Fig. 1. Acetylation of a variety of proteins by acetylases affects their activity in different ways. The activity of acetylases is regulated, at least in vitro, by kinases involved in DNA repair (DNA–PK) and cell cycle progression (cyclin E–CDK). Acetylated targets include histones, nuclear acetylases (P/CAF and p300), transcription factors [e.g. HMGI(Y), E2F1, p53 and TCF], the nuclear import factor, importin-α and α–tubulin. Acetylation has many consequences, including effects on DNA binding, protein stability and protein–protein interaction. Ac, acetylation; p, phosphorylation.