TIP60 belongs to the MYST family of histone acetyl transferases （HATs） and was originally isolated as an HIV-1 TAT interactive protein. HATs play important roles in regulating chromatin remodeling，transcription and other nuclear processes by acetylating histone and non-histone proteins. TIP60 has been shown to play a role in DNA repair and apoptosis and is thought to play an important role in signal transduction and autophagy. In case of HIV-1 infection，interaction with the viral Tat protein leads to TIP60 polyubiquitination and targets it to degradation. Also，TIP60 contains a chromodomain. TIP60 is a catalytic subunit of the NuA4 histone acetyltransferase complex. The NuA4 HAT complex plays a role in transcriptional activation of select genes mainly by acetylation of nucleosomal histone H4 and H2A，which influence nucleosome-DNA interaction and promotes interaction of the modified histones with other proteins that could regulate transcription positively. This complex also involves in the activation of transcriptional programs associated with oncogene and proto-oncogene mediated growth induction，tumor suppressor mediated growth arrest and replicative senescence，DNA repair and apoptosis.
