NS2B/3 proteolysis at the C-prM junction of the tick-borne encephalitis virus polyprotein is highly membrane dependent

► An in vitro system to investigate NS2B/3 processing tick-borne encephalitis virus. ► Processing of protein C was dependent on the addition of microsomal membranes. ► Introduction of a HIV-1 cleavage site allowed cleavage HIV-1 protease. ► Insertion into membranes is disturbed by the presence of the HIV-1 cleavage site.