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 (By similarity). Interacts with NP (PubMed:28566377, PubMed:28659479). Disrupts innate immune signaling in infected host cell (By similarity). Belongs to the filoviridae polymerase cofactor VP35 family.