The Cac1 subunit of histone chaperone CAF-1 organizes CAF-1-H3/H4 architecture and tetramerizes histones
Wallace H Liu,
Sarah C Roemer,
Yeyun Zhou,
Zih-Jie Shen,
Briana K Dennehey,
Jeremy L Balsbaugh,
Jennifer C Liddle,
Travis Nemkov,
Natalie G Ahn,
Kirk C Hansen,
Jessica K Tyler,
Mair EA Churchill
Affiliations
Wallace H Liu
Department of Pharmacology, University of Colorado School of Medicine, Aurora, United States
Sarah C Roemer
Department of Pharmacology, University of Colorado School of Medicine, Aurora, United States
Yeyun Zhou
Department of Pharmacology, University of Colorado School of Medicine, Aurora, United States
Zih-Jie Shen
Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, United States
Briana K Dennehey
Department of Epigenetics and Molecular Carcinogenesis, MD Anderson Cancer Center, Houston, United States
Jeremy L Balsbaugh
Department of Chemistry and Biochemistry, University of Colorado, Boulder, Boulder, United States; BioFrontiers Institute, University of Colorado, Boulder, Boulder, United States
Jennifer C Liddle
Department of Chemistry and Biochemistry, University of Colorado, Boulder, Boulder, United States; BioFrontiers Institute, University of Colorado, Boulder, Boulder, United States
Travis Nemkov
Program in Structural Biology and Biochemistry, University of Colorado School of Medicine, Aurora, United States
Natalie G Ahn
Department of Chemistry and Biochemistry, University of Colorado, Boulder, Boulder, United States; BioFrontiers Institute, University of Colorado, Boulder, Boulder, United States
Kirk C Hansen
Program in Structural Biology and Biochemistry, University of Colorado School of Medicine, Aurora, United States
Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, United States; Department of Epigenetics and Molecular Carcinogenesis, MD Anderson Cancer Center, Houston, United States
Department of Pharmacology, University of Colorado School of Medicine, Aurora, United States; Program in Structural Biology and Biochemistry, University of Colorado School of Medicine, Aurora, United States
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.