SETD6 is a protein lysine methyltransferase that regulates diverse cellular processes through substrate-specific monomethylation. The enzyme demonstrates complex biochemical properties, forming oligomeric structures stabilized by S-adenosyl-L-methionine and exhibiting auto-methylation activity at K39 and K179, which enhances its catalytic rate 1. SETD6's primary function involves transcriptional regulation through methylation of key transcription factors. It monomethylates RELA (NF-κB subunit) at Lys-310, leading to NF-κB transcriptional downregulation 1. The enzyme also methylates BRD4 at K99, which is crucial for HPV transcription and selective gene regulation in melanoma cells 23. Additional substrates include TWIST1 (K33), which regulates LINC-PINT expression and epithelial-mesenchymal transition in glioma 4, and E2F1 (K117), establishing a positive feedback loop for SETD6 expression 5. SETD6 exhibits dual transcriptional roles, functioning as both repressor and co-activator depending on context, particularly in estrogen-responsive gene regulation 6. Functionally, SETD6 collaborates with SETD3 in apoptosis regulation and demonstrates significant roles in cancer cell proliferation and survival 76. The enzyme's diverse substrate specificity and regulatory mechanisms highlight its importance in chr16 biology and cellular homeostasis 8.