ISWIkomplekser

ISWI (Imitation Switch Inhibitor) complexes are crucial molecular machines involved in chromatin remodeling. They are part of the ISWI family of ATP-dependent chromatin remodelers. These complexes play a significant role in regulating gene expression by altering the structure of nucleosomes, the basic units of chromatin. By moving, ejecting, or restructuring nucleosomes, ISWI complexes can either expose or hide DNA sequences, thereby controlling access for transcription factors and other regulatory proteins.

The core of ISWI complexes typically consists of the ISWI protein, which possesses the ATPase and DNA-binding domains responsible for chromatin remodeling activity, and a variety of accessory subunits. These subunits can vary depending on the specific ISWI complex and its cellular function, influencing substrate specificity and catalytic activity. Different ISWI complexes have been identified in various organisms, each with distinct roles in processes such as DNA replication, repair, and development.

The mechanism of action involves the hydrolysis of ATP by the ISWI ATPase domain, which powers conformational changes within the complex. These changes facilitate the physical manipulation of nucleosomes. For instance, ISWI complexes can slide nucleosomes along the DNA or partially eject them. This dynamic remodeling of chromatin is essential for maintaining genome stability and orchestrating complex gene regulatory networks. Dysregulation of ISWI complex function has been linked to various diseases, including cancer, highlighting their importance in cellular homeostasis. Research into ISWI complexes continues to unravel their intricate roles in epigenetics and gene regulation.