Endogenous retrovirus group 3 member 1 Env polyprotein

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 lost its fusogenic properties. It can inhibit cell growth through decrease expression of cyclin B1 and increased expression of p21 in vitro.; SU mediates receptor recognition.; TM anchors the envelope heterodimer to the viral membrane through one transmembrane domain. The other hydrophobic domain, called fusion peptide, mediates fusion of the viral membrane with the target cell membrane (By similarity).