Syncytin-1 Antibody Blocking P

The mature envelope protein (Env) consists of a trimer of SU-TM heterodimers attached probably by a labile interchain disulfide bond. Interacts with the C-type lectin CD209/DC-SIGN.

Expressed at higher level in placental syncytiotrophoblast. Expressed at intermediate level in testis. Seems also to be found at low level in adrenal tissue, bone marrow, breast, colon, kidney, ovary, prostate, skin, spleen, thymus, thyroid, brain and trachea. Both mRNA and protein levels are significantly increased in the brain of individuals with multiple sclerosis, particularly in astrocytes and microglia.

This endogenous retroviral envelope protein has retained its original fusogenic properties and participates in trophoblast fusion and the formation of a syncytium during placenta morphogenesis. May induce fusion through binding of SLC1A4 and SLC1A5 (PubMed:10708449, PubMed:12050356, PubMed:23492904).3 Publications

Endogenous envelope proteins may have kept, lost or modified their original function during evolution. Retroviral envelope proteins mediate receptor recognition and membrane fusion during early infection. The surface protein (SU) mediates receptor recognition, while the transmembrane protein (TM) acts as a class I viral fusion protein. The protein may have 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 membranes.

Many different human endogenous retrovirus (HERV) families are expressed in normal placental tissue at high levels, suggesting that HERVs are functionally important in reproduction. This gene is part of an HERV provirus on chromosome 7 that has inactivating mutations in the gag and pol genes. This gene is the envelope glycoprotein gene which appears to have been selectively preserved. The gene's protein product is expressed in the placental syncytiotrophoblast and is involved in fusion of the cytotrophoblast cells to form the syncytial layer of the placenta. The protein has the characteristics of a typical retroviral envelope protein, including a furin cleavage site that separates the surface (SU) and transmembrane (TM) proteins which form a heterodimer. Alternatively spliced transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Mar 2010]