The Cac1 subunit of histone chaperone CAF-1 organizes CAF-1-H3/H4 architecture and tetramerizes histones.
Liu, W.H., Roemer, S.C., Zhou, Y., Shen, Z.J., Dennehey, B.K., Balsbaugh, J.L., Liddle, J.C., Nemkov, T., Ahn, N.G., Hansen, K.C., Tyler, J.K., Churchill, M.E.(2016) Elife 5
- PubMed: 27690308 
- DOI: https://doi.org/10.7554/eLife.18023
- Primary Citation of Related Structures:  
5JBM - PubMed Abstract: 
The histone chaperone Chromatin Assembly Factor 1 (CAF-1) deposits tetrameric (H3/H4) 2 histones onto newly-synthesized DNA during DNA replication. To understand the mechanism of the tri-subunit CAF-1 complex in this process, we investigated the protein-protein interactions within the CAF-1-H3/H4 architecture using biophysical and biochemical approaches. Hydrogen/deuterium exchange and chemical cross-linking coupled to mass spectrometry reveal interactions that are essential for CAF-1 function in budding yeast, and importantly indicate that the Cac1 subunit functions as a scaffold within the CAF-1-H3/H4 complex. Cac1 alone not only binds H3/H4 with high affinity, but also promotes histone tetramerization independent of the other subunits. Moreover, we identify a minimal region in the C-terminus of Cac1, including the structured winged helix domain and glutamate/aspartate-rich domain, which is sufficient to induce (H3/H4) 2 tetramerization. These findings reveal a key role of Cac1 in histone tetramerization, providing a new model for CAF-1-H3/H4 architecture and function during eukaryotic replication.
Organizational Affiliation: 
Department of Pharmacology, University of Colorado School of Medicine, Aurora, United States.