The tetrameric receptor complex for IFNγ consists of two subunits, IFNGR1 (IFNγ Rα) and IFNGR2 (IFNγ Rβ), through which the dimeric IFN-γ exerts its biological functions, including antiviral, antiproliferation and immune-modulatory activity in mammals. Both IFNGR1 and IFNGR2 are single transmembrane proteins belonging to the class II cytokine family. FNGR1, widely expressed in most host cells, is essential for IFNγ binding, receptor trafficking, and signal transduction. IFNGR1 possesses an intracellular Janus tyrosine kinase (JAK) 1 binding site, a signal transducer and activator of transcription 1 (STAT1) binding site. The resulting STAT1 homodimers translocate from the cytoplasm to the nucleus and bind to the interferon-gamma activated sequence (GAS) promoter to induce expression of downstream interferon stimulated genes (ISGs).