extracellular domain (ECD) found in lymphocyte antigen 6E (Ly-6E) and similar proteins
Ly-6E (also called retinoic acid-induced gene E protein (RIG-E), or stem cell antigen 2 (SCA-2), or thymic shared antigen 1 (TSA-1)) is a GPI-anchored cell surface protein that regulates T-lymphocytes proliferation, differentiation, and activation. It restricts the entry of human coronaviruses, including SARS-CoV, MERS-CoV and SARS-CoV-2, by interfering with spike protein-mediated membrane fusion. It plays an essential role in placenta formation by acting as the main receptor for syncytin-A (SynA). It may also act as a modulator of nicotinic acetylcholine receptors (nAChRs) activity. Ly-6E contains an extracellular domain (ECD) which belongs to Ly-6 antigen/uPA receptor-like (LU) superfamily and exhibits a snake toxin-like fold (also known as three-finger toxin/3FTx fold or three-fingered protein/TFP domain fold).
Jiyao W et al.(2023). "The conserved domain database in 2023.",