INO80

INO80 is an evolutionarily conserved ATP-dependent chromatin remodeling complex that modulates nucleosome structure to regulate DNA accessibility. It uses energy from ATP hydrolysis to slide, reposition, or evict nucleosomes and to facilitate exchange of histone variants in coordination with histone chaperones. The catalytic engine of INO80 is the Ino80 ATPase subunit.

INO80 exists as a large multiprotein complex in eukaryotes. It comprises actin-related proteins and several accessory subunits. In yeast, the complex includes Ies factors and Nhp10, while mammalian versions associate with RUVBL1/2 (Pontin/Reptin) and additional Arp and Ies components.

Biological roles of INO80 include transcriptional regulation by remodeling chromatin at promoters and enhancers, participation in the DNA damage response by remodeling chromatin around double-strand breaks, and involvement in replication and chromatin assembly during S phase. The complex acts in concert with histone chaperones to modulate chromatin dynamics and maintain genome stability during cellular processes that require chromatin remodeling.

Regulation and interactions: INO80 is recruited to sites of DNA damage and interacts with histone marks associated with chromatin states; its activity is coordinated with histone chaperones and other remodelers to achieve appropriate remodeling outcomes.

Clinical and research relevance: Given its central role in genome stability and chromatin regulation, INO80 dysfunction can impair cell viability and genome integrity. Aberrant regulation has been linked to cancer biology in some studies, making it a focus of research into chromatin remodeling and genome maintenance.