Neddylation of a breast cancer-associated protein recruits a class III histone deacetylase that represses NFκB-dependent transcription

Neddylation has an important role in ubiquitin- mediated protein degradation through modification of cullins, which are the main substrates for NEDD8 modification. Here, we show that breast cancer-associated protein 3 (BCA3) is a NEDD8 substrate. BCA3 suppressed NF kappa B-dependent transcription through its ability to bind to p65 and the cyclin D1 promoter in a neddylation- dependent manner. Transcriptional suppression mediated by BCA3 may be attributed to the ability of neddylated BCA3 to recruit SIRT1, a class III histone deacetylase. Silencing of endogenous BCA3 in DU145 and MCF7 cells enhanced NF kappa B transcription and inhibited tumour necrosis factor (TNF) alpha-induced apoptosis. Conversely, BCA3 silencing could be reversed by over-expression of wild-type BCA3 and SENP8, a NEDD8-specific protease, but not by neddylation- deficient BCA3 or a SENP8 mutant. These results provide a crucial link between neddylation and transcriptional regulation by SIRT1, a NAD-dependent histone deacetylase that prolongs life span in yeast and worms.