GP1 is responsible for binding to the receptor(s) on target cells. Interacts with CD209/DC-SIGN and CLEC4M/DC-SIGNR which act as cofactors for virus entry into the host cell. Binding to CD209 and CLEC4M, which are respectively found on dendritic cells (DCs), and on endothelial cells of liver sinusoids and lymph node sinuses, facilitate infection of macrophages and endothelial cells. These interactions not only facilitate virus cell entry, but also allow capture of viral particles by DCs and subsequent transmission to susceptible cells without DCs infection (trans infection) (By similarity). GP2 acts as a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During viral and target cell membrane fusion, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induces an irreversible conformational change in GP2, releasing the fusion hydrophobic peptide (By similarity). Homotrimer; each monomer consists of a GP1 and a GP2 subunit linked by disulfide bonds. The resulting peplomers (GP1,2) protrude from the virus surface as spikes. GP1,2 interacts with human CD209 and CLEC4M (collectively referred to as DC-SIGN(R)). Asialoglycoprotein receptor (ASGP-R) may be a liver-specific receptor for GP1,2. Members of the Tyro3 receptor tyrosine kinase family may be cell entry factors interacting with GP1,2 (By similarity). In the cell, localizes to the plasma membrane lipid rafts, which probably represent the assembly and budding site. GP1 is not anchored to the viral envelope, but forms a disulfid-linked complex with the extravirion surface GP2. In the cell, both GP1 and GP2 localize to the plasma membrane lipid rafts, which probably represent the assembly and budding site. GP1 can also be shed after proteolytic processing. The coiled coil regions play a role in oligomerization and fusion activity. The transmembrane domain is essential and sufficient for recruitment envelope glycoproteins into VP40-enriched multivesicular bodies. N-glycosylated. O-glycosylated in the mucin-like region. Specific enzymatic cleavages in vivo yield mature proteins. The precursor is processed into GP1 and GP2 by host cell furin in the trans Golgi, and maybe by other host proteases, to yield the mature GP1 and GP2 proteins. The cleavage site corresponds to the furin optimal cleavage sequence [KR]-X-[KR]-R (By similarity). GP1 is phosphorylated on serine residues between residues 260 and 273. Filoviruses entry requires functional lipid rafts at the host cell surface. Essential for infectivity, as it is the sole viral protein expressed at the virion surface. Belongs to the filoviruses glycoprotein family.