BAZ2A
Description
The BAZ2A (bromodomain adjacent to zinc finger domain 2A) is a protein-coding gene located on chromosome 12.
Bromodomain adjacent to zinc finger domain protein 2A (BAZ2A) is a protein encoded by the BAZ2A gene in humans. It is involved in chromatin remodeling, acting as a regulatory subunit in two distinct ISWI chromatin remodeling complexes: NoRC-1 and NoRC-5.
BAZ2A is a regulatory subunit of the ATP-dependent NoRC-1 and NoRC-5 ISWI chromatin remodeling complexes. These complexes play a crucial role in organizing nucleosomes on chromatin, which facilitates access to DNA for various processes like DNA replication, transcription, and repair. BAZ2A directly stimulates the ATPase activity of SMARCA5 within the NoRC-5 complex. The NoRC-1 complex exhibits a lower ATP hydrolysis rate compared to the NoRC-5 complex. Within the NoRC-5 complex, BAZ2A mediates silencing of a fraction of ribosomal DNA (rDNA) by recruiting histone-modifying enzymes and DNA methyltransferases, leading to heterochromatin formation and transcriptional silencing. This protein acts as a central component in the complex, being recruited to rDNA through its interaction with TTF1 and its ability to bind to histone H4 acetylated on lysine 16 (H4K16ac). This recruitment results in deacetylation of H4K5ac, H4K8ac, and H4K12ac, but not H4K16ac. BAZ2A also binds specifically to pRNAs, which are small RNAs complementary to the rDNA promoter, and this binding is crucial for heterochromatin formation and rDNA silencing.
BAZ2A is also known as TIP5, WALp3.
