InterPro domain: IPR005343

In Saccharomyces cerevisiae, Noc2 forms a nucleolar complex with Mak21 that binds to 90S and 66S pre-ribosomes. It also forms a nuclear complex with Noc3 that binds to 66S pre-ribosomes [ 1 ]. Both complexes mediate intranuclear transport of ribosomal precursors [ 2 ].

In humans, Noc2 (also known as NIR) acts as an inhibitor of histone acetyltransferase activity; prevents acetylation of all core histones by the EP300/p300 histone acetyltransferase at p53/TP53-regulated target promoters in a histone deacetylases (HDAC)-independent manner. It also acts as a transcription corepressor of p53/TP53- and TP63-mediated transactivation of the p21/CDKN1A promoter. It is involved in the regulation of p53/TP53-dependent apoptosis [ 2 , 3 , 4 ].

1. Maturation and intranuclear transport of pre-ribosomes requires Noc proteins. Cell 105, 499-509
2. NIR is a novel INHAT repressor that modulates the transcriptional activity of p53. Genes Dev. 19, 2912-24
3. NIR, an inhibitor of histone acetyltransferases, regulates transcription factor TAp63 and is controlled by the cell cycle. Nucleic Acids Res. 38, 3159-71
4. Aurora B interacts with NIR-p53, leading to p53 phosphorylation in its DNA-binding domain and subsequent functional suppression. J. Biol. Chem. 286, 2236-44