Furin-mediated protein processing in infectious diseases and cancer

Braun, Elisabeth; Sauter, Daniel

In contrast to flavivirus prM, which can be cleaved during egress and entry, papillomavirus L2 seems to be exclusively cleaved on target cells. 80 A model has been proposed, in which attachment of papillomaviruses to heparan sulphate proteoglycans induces a conformational change in L2 that exposes the polybasic cleavage site. 81 Upon proteolytic processing of L2, L1 may engage a secondary cellular receptor and mediate infection 80 (Figure 3b, right panel) . Furthermore, interaction of cleaved L2 with an unknown intracellular receptor may be required for escape of L2 from the endosomal compartment and its ability to escort viral DNA into the nucleus. 80 This illustrates that also nonenveloped viruses have evolved the ability to exploit furin or related PCSKs for their own purposes.