ATF2 (activating transcription factor 2) is a basic leucine zipper (bZIP) protein and member of the activator protein-1 (AP-1) family (Wagner et al. 2001). The basic region of ATF2 binds DNA while the leucine zipper region allows dimerization with partners. ATF2 is a histone acetyltransferase (HAT), which specifically acetylates histones H2B and H4 in vitro. ATF2 is sequentially phosphorylated on threonine residues T69 and T71 by protein kinases ERK1/2 and p38 (van Dam et al. 1995, Livingstone et al. 1995, Ouwens et al. 2002, Baan et al. 2009). This phosphorylated form has increased HAT activity (Kawasaki et al. 2000).