Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Nuclear factor of activated T-cells (NFAT), and Activator protein 1 (AP-1) transcription factor pathways (NF-κB, NFAT, and AP-1)

The NF-kappa-B (NF-κB), Nuclear factor of activated T-cells (NFAT), and Activator protein 1 (AP-1) pathways are fundamental transcription factor systems that coordinate the cellular response to external stimuli (Oeckinghaus & Ghosh, 2009). NF-κB serves as a primary mediator of inflammatory and innate immune responses, activated by various cytokines and toll-like receptors, while NFAT is a calcium-responsive factor essential for the development and activation of T-lymphocytes (Hogan et al., 2003). AP-1 is a dimeric complex that integrates signals from mitogen-activated protein kinase (MAPK) pathways to control cell proliferation, differentiation, and apoptosis (Hess et al., 2004). These three pathways frequently converge on the promoters of critical immune genes, such as interleukin-2, to ensure robust and specific gene induction during an immune challenge (Macian et al., 2001). Chronic overactivation of these pathways is strongly linked to the pathogenesis of autoimmune diseases, chronic inflammation, and oncogenesis. Therapeutic intervention often involves inhibiting these pathways to treat transplant rejection and inflammatory conditions, using drugs like calcineurin inhibitors and corticosteroids. However, because these factors are ubiquitously expressed and control vital homeostatic processes, targeting them can lead to significant side effects, including systemic immunosuppression and metabolic dysfunction.

Other names

NF-kappaBNF-ATAP1Rel familyJun/Fos complexNuclear factor of activated T-cellsNuclear factor kappa BActivator protein 1

Drugs targeting these pathways act through several mechanisms: calcineurin inhibitors (e.g., cyclosporine) prevent NFAT dephosphorylation and nuclear translocation; proteasome inhibitors (e.g., bortezomib) prevent the degradation of IκB, thereby sequestering NF-κB in the cytoplasm; and glucocorticoids (e.g., dexamethasone) inhibit NF-κB and AP-1 activity through direct protein-protein interactions and induction of inhibitory proteins like IκBα (Müller & Rao, 2010; Oeckinghaus & Ghosh, 2009).