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. 2022 Aug 25;13:971674. doi: 10.3389/fimmu.2022.971674

Figure 1.

Figure 1

The main transduction pathway of IFN signaling. (A) IFN first binds to the heterodimers of IFNAR1 and IFNAR2, causing phosphorylation of JAK1 and TYK2, followed by phosphorylation of STAT1 and STAT2. Phosphorylated STATs form heterodimers that enter the nucleus and bind to IRF9 to form ISGF3, which subsequently binds to the transcriptional enhancer ISRE, triggering transcriptional induction of ISG. (B) Type II IFNs first bind to IFNGR1 and IFNGR2, causing phosphorylation of STAT1 and STAT2. The phosphorylated STAT forms a heterodimer that enters the nucleus and binds to IRF9 to form ISGF3. ISGF3 subsequently binds to the transcriptional enhancer ISRE, triggering the transcriptional induction of ISG. In addition, phosphorylated STAT1 homodimers, STAT3 homodimers and STAT1-STAT3 heterodimers enter the nucleus. These dimers bind to GAS elements to induce transcription factor production and initiate a second wave of gene expression; (C) Type III IFN binds to IFNLR1 and IL10R2, followed by the same response as the type I IFN signaling cascade.