Regulatory subunit of the ATP-dependent NoRC-1 and NoRC-5 ISWI chromatin remodeling complexes, which form ordered nucleosome arrays on chromatin and facilitate access to DNA during DNA-templated processes such as DNA replication, transcription, and repair (PubMed:11532953). Both complexes regulate the spacing of nucleosomes along the chromatin and have the ability to slide mononucleosomes to the center of a DNA template (PubMed:11532953). Directly stimulates the ATPase activity of SMARCA5 in the NoRC-5 ISWI chromatin remodeling complex (By similarity). The NoRC-1 ISWI chromatin remodeling complex has a lower ATP hydrolysis rate than the NoRC-5 ISWI chromatin remodeling complex (By similarity). Within the NoRC-5 ISWI chromatin remodeling complex, mediates silencing of a fraction of rDNA by recruiting histone-modifying enzymes and DNA methyltransferases, leading to heterochromatin formation and transcriptional silencing (PubMed:11532953). In the complex, it plays a central role by being recruited to rDNA and by targeting chromatin modifying enzymes such as HDAC1, leading to repress RNA polymerase I transcription (PubMed:12198165, PubMed:16085498). Recruited to rDNA via its interaction with TTF1 and its ability to recognize and bind histone H4 acetylated on 'Lys-16' (H4K16ac), leading to deacetylation of H4K5ac, H4K8ac, H4K12ac but not H4K16ac (PubMed:11532953, PubMed:16085498). Specifically binds pRNAs, 150-250 nucleotide RNAs that are complementary in sequence to the rDNA promoter; pRNA-binding is required for heterochromatin formation and rDNA silencing (PubMed:16678107, PubMed:18600236). Component of the NoRC-1 ISWI chromatin remodeling complex at least composed of SMARCA1 and BAZ2A/TIP5, which regulates the spacing of histone octamers on the DNA template to facilitate access to DNA (By similarity). Within the NoRC-1 ISWI chromatin remodeling complex interacts with SMARCA1; the interaction is direct (By similarity). Component of the NoRC-5 ISWI chromatin remodeling complex (also called the NoRC nucleolar-remodeling complex), at least composed of SMARCA5/SNF2H and BAZ2A/TIP5, which regulates the spacing of histone octamers on the DNA template to facilitate access to DNA (PubMed:11532953). Within the NoRC-5 ISWI chromatin remodeling complexes interacts with SMARCA5/SNF2H; the interaction is direct (PubMed:11532953, PubMed:16085498). Interacts with TTF1; the interaction is required for recruitment of the NoRC-5 ISWI chromatin remodeling complex to rDNA (PubMed:11532953, PubMed:15292447). Interacts with HDAC1 (PubMed:12198165, PubMed:16085498). Interacts with SIN3A (PubMed:12198165). Interacts with DNMT1 and DNM3B (PubMed:16085498). Interacts with BEND3 and USP21 (By similarity). Co-localizes with the basal RNA polymerase I transcription factor UBF in the nucleolus. The bromo domain and the PHD-type zinc finger recognize and bind histone H4 acetylated on 'Lys-16' (H4K16ac). These 2 domains play a central role in the recruitment of chromatin silencing proteins such as DNMT1, DNMT3B and HDAC1. The MBD (methyl-CpG-binding) domain, also named TAM domain, specifically recognizes and binds a conserved stem-loop structure the association within pRNA. Binding to pRNA induces a conformational change of BAZ2A/TIP5 and is essential for targeting the NoRC complex to the nucleolus. Ubiquitinated. Deubiquitinated by USP21 leading to its stabilization. Acetylation at Lys-672 by KAT8/MOF promotes its dissociation from pRNA, affecting heterochromatin formation, nucleosome positioning and rDNA silencing. Deacetylation by SIRT1 in late S phase enhances pRNA-binding, allowing de novo DNA methylation and heterochromatin formation. Acetylation is high during S phase and declines to background levels in late S phase when the silent copies of rRNA genes are replicated. Belongs to the WAL family.