Expressed in monocytes, lymphocytes, and placenta, human Interferon Gamma Receptor Complex (Type II Cytokine Family Receptor) is a Ser/Thr phosphorylated type I membrane protein heteromeric receptor for IFN-gamma, composed of IFNGR1 and IFNGR2, that activates macrophages in host defenses. In mediating innate immune responses to viral infection, binding of IFN-gamma activates JAK kinases leading to tyrosine phosphorylation of STAT1 and STAT2. IFNGR1 constitutes the receptor ligand-binding alpha chain while the integral accessory factor IFNGR2 is required for signal transduction and may interact with GAF, JAK1, and/or JAK2. (NCI) [ ]