簡要描述： Retroviral envelope proteins mediate receptor recognition and membrane fusion during early infection. Endogenous envelope proteins may have kept, lost or modified their original function during evolution. This endogenous envelope protein has retained its original fusogenic properties and participates in trophoblast fusion during placenta morphogenesis.
SU mediates receptor recognition. This interaction triggers the refolding of the transmembrane protein (TM) and is thought to activate it