When MARV-infected cells were treated with various stimuli, including IFNα, IFNγ, and IL6, it was shown that the STAT proteins were neither phosphorylated nor translocated into the nucleus [126, 127] . It was then shown that in MARV-infected cells treated with exogenous stimuli, Janus kinases were also not phosphorylated and VP40 was identified as the viral protein inhibiting IFN signaling. It is believed that Jak1 is the target for VP40, however, the mechanism of VP40-induced inhibition is not completely understood [126] . Intriguingly, EBOV is also able to block IFN signaling by employing a completely different mechanism. EBOV VP24 blocks the nuclear translocation of phosphorylated STAT proteins by binding to STAT1 and importins involved in the nuclear transport of specific STAT proteins ( Figure 6 ) ( [128] , reviewed in [129] ).