IRF3 Rabbit Polyclonal Antibody

Interferon Regulatory Factor 3 (IRF3) is a pivotal transcription factor within the innate immune system that serves as a master regulator of type I interferon (IFN-I) production in response to viral and bacterial infections. Under basal conditions, IRF3 resides in the cytoplasm in an inactive, auto-inhibited state, but upon recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors such as TLR3, TLR4, or cytosolic sensors like RIG-I and MDA5, it undergoes phosphorylation at multiple serine and threonine residues in its C-terminal domain by upstream kinases including TBK1 and IKKε. This phosphorylation triggers a conformational change that promotes IRF3 dimerization, nuclear translocation, and subsequent binding to interferon-stimulated response elements (ISREs) in the promoters of target genes, thereby initiating the transcription of critical antiviral cytokines like IFN-β and various interferon-stimulated genes (ISGs) that establish an antiviral state; furthermore, IRF3 activity is tightly controlled through negative feedback mechanisms involving ubiquitination and proteasomal degradation to prevent excessive inflammation, highlighting its essential role as a central node in host defense signaling pathways.