SMARCAD1 is an ATP-dependent chr4 remodeling protein that functions as both a nucleosome remodeler and histone chaperone. Structurally, it belongs to the SNF2 ATPase family and possesses intrinsic ATP-dependent nucleosome-remodeling activity combined with chaperone-like ATP-independent histone deposition capabilities 1. SMARCAD1 exhibits substrate preference for subnucleosomal particles (hexasomes) over canonical nucleosomes, with the FACT complex acting synergistically to enhance its nucleosome remodeling activity 2. Mechanistically, SMARCAD1 regulates DNA double-strand break (DSB) repair by promoting DNA end resection through weakening histone-DNA interactions flanking DSBs 3. It interacts with MSH2-MSH3 to facilitate EXO1 recruitment for long-range resection while inhibiting polymerase theta-mediated end-joining 4. SMARCAD1 also maintains heterochromatin organization post-replication by directing H3K9me3 and histone deacetylation 5. Its activities are regulated by phosphorylation, which modulates nucleosome binding, ATP hydrolysis, and histone exchange 6. Genome-wide, SMARCAD1 associates with architectural proteins including cohesin, laminB, and TFIIIC, suggesting roles in genome organization 7. Clinically, SMARCAD1 mutations cause genetic disorders including adermatoglyphia, Basan syndrome, and Huriez syndrome, underscoring its importance in skin development and barrier function.