ATP-dependent nucleosome remodeling complexes: enzymes tailored to deal with chromatin.

Chromatin remodeling complexes play a central role in the control of nuclear processes that utilize genomic DNA as a template including transcription, replication, recombination, and repair. Modulation of chromatin structure is mediated by a wide variety of enzymes which can affect nucleosome stability by either disrupting histone-DNA contacts or by covalently modifying histones and/or DNA. Although the biochemical properties of most chromatin-modifying enzymes have been well characterized and links between histone and DNA-modifying enzymes and ATP-dependent chromatin remodeling complexes have been established, the importance of their concerted action has just begun to emerge. As more and more genes are examined, new rules are being established about their transcriptional regulation, and it is becoming clear that diverse mechanisms are used to modify chromatin and either promote or hinder accessibility to DNA and histones. Moreover, the involvement of ATP-dependent chromatin remodelers in transcriptional regulation of cyclin genes and the association of misregulated expression of chromatin remodeling subunits with many cancers highlight the importance of chromatin remodeling complexes in the control of cell growth and proliferation.