Recently, two independent studies elegantly showed the requirement of the endosomal cholesterol transporter Niemann-Pick C1 (NPC1) for the entry of both MARV GP-pseudotyped viruses (VSV and MLV) as well as infectious MARV [94, 95] . It was also shown that NPC1 catalytic activity is not required for EBOV infection indicating that specific binding to NPC1 rather than its role in cholesterol transport is required, although this was not tested for MARV [95] . In one of the studies identifying NPC1 as the MARV entry receptor, it was also determined that members of the homotypic fusion and vacuole protein-sorting (HOPS) complex were important for EBOV entry, although they appeared to play a less important role in MARV entry [94] .