Core component of the DBIRD complex, a multiprotein complex that acts at the interface between core mRNP particles and RNA polymerase II (RNAPII) and integrates transcript elongation with the regulation of alternative splicing: the DBIRD complex affects local transcript elongation rates and alternative splicing of a large set of exons embedded in (A + T)-rich DNA regions (By similarity). Inhibits SIRT1 deacetylase activity leading to increasing levels of p53/TP53 acetylation and p53-mediated apoptosis (By similarity). Inhibits SUV39H1 methyltransferase activity (PubMed:19218236). Mediates ligand-dependent transcriptional activation by nuclear hormone receptors (By similarity). Plays a critical role in maintaining genomic stability and cellular integrity following UV-induced genotoxic stress (By similarity). Regulates the circadian expression of the core clock components NR1D1 and ARNTL/BMAL1 (PubMed:23398316). Enhances the transcriptional repressor activity of NR1D1 through stabilization of NR1D1 protein levels by preventing its ubiquitination and subsequent degradation (PubMed:23398316). Represses the ligand-dependent transcriptional activation function of ESR2 (By similarity). Acts as a regulator of PCK1 expression and gluconeogenesis by a mechanism that involves, at least in part, both NR1D1 and SIRT1 (PubMed:24415752). Negatively regulates the deacetylase activity of HDAC3 and can alter its subcellular localization (PubMed:21030595). Positively regulates the beta-catenin pathway (canonical Wnt signaling pathway) and is required for MCC-mediated repression of the beta-catenin pathway (By similarity). Represses ligand-dependent transcriptional activation function of NR1H2 and NR1H3 and inhibits the interaction of SIRT1 with NR1H3 (By similarity). Plays an important role in tumor suppression through p53/TP53 regulation; stabilizes p53/TP53 by affecting its interaction with ubiquitin ligase MDM2 (PubMed:25732823). Represses the transcriptional activator activity of BRCA1 (By similarity). Inhibits SIRT1 in a CHEK2 and PSEM3-dependent manner and inhibits the activity of CHEK2 in vitro (By similarity). Component of the DBIRD complex (By similarity). Interacts with ZNF326/ZIRD; the interaction is direct (By similarity). Interacts (via N-terminus) with SIRT1, which inhibits the deacetylation of substrates (PubMed:21030595). Interacts (via N-terminus) with SUV39H1; this interaction abolishes the interaction with SIRT1 (PubMed:19218236). Component of a nuclear receptor-mediated transcription complex composed of at least ZNF335, CCAR2 and EMSY; the complex stimulates the transcription of nuclear receptor target genes such as SOX9 and HOXA1 (By similarity). Within the complex interacts with EMSY and interacts with ZNF335 (via C-terminus) (By similarity). Components of this complex may associate with components of a histone methylation complex to form a complex at least composed of ZNF335, HCFC1, CCAR2, EMSY, MKI67, RBBP5, ASH2L and WDR5 (By similarity). Within this complex, interacts with ASH2L (By similarity). Interacts with NR1D1 (PubMed:23398316). Interacts (via N-terminus) with ESR1 and ESR2 (By similarity). Interacts (via N-terminus) with HDAC3 (via C-terminus) (PubMed:21030595). Interacts with HDAC1 and MED2F (PubMed:21030595). Interacts with MCC (By similarity). Interacts (via N-terminus) with NR1H2 and NR1H3 in a ligand-independent manner (By similarity). Interacts with CSNK2A1 (By similarity). Interacts (via N-terminus) with p53/TP53 (PubMed:25732823). Interacts (via N-terminus) with BRCA1 (via the BRCT domains) (By similarity). Interacts (via N-terminus) with CHEK2 (via protein kinase domain) (By similarity). Interacts with PSEM3 (By similarity). Interacts (via N-terminus) with PSIA3 and SENP1 (By similarity). The sumoylated form shows a preferential interaction with SIRT1 as compared to its unmodified form (By similarity). Recruited to chromatin, post-UV irradiation. Sequestered to the cytoplasm in the presence of MCC. Translocated to the cytoplasm during UV-induced apoptosis. Acetylation at Lys-112 and Lys-215 by KAT8 prevents inhibitory binding to SIRT1 and increases its deacetylase activity. Genotoxic stress induces its sumoylation and sumoylation promotes the SIRT1-CCAR2 interaction which in turn inhibits SIRT1-mediated deacetylation of p53/TP53. Sumoylation leads to transcriptional activation of p53/TP53 by sequestering SIRT1 from p53/TP53. Desumoylated by SENP1. Mice mimic a fasted state and therefore, display an increased production of glucose. Display elevated levels of PCK1 and are glucose-intolerant in both a normal and a high-fat diet (PubMed:24415752). Mice develop more tumors including lymphomas, liver tumors, lung tumors (PubMed:25732823). Truncated N-terminus. Truncated N-terminus.