Nuclear factor NF-kappa-B p105 subunit

NFKB1 encodes the p105 precursor and p50 subunit of nuclear factor NF-kappa-B, a pleiotropic transcription factor controlling immune response, inflammation, and apoptosis (UniProt: P19838). The protein functions as both a cytoplasmic inhibitor of NF-kappa-B complexes and a source of active p50, which dimerizes with RELA/p65 to bind kappa-B consensus sequences in immune response genes. NFKB1 is implicated in common variable immunodeficiency with autoimmunity (UniProt: P19838).

NFKB1 is upregulated in Alzheimer's disease brain tissue, with a mean log2 fold-change of 0.43 in post-mortem AD versus age-matched controls (Chaparral AD proteomics). This elevation suggests activation of NF-kappa-B signaling in AD pathology, consistent with neuroinflammatory mechanisms observed in the disease. The upregulation was detected across subcellular fractions in a TMT-labeled proteomic study, indicating a consistent signal rather than compartment-specific enrichment.