Class I and IIa histone deacetylases (Class I and IIa HDACs)

Class I and IIa histone deacetylases (HDACs) are a group of zinc-dependent enzymes that catalyze the removal of acetyl groups from the epsilon-amino groups of lysine residues on histone tails and various non-histone proteins (Seto & Yoshida, 2014, Cold Spring Harb Perspect Biol). Class I HDACs (HDAC1, 2, 3, and 8) are primarily localized in the nucleus and are essential for regulating cell cycle progression and survival (UniProt). Class IIa HDACs (HDAC4, 5, 7, and 9) exhibit tissue-specific expression and shuttle between the nucleus and cytoplasm, often serving as transcriptional co-repressors in muscle, neural, and immune tissues (Falkenberg & Johnstone, 2014, Nat Rev Drug Discov). In many cancers, these enzymes are overexpressed or recruited to tumor suppressor promoters, leading to epigenetic silencing and uncontrolled proliferation (PubMed). Therapeutic intervention typically involves HDAC inhibitors (HDACis) like vorinostat and panobinostat, which bind to the enzyme active site to block deacetylation, thereby inducing apoptosis and cell cycle arrest in malignant cells (StatPearls). Beyond oncology, these targets are being investigated for their roles in neurodegeneration and inflammatory diseases due to their broad impact on gene expression and protein stability (NIH).

Other names

HDAC Class I and IIaLysine deacetylasesKDACsZinc-dependent histone deacetylases

Inhibition of the zinc-dependent catalytic domain of histone deacetylases, which prevents the removal of acetyl groups from lysine residues on histones and non-histone proteins, leading to hyperacetylation and altered gene expression (Seto & Yoshida, 2014; StatPearls).