BST-2/Tetherin Proteins and Enzymes

BST2, also known as CD317, Tetherin, and PDCA1, is a 30-35 kDa interferon-inducible protein that associates with the plasma membrane with its transmembrane segment and GPI anchor. BST2 is expressed on bone marrow stromal cells and is upregulated in breast cancer and astrocytoma. It binds to ILT7 on plasmacytoid dendritic cells and inhibits proinflammatory TLR7 and TLR9 signaling. BST2 inhibits the release of Kaposi sarcoma virus, HIV-1, and Lassa virus from infected cells, but this function is counteracted by viral proteins which directly bind and trigger the degradation of BST2.