The RELA gene at 11q13.1 codes for the 551 amino acid transcription factor p65 a common subunit of the NF-kappa-B transcription factor. In the cytoplasm it has been found in an inactive form complexed to an inhibitor (I-kappa-B). There are four isoforms generated by alternative splicing and there is complex post translation modification. Its different dimer combinations act as transcriptional activators or repressors. Indeed the heterodimeric complex form of NF-kappa-B with the first 433 amino acids of nuclear factor NF-kappa-B p105 subunit (p50) is most abundant and a transcriptional activator although NF-kappa-B/nuclear factor NF-kappa-B p105 subunit and homodimers of transcription factor p65 (involved in activation of IL-8 expression) are also active.