Histone acetyltransferases (HATs), also known as lysine acetyltransferases (KATs), are enzymes that catalyze the transfer of an acetyl group from acetyl-CoA to the ε-amino group of specific lysine residues on histone proteins. Histone acetylation neutralizes the positive charge of lysine, weakening histone–DNA interactions, reducing chromatin compaction, and increasing DNA accessibility to transcription factors, thereby facilitating gene transcription and regulating gene expression.
Key Families and Functions
HATs are classified into several conserved families, including the GNAT (GCN5/PCAF), MYST, and p300/CBP families. These enzymes commonly operate within multi-protein complexes that regulate their catalytic activity, substrate specificity, and chromatin targeting. In addition to histones, HATs acetylate numerous non-histone proteins, including transcription factors such as p53, thereby influencing a wide range of cellular processes including transcriptional regulation, DNA repair, cell cycle progression, and apoptosis.
Research Applications and Clinical Significance
- Epigenetic regulation: HATs play a central role in controlling chromatin structure and gene expression through reversible histone acetylation.
- Disease relevance: Aberrant HAT activity has been associated with multiple pathological conditions, including cancer, inflammatory diseases, and neurological disorders.
- Drug discovery: HATs have become attractive therapeutic targets, leading to the development of small-molecule inhibitors (e.g., C646, Garcinol, Curcumin), activators (e.g., CTPB, TTK21), and emerging targeted degradation strategies such as PROTACs.
- Biomedical research: Owing to their fundamental role in epigenetic regulation and cellular homeostasis, HATs are extensively studied in molecular biology, translational research, and precision medicine.
