Fig. 1.

The ING family protein domains and their functions. The PIP box binds to PCNA and promotes ING1-mediated apoptosis. The PBD and NCR/LID binds to SAP30, HDAC and HAT, and regulates their activities. The LZL domain of ING2 is required for DNA repair and induction of apoptosis. The NLS binds to the karyopherin-α and β transporter proteins for targeting ING proteins to their functional site, the nucleus and/or the nucleolus for ING1. It has also been reported to mediate interaction with p53 [77]. The PHD motif plays a role in HAT and/or HDAC activity, which can then regulate transcription at specific loci. Both PHD and PBR bind to PtdInsPs, suggesting that PBR may also be involved in chromatin remodeling and transcription regulation