RelB

RelB is a member of the NF-κB transcription factor family and functions as a key regulator of immune homeostasis, antigen-presenting cell activity, and lymphoid tissue organization^[4][1]. Mechanistically, RelB is the principal transcriptional component of the non-canonical NF-κB pathway, where NF-κB-inducing kinase (NIK) and IKKα promote processing of p100 into p52, leading to formation and nuclear translocation of RelB:p52 heterodimers that regulate distinct target genes involved in lymphoid organogenesis, lymphocyte trafficking, and immune regulation^[1][5]. In dendritic cells, RelB is highly expressed and is required for dendritic cell maturation, antigen presentation, and T-cell activation, highlighting its central role in adaptive immune responses^[2]. Disease relevance arises from the broad involvement of non-canonical NF-κB signaling in inflammatory, autoimmune, and malignant disorders, while RelB-dependent transcriptional programs contribute to the regulation of immune response genes and maintenance of immune homeostasis^[1][3][6]. Compared with the closely related NF-κB subunit RelA (p65), which predominantly mediates canonical NF-κB signaling through p50:RelA dimers, RelB preferentially forms transcriptionally active complexes with p52 and controls a distinct set of genes associated with developmental and homeostatic immune functions^[1][5]. Experimental studies further indicate that RelB can modulate inflammatory gene expression by competing with RelA for κB-binding sites, providing a mechanistic basis for functional divergence among NF-κB family members^[6]. For research applications, pharmacological strategies targeting NF-κB signaling, including inhibitors of upstream kinases and nuclear NF-κB activity, are widely used to investigate RelB-regulated pathways in immunity, inflammation, and cancer models^[3].