Interestingly, arenaviruses do not have an obvious counterpart of M. However, Z has been shown to be the main driving force of arenavirus budding Strecker et al., 2003; Urata et al., 2006) , a process mediated by the Z late (L) domain motifs: PTAP and PPPY similar to those known to control budding of several other viruses including HIV and Ebola virus, via interaction with specific host cell proteins (Freed, 2002) .