS3 protease activity.

RNA-directed RNA polymerase NS5 replicates the viral (+) and (-) genome.