Plays an essential role in viral RNA synthesis and also a role in suppressing innate immune signaling. Homooligomer. Homomultimerization via the coiled coil domain is a prerequisite for binding to L. Found in a trimeric complex in which VP35 bridges L and the nucleoprotein (PubMed:16282487). Interacts with NP (By similarity). Disrupts innate immune signaling in infected host cell (PubMed:30044983, PubMed:23028316). Belongs to the filoviridae polymerase cofactor VP35 family.