Key transcriptional regulator of type I interferon (IFN)-dependent immune responses and plays a critical role in the innate immune response against DNA and RNA viruses. Regulates the transcription of type I IFN genes (IFN-alpha and IFN-beta) and IFN-stimulated genes (ISG) by binding to an interferon-stimulated response element (ISRE) in their promoters (PubMed:17574024, PubMed:32972995). Can efficiently activate both the IFN-beta (IFNB) and the IFN-alpha (IFNA) genes and mediate their induction via both the virus-activated, MyD88-independent pathway and the TLR-activated, MyD88-dependent pathway. Induces transcription of ubiquitin hydrolase USP25 mRNA in response to lipopolysaccharide (LPS) or viral infection in a type I IFN-dependent manner (By similarity). Required during both the early and late phases of the IFN gene induction but is more critical for the late than for the early phase. Exists in an inactive form in the cytoplasm of uninfected cells and following viral infection, double-stranded RNA (dsRNA), or toll-like receptor (TLR) signaling, becomes phosphorylated by IKBKE and TBK1 kinases. This induces a conformational change, leading to its dimerization and nuclear localization where along with other coactivators it can activate transcription of the type I IFN and ISG genes. Can also play a role in regulating adaptive immune responses by inducing PSMB9/LMP2 expression, either directly or through induction of IRF1. Binds to the Q promoter (Qp) of EBV nuclear antigen 1 a (EBNA1) and may play a role in the regulation of EBV latency. Can activate distinct gene expression programs in macrophages and regulate the anti-tumor properties of primary macrophages (By similarity) (PubMed:11073981, PubMed:12374802, PubMed:15361868, PubMed:17404045). In the absence of viral infection, maintained as a monomer in an autoinhibited state and phosphorylation disrupts this autoinhibition leading to the liberation of the DNA-binding and dimerization activities and its nuclear localization where it can activate type I IFN and ISG genes. Monomer. Homodimer; phosphorylation-induced. Heterodimer with IRF3 (PubMed:17574024). Interacts with TICAM1 and TICAM2. Interacts with MYD88 and TRAF6. Interacts with TRIM35 (PubMed:25907537, PubMed:11073981, PubMed:11314014, PubMed:14517278, PubMed:14739303, PubMed:15361868, PubMed:15492225). Interacts with NMI; the interaction is direct and leads to the inhibition of IRF7-mediated type I IFN production (By similarity). (Microbial infection) Interacts with Epstein-Barr virus LF2 and LMP1. (Microbial infection) Interacts with rotavirus A NSP1; this interaction leads to the proteasome-dependent degradation of IRF7. (Microbial infection) Interacts with human herpes virus 8/HHV-8 proteins ORF45 and vIRF-1. (Microbial infection) Interacts with human T-cell leukemia virus 1/HTLV-1 protein HBZ. (Microbial infection) Interacts with Seneca Valley virus protease 3C; this interaction is involved in the suppression of IRF7 expression and phosphorylation by the virus. (Microbial infection) Interacts with ebolavirus VP35; this interaction mediates the sumoylation of IRF7 and contributes to the viral inhibition of IFN-type I production. (Microbial infection) Interacts with severe fever with thrombocytopenia syndrome virus (SFTSV) NSs; this interaction sequesters IRF7 in NSs-induced cytoplasmic inclusion bodies. The phosphorylated and active form accumulates selectively in the nucleus. Expressed predominantly in spleen, thymus and peripheral blood leukocytes. By type I interferon (IFN) and viruses. Acetylation inhibits its DNA-binding ability and activity. In response to a viral infection, phosphorylated on Ser-477 and Ser-479 by TBK1 and IKBKE1. Phosphorylation, and subsequent activation is inhibited by vaccinia virus protein E3. In TLR7- and TLR9-mediated signaling pathway, phosphorylated by IRAK1. TRAF6-mediated ubiquitination is required for IRF7 activation (By similarity). TRIM35 mediates IRF7 'Lys-48'-linked polyubiquitination and subsequent proteasomal degradation (PubMed:25907537). Ubiquitinated by UBE3C, leading to its degradation (PubMed:21167755). Sumoylated by TRIM28, which inhibits its transactivation activity. (Microbial infection) Cleaved and inactivated by the protease 3C of enterovirus 71 allowing the virus to disrupt the host type I interferon production. (Microbial infection) Cleaved and inactivated by the protease 3C of human enterovirus 68D (EV68) allowing the virus to disrupt the host type I interferon production. 'Lys-48'-linked polyubiquitination and subsequent proteasomal degradation is NMI-dependent in response to Sendai virus infection. The disease is caused by variants affecting the gene represented in this entry. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Belongs to the IRF family.