Interferon regulatory factor (IRF)

Interferon regulatory factors (IRFs) are a family of nine mammalian transcription factors (IRF1–IRF9) that serve as master regulators of the immune system, particularly in the induction of type I interferons and pro-inflammatory cytokines [1, 3]. These proteins share a conserved N-terminal DNA-binding domain that recognizes specific DNA sequences known as interferon-stimulated response elements (ISREs), allowing them to modulate gene expression in response to viral infections and other immune stimuli [2, 5]. Beyond their roles in innate and adaptive immunity, IRFs are critical for cell cycle regulation, apoptosis, and the differentiation of various immune cell lineages, such as dendritic cells and B cells [3, 4]. Dysregulation of IRF activity is a hallmark of many diseases; for example, overactivation of IRF5 and IRF7 is associated with autoimmune disorders like systemic lupus erythematosus, while IRF4 is a key oncogenic driver in hematological malignancies such as multiple myeloma [6, 8, 14]. Therapeutic targeting of IRFs is an active area of drug development, employing strategies such as direct small-molecule inhibition, proteolysis-targeting chimeras (PROTACs), and indirect modulation via upstream kinases like TBK1 or IRAK4 [1, 6, 15]. Immunomodulatory drugs (IMiDs) like lenalidomide exert their anti-cancer effects in part by inducing the degradation of IRF4 through the cereblon E3 ubiquitin ligase complex [6]. While targeting IRFs offers significant potential for treating cancer and inflammatory diseases, challenges remain regarding the specificity of inhibitors and the potential for broad immunosuppression or impaired antiviral defenses [8, 10]. Monitoring IRF expression levels and genetic polymorphisms serves as a valuable biomarker strategy for patient stratification and assessing therapeutic efficacy [1, 14].

Other names

IRF familyInterferon regulatory factor proteinsIRF1IRF2IRF3IRF4IRF5IRF6IRF7IRF8IRF9

Drugs targeting IRFs act through several mechanisms, including direct inhibition of DNA-binding or protein-protein interaction domains, targeted proteasomal degradation via E3 ligase recruitment (e.g., IMiDs and PROTACs), and indirect modulation by inhibiting upstream activating kinases such as TBK1, IKK, or IRAK4 [1, 6, 8, 15].