Furin cleaves p62 after the tetrabasic motif “RHRR” late in the exocytic pathway to produce the mature E2/E1 heterodimer [39,41,126], but cleavage is not required for particle assembly/budding, and either furin cleavage site mutations that prevent processing or infection of furin-deficient cell lines still support particle production [39,51,52,53,127]. The gene discussed is FURIN; the disease is infection.