HD2

Histone deacetylase 2 (HDAC2) is a class I histone deacetylase that removes acetyl groups from histone lysine residues and regulates chromatin structure and transcriptional activity^[1][2]. HDAC2 functions mainly through association with multiprotein transcriptional corepressor complexes, including Sin3, NuRD, CoREST, and N-CoR complexes, which mediate transcriptional repression^[2][3]. Mechanistically, HDAC2-dependent histone deacetylation contributes to epigenetic regulation by altering histone acetylation states and controlling expression of specific gene programs^[1][2]. In disease models, abnormal HDAC2 regulation has been associated with cancer progression, including hepatocellular carcinoma and colorectal cancer models, through effects on tumor-associated transcriptional programs^[4][5]. HDAC2 expression is increased in hepatocellular carcinoma tissues, and HDAC2 supports malignant progression through regulation of mTORC1-related signaling and tumor cell behavior^[4]. Compared with the closely related isoform HDAC1, HDAC2 shares high sequence similarity and participates in overlapping corepressor complexes, but HDAC2 exhibits distinct functional effects in cancer-associated models and differentiation processes^[5][6]. Unlike class II HDAC proteins that can shuttle between cytoplasm and nucleus, HDAC2 is primarily a nuclear class I HDAC involved in chromatin regulation^[1][7]. For experimental applications, HDAC2 function is studied using genetic knockdown, chromatin analysis, enzyme activity assays, and HDAC inhibitor treatment approaches^[5][7]. HDAC2 inhibition increases apoptosis-related responses and alters expression of cell-cycle regulatory genes in cancer cell models, supporting its use as an experimental target for studying epigenetic regulation^[5].