Functional activity of the H3.3 histone chaperone complex HIRA requires trimerization of the HIRA subunit

• Published in: Nature communications Vol. 9; no. 1; pp. 3103 - 15
• Main Authors: Ray-Gallet, Dominique, Ricketts, M. Daniel, Sato, Yukari, Gupta, Kushol, Boyarchuk, Ekaterina, Senda, Toshiya, Marmorstein, Ronen, Almouzni, Geneviève
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 06-08-2018; Nature Publishing Group; Nature Portfolio
• Subjects: 13; 14; 631/337/100/1701; 631/337/100/2286; Adaptor Proteins, Signal Transducing - chemistry; Amino acids; Binding Sites; Biochemistry; Biophysics; Cabin1 protein; Cell Cycle Proteins - chemistry; Cell Line, Tumor; Chromatin; Chromatin - chemistry; Crystallography; Crystallography, X-Ray; Databases, Protein; Deoxyribonucleic acid; DNA; DNA - chemistry; DNA biosynthesis; DNA Damage; Gene expression; Green Fluorescent Proteins - chemistry; HeLa Cells; Histone Chaperones - chemistry; Histones - chemistry; Homology; Humanities and Social Sciences; Humans; Kinases; Life Sciences; Medical research; Molecular Chaperones - chemistry; multidisciplinary; Nuclear Proteins - chemistry; Oligomerization; Plasmids; Protein Binding; Protein Conformation; Proteins; Radiation damage; Science; Science (multidisciplinary); Transcription Factors - chemistry; Ultraviolet radiation; Ultraviolet Rays; Nucleosomes; Histone variants
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-05581-y

The HIRA histone chaperone complex deposits the histone variant H3.3 onto chromatin in a DNA synthesis-independent manner. It comprises three identified subunits, HIRA, UBN1 and CABIN1, however the functional oligomerization state of the complex has not been investigated. Here we use biochemical and crystallographic analysis to show that the HIRA subunit forms a stable homotrimer that binds two subunits of CABIN1 in vitro. A HIRA mutant that is defective in homotrimer formation interacts less efficiently with CABIN1, is not enriched at DNA damage sites upon UV irradiation and cannot rescue new H3.3 deposition in HIRA knockout cells. The structural homology with the homotrimeric replisome component Ctf4/AND-1 enables the drawing of parallels and discussion of the functional importance of the homotrimerization state of the HIRA subunit.
The HIRA histone chaperone complex is involved in the deposition of the histone variant H3.3. Here the authors, by using biochemical and crystallographic approaches, report the homotrimerization of the HIRA subunit which is critical for the functional activity of the complex.