RelA belongs to a family of transcription factors (NF-kappa-B (nuclear factor kappa from B cells) complex) that play a fundamental role in inflammatory and immune responses. The NF-kappa-B complex is composed of a heterodimer of a Rel family member (RelA, c-Rel, RelB) and either NF-kappa-B1 or NF-kappa-B2 subunits. RelA and NF-kappa-B1 are the most common heterodimeric pair. The NF-kappa-B complex is sequestered in the cytoplasm by inhibitory I-kappa-B proteins. Upon cellular activation, the ubiquitin-proteosome pathway degrades the I-kappa-B proteins allowing the NF-kappa-B complex to translocate to the nucleus and activate gene transcription.