Interaction of BST-2 with HIV-1 proteins. Vpu interacts with BST-2 through its transmembrane domain. Interaction of BST-2 with Nef involves the cytoplasmic domain. The interaction of HIV-2 Env with BST-2 has not been mapped, but may involve the ectodomain. Proposed interaction points are indicated by red zig-zag lines. Myr: Nef myristoylationl; gpi: glycosyl-phosphatidylinositol anchor.