KAT7 Protein, Human (Active, sf9, GST)

HBO1 is the catalytic subunit of histone acetyltransferase HBO1 complexes, specifically mediating acetylation of histone H3 at Lys-14 (H3K14ac) to regulate processes such as gene transcription, protein ubiquitination, immune regulation, stem cell pluripotency and self-renewal maintenance, and embryonic development. Some complexes also acetylate histone H4 at Lys-5, Lys-8, and Lys-12 (H4K5ac, H4K8ac, and H4K12ac), regulating DNA replication initiation. The specificity of HBO1 complexes is determined by scaffold subunits: complexes with BRPF scaffolds (BRPF1, BRD1/BRPF2, or BRPF3) direct KAT7/HBO1 toward H3K14ac, while those with JADE scaffolds (JADE1, JADE2, or JADE3) direct KAT7/HBO1 toward histone H4. H3K14ac promotes transcriptional elongation by enhancing RNA polymerase II processivity. HBO1 acts as a key regulator of hematopoiesis by forming a complex with BRD1/BRPF2 to promote erythroid differentiation (by similarity: H3K14ac is also required for T-cell development). KAT7/HBO1-mediated acetylation facilitates DNA replication initiation: H3K14ac activates replication origins, while H4 acetylation (H4K5ac, H4K8ac, H4K12ac) promotes MCM complex loading for DNA replication licensing. HBO1 positively regulates centromeric CENPA assembly by preventing SUV39H1-mediated centromere inactivation. It also participates in nucleotide excision repair: ATR-phosphorylated HBO1 localizes to DNA damage sites, mediating histone acetylation to recruit XPC. Independently of its acetyltransferase activity, HBO1 inhibits NF-kappa-B. In acute myeloid leukemia (AML), HBO1 maintains leukemia stem cells by mediating H3K14ac to sustain high expression of key genes like HOXA9 and HOXA10.