Acetylation of RELA/p65 subunit differentially regulates distinct biological activities of the NF-kB transcription factor complex. The acetylation enables increased DNA binding and transcriptional activity by NF-kB, leading to up-regulated IL6 (interleukin 6), IL10, IL12p35, IL12p40 and IL23p19 production (Geijtenbeek and Gringhuis 2009). Acetyltransferases p300 and CBP are involved in the acetylation of RELA on multiple sites including lysines 122, 123, 218, 221 and 310. Acetylation of lysine 221 by p300/CBP increases the DNA binding affinity of RELA for the IkB enhancer and, together with acetylation of lysine 218, impairs assembly of RELA with newly synthesized IkBalpha, which shuttles in and out of the nucleus. Acetylation of lysine 310 does not modulate DNA binding or IkBalpha assembly but markedly enhances the transcriptional activity of NF-kB (Chen et al. 2002, 2005).