Reversible acetylation modulates p54nrb/NONO-mediated expression of the interleukin 8 gene.

The non-POU domain-containing octamer-binding protein (NONO, also referred to as p54nrb) is a multifunctional nuclear protein engaging in transcriptional regulation, mRNA splicing, nuclear retention of defective RNA, and DNA repair. Emerging evidence has demonstrated that p54nrb is subjected to various posttranslational modifications, including phosphorylation and methylation, which may be important regulators of its multifunction. However, among these modifications, direct evidence of p54nrb acetylation and its underlying mechanism remains unclear. In this study, we reported that lysine 371 of p54nrb was reversibly acetylated by the acetyltransferase general control non-depressible 5 (GCN5) and deacetylase sirtuin 1 (SIRT1), which was crucial for activity of p54nrb to inhibit interleukin-8 (IL-8) expression. Mechanistically, GCN5-mediated acetylation attenuates the recruitment of p54nrb on its core binding motif within the IL-8 gene promoter, preferentially increasing the expression of the IL-8 gene. In contrast, deacetylation by SIRT1 reverses this process. Altogether, our data suggest that reversible acetylation is an important switch for the multiple nuclear functions of p54nrb/NONO.