Receptor subunit for interferon gamma/INFG that plays crucial roles in antimicrobial, antiviral, and antitumor responses by activating effector immune cells and enhancing antigen presentation (, PubMed:20926559, PubMed:27286456). Associates with transmembrane accessory factor IFNGR2 to form a functional receptor (PubMed:2530582, PubMed:2532365, PubMed:2137461, PubMed:2531896, PubMed:2530216). Upon ligand binding, the intracellular domain of IFNGR1 opens out to allow association of downstream signaling components JAK1 and JAK2. In turn, activated JAK1 phosphorylates IFNGR1 to form a docking site for STAT1. Subsequent phosphorylation of STAT1 leads to its dimerization, translocation to the nucleus, and stimulation of target gene transcription (PubMed:19889125). STAT3 can also be activated in a similar manner although activation seems weaker (PubMed:15284232). IFNGR1 intracellular domain phosphorylation also provides a docking site for SOCS1 that regulates the JAK-STAT pathway by competing with STAT1 binding to IFNGR1 (PubMed:15522878). Monomer. Heterodimer with IFNGR2, to form the IFNG receptor complex. Interacts with JAK1. Interacts (when phosphorylated) with STAT1 (By similarity). Interacts with SOCS1 (PubMed:15522878). Phosphorylated at Ser/Thr residues. Phosphorylation of Tyr-445 is required for IFNG receptor signal transduction. Influenza virus infection leads to phosphorylation in a CSNK1A1-dependent manner. Ubiquitinated after phosphorylation in a CSNK1A1-dependent manner, leading to the lysosome-dependent degradation. Proteasomally degraded through 'Lys-48'-mediated ubiquitination. Ubiquitination is necessary for efficient IFNGR1 signaling. Deletion mutants show shortened lifespan and enhanced intestinal tumorigenesis. These tumors exhibit increased inflammation (PubMed:27286456). Loss of STAT1 signaling pathway activation is also observed (PubMed:19889125). After viral infection such as junin virus, mice develop disseminated infection and severe disease (PubMed:20926559). Belongs to the type II cytokine receptor family. Truncated N-terminus.