IFN-induced antiviral protein which inhibits the entry of viruses to the host cell cytoplasm, permitting endocytosis, but preventing subsequent viral fusion and release of viral contents into the cytosol. Active against multiple viruses, including influenza A virus, SARS coronavirus (SARS-CoV), Marburg virus (MARV), Ebola virus (EBOV), Dengue virus (DNV) and West Nile virus (WNV). Can inhibit: influenza virus hemagglutinin protein-mediated viral entry, MARV and EBOV GP1,2-mediated viral entry and SARS-CoV S protein-mediated viral entry. Also implicated in cell adhesion and control of cell growth and migration. Plays a key role in the antiproliferative action of IFN-gamma either by inhibiting the ERK activation or by arresting cell growth in G1 phase in a p53-dependent manner. Acts as a positive regulator of osteoblast differentiation. Interacts with CD81. Part of a complex composed of CD19, CR2/CD21, CD81 and IFITM1/CD225 in the membrane of mature B-cells. Interacts with CAV1; this interaction enhances the ability of CAV1 in inhibiting ERK activation. Predominantly expressed in nascent primordial germ cells, as well as in gonadal germ cells. In migrating PGCs, expression is first detected during germ cell differentiation. Palmitoylation on membrane-proximal cysteines controls clustering in membrane compartments and antiviral activity. Belongs to the CD225/Dispanin family. It has been previously shown that mediates migration of early primordial germ cells (PGCs) (PubMed:16326387). But according to PubMed:16326387, have no detectable effects on development of the germ line or on the generation of live young, hence, is not essential for PGC migration.