ERVW-1 Protein, Human (His-SUMO)

The endogenous retroviral envelope protein ERVW-1 has preserved its inherent fusogenic properties, playing a pivotal role in trophoblast fusion and the establishment of a syncytium during placental morphogenesis. Its capacity for inducing fusion is facilitated through the binding of SLC1A4 and SLC1A5. Endogenous envelope proteins, like ERVW-1, may exhibit varied evolutionary fates, maintaining, losing, or altering their original functions over time. Retroviral envelope proteins, comprising a surface protein (SU) for receptor recognition and a transmembrane protein (TM) acting as a class I viral fusion protein, are critical for receptor recognition and membrane fusion in early infection. ERVW-1 likely adopts three conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. In the context of viral and target cell membrane fusion, the coiled coil regions (heptad repeats) transition to a trimer-of-hairpins structure, bringing the fusion peptide close to the ectodomain's C-terminal region—a structural arrangement believed to drive membrane apposition and subsequent fusion.