– Butyrophilin subfamily 3 member A2, also known as BT3.2, BTF3, BTF4 and BTN3A2, is a single-pass type I membrane protein. It is a member of the butyrophilin (BTN) family and the immunoglobulin (IG) superfamily. Mature human BTN3A2 is a 305 amino acid (aa) glycoprotein. It contains a 219 aa extracellular region with one V-type Ig-like domain, and a 65 aa cytoplasmic tail. The cytoplasmic region undergoes phosphorylation on two serines. There are three potential splice forms. BTN3A2 is postulated to be expressed on immune-related cells, as it has a structural similarity to MHC and CD80/CD86 molecules. It plays a role in T-cell responses in the adaptive immune response and inhibits the release of IFNG from activated T-cells.