IFNGR2

IFNGR2 is the signal-transducing chain of the heterodimeric IFN-γ receptor, required to couple IFN-γ engagement to downstream JAK1/2–STAT1 signaling and the cellular IFN-γ response (PMID:29106381). In contrast to IFNGR-1, which is endocytosed and translocated to the nucleus where it associates with activated STAT1α after ligand stimulation, IFNGR-2 remains predominantly at the cell surface (PMID:10888113). Productive surface expression depends on N-glycosylation quality control in the secretory pathway: a misfolding microinsertion mutation produces an abnormally high-molecular-weight, retained protein, and pharmacological modification of N-glycosylation restores both normal MW and IFN-γ responsiveness (PMID:18625743). Loss-of-function mutations in IFNGR2 cause Mendelian susceptibility to mycobacterial disease, and the gene is also subject to dosage effects: heterozygous frameshift alleles are non-dominant-negative but produce haploinsufficiency that more severely impairs IFN-γ responses in lymphoid than myeloid cells, tracking with lower lymphoid IFNGR2 expression (PMID:29106381, PMID:23161749, PMID:31497017). Receptor output is further tuned post-translationally and transcriptionally — palmitoylation at C261, driven by ACOT11-mediated fatty acid accumulation, inhibits JAK-STAT signaling and dampens IL-1β maturation in inflammatory macrophages (PMID:40715698), and melatonin–MT1–HSF1 signaling transcriptionally represses IFNGR2 to suppress canonical IFN-γ signaling (PMID:35184395). Transcription of the gene is directed by a TATA- and CAAT-less promoter containing Sp1, AP-2, NF1, EGR, and NF-κB elements (PMID:8972742).

1. 1996 Medium

   Before the regulation of IFNGR2 was understood, its promoter architecture was defined, establishing how the gene is transcribed and which factors could control its expression.

   Evidence Genomic cloning and luciferase reporter deletion assays of the mouse gene in transfected CHO cells

   PMID:8972742

   Open questions at the time

   • Functional contribution of individual Sp1/NF-κB sites not dissected
   • Human promoter not directly characterized
   • No link to cell-type-specific expression differences
2. 2000 Medium

   It was unknown how the two receptor chains behave after ligand binding; this showed an asymmetric fate in which IFNGR-1 internalizes and reaches the nucleus with STAT1α while IFNGR-2 stays at the surface, framing IFNGR2 as a stably surface-resident signaling chain.

   Evidence Reciprocal immunoprecipitation and immunofluorescence after IFN-γ stimulation of WISH cells

   PMID:10888113

   Open questions at the time

   • Functional consequence of differential trafficking not established
   • Mechanism retaining IFNGR-2 at the surface unknown
   • Single lab, single cell type
3. 2008 High

   The question of what controls IFNGR2 surface delivery was answered by showing that N-glycosylation quality control governs trafficking — a misfolding mutant is retained, and chemically altering glycosylation rescues surface expression and IFN-γ responsiveness.

   Evidence Transfection, surface MW analysis, IFN-γ response assays, and pharmacological complementation with N-glycosylation-modifying compounds

   PMID:18625743

   Open questions at the time

   • Specific glycosylation sites and chaperones not mapped
   • Generality across other IFNGR2 mutations untested
4. 2012 Medium

   Whether partial IFNGR2 loss matters was addressed by showing heterozygous frameshift alleles cause non-dominant-negative haploinsufficiency that selectively impairs lymphoid IFN-γ responses, linking gene dosage to cell-type-specific immunity.

   Evidence Exome/Sanger sequencing and IFN-γ response assays across B cells, CD4+ T cells, monocytes, and MDMs from heterozygous relatives

   PMID:23161749

   Open questions at the time

   • Mechanism of cell-type expression differences not resolved
   • Clinical penetrance of haploinsufficiency unclear
5. 2013 Low

   The role of IFNGR2-dependent IFN-γ signaling in shaping T helper differentiation was probed, indicating that signaling in antigen-presenting cells suppresses Th17 generation.

   Evidence Co-culture of patient monocytes and CD4+ T cells measuring IL-17 production

   PMID:23459074

   Open questions at the time

   • Single patient-derived cells, single method
   • Molecular mediator of Th17 suppression not identified
   • Not independently confirmed
6. 2017 Medium

   The signal-transducing identity of IFNGR2 was confirmed by a homozygous frameshift that abolishes protein and downstream IFN-γ signaling, cementing its requirement for IFN-γ-mediated immunity.

   Evidence Whole-exome sequencing and downstream signaling assays in patient fibroblasts

   PMID:29106381

   Open questions at the time

   • Structural basis of signal transduction not addressed
   • Single family
7. 2019 Medium

   The allelic spectrum of disease-causing variants was extended by a splice variant producing an in-frame three-residue deletion in the extracellular fibronectin type III domain, linking the ligand-binding region to mycobacterial susceptibility.

   Evidence Exome sequencing with RT-PCR/cDNA confirmation in patient fibroblasts and blood

   PMID:31497017

   Open questions at the time

   • Effect of the deletion on ligand binding not biochemically measured
   • Single patient
8. 2022 Medium

   How environmental/hormonal signals modulate IFN-γ responsiveness was addressed by showing melatonin acts through MT1–HSF1 to transcriptionally repress IFNGR2, dampening canonical JAK1/2–STAT1–IRF7 signaling and IL-1β.

   Evidence RNA-seq, metabolomics, genetic manipulation of MT1/HSF1/GSK3β, and an in vivo infection model in macrophages

   PMID:35184395

   Open questions at the time

   • Direct HSF1 binding at the IFNGR2 promoter not shown
   • Physiological relevance of melatonin levels uncertain
9. 2024 Low

   A naturally occurring coding variant was shown to amplify rather than impair signaling, selectively enhancing IFN-γ-driven STAT1 phosphorylation in transitional B cells.

   Evidence SNP genotyping and STAT1 phosphorylation assays in cell lines and primary B cells

   PMID:38972102

   Open questions at the time

   • Single SNP, limited mechanistic depth
   • Biochemical basis of enhanced phosphorylation unknown
   • Not independently confirmed
10. 2025 Medium

    A post-translational brake on receptor output was defined, with ACOT11-driven fatty acid accumulation promoting palmitoylation of IFNGR2 at C261 to inhibit JAK-STAT signaling and IL-1β maturation.

    Evidence GWAS, ACOT11 overexpression, site-directed C261 palmitoylation mutagenesis, signaling assays, and LPS sepsis model

    PMID:40715698

    Open questions at the time

    • Palmitoyltransferase responsible not identified
    • How palmitoylation mechanistically disrupts JAK engagement unresolved

• How surface-resident IFNGR2 structurally couples ligand engagement to JAK1/2 activation, and how its glycosylation, palmitoylation, and transcriptional controls are integrated in vivo, remains unresolved.
• No structural model of the active receptor complex in the corpus
• Direct JAK1/2 contact sites on IFNGR2 not mapped
• Integration of competing regulatory inputs untested