NF-κB1 p105/p50 Recombinant Rabbit mAb (S-3588-77)

NF-κB1 p105/p50 is a critical transcription factor subunit belonging to the Rel/NF-κB family, encoded by the NFKB1 gene in humans. It exists primarily in two distinct forms: the precursor protein p105 and its processed product p50. The p105 precursor (105 kDa) contains an N-terminal Rel homology domain (RHD) responsible for DNA binding, dimerization, and nuclear localization, followed by a C-terminal ankyrin repeat domain that functions as an inhibitory IκB-like structure, keeping p105 sequestered in the cytoplasm under basal conditions. Through constitutive or signal-induced proteasomal processing, p105 undergoes limited proteolysis to generate the mature p50 subunit (50 kDa), which lacks the inhibitory C-terminal domain and can translocate to the nucleus upon activation. The p50 protein typically forms homodimers or heterodimers with other NF-κB family members, most commonly p65 (RelA), to bind κB DNA enhancer sequences and regulate transcription of genes involved in immune responses, inflammation, cell survival, and proliferation. Notably, p50 homodimers can act as transcriptional repressors when competing for DNA binding sites or recruiting co-repressor complexes, adding regulatory complexity to NF-κB signaling. The NF-κB1 pathway is activated by diverse stimuli including pro-inflammatory cytokines (TNF-α, IL-1), pathogen-associated molecular patterns (PAMPs), and stress signals, with dysregulation implicated in autoimmune diseases, chronic inflammation, and various cancers.