title: Genome Protection by the 9-1-1 Complex Subunit HUS1 Requires Clamp Formation, DNA Contacts, and ATR Signaling-independent Effector Functions.
abstract: The RAD9A-HUS1-RAD1 (9-1-1) complex is a heterotrimeric clamp that promotes checkpoint signaling and repair at DNA damage sites. In this study, we elucidated HUS1 functional residues that drive clamp assembly, DNA interactions, and downstream effector functions. First, we mapped a HUS1-RAD9A interface residue that was critical for 9-1-1 assembly and DNA loading. Next, we identified multiple positively charged residues in the inner ring of HUS1 that were crucial for genotoxin-induced 9-1-1 chromatin localization and ATR signaling. Finally, we found two hydrophobic pockets on the HUS1 outer surface that were important for cell survival after DNA damage. Interestingly, these pockets were not required for 9-1-1 chromatin localization or ATR-mediated CHK1 activation but were necessary for interactions between HUS1 and its binding partner MYH, suggesting that they serve as interaction domains for the recruitment and coordination of downstream effectors at damage sites. Together, these results indicate that, once properly loaded onto damaged DNA, the 9-1-1 complex executes multiple, separable functions that promote genome maintenance.
authors.affiliation: From the Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853 and.
authors.forename: Pei Xin
authors.initials: PX
authors.lastname: Lim
authors.affiliation: From the Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853 and.
authors.forename: Darshil R
authors.initials: DR
authors.lastname: Patel
authors.affiliation: From the Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853 and.
authors.forename: Kelsey E
authors.initials: KE
authors.lastname: Poisson
authors.affiliation: From the Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853 and.
authors.forename: Manpreet
authors.initials: M
authors.lastname: Basuita
authors.affiliation: From the Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853 and.
authors.forename: Charlton
authors.initials: C
authors.lastname: Tsai
authors.affiliation: From the Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853 and.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Lyndaker
authors.affiliation: the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors.forename: Bor-Jang
authors.initials: BJ
authors.lastname: Hwang
authors.affiliation: the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors.forename: A-Lien
authors.initials: AL
authors.lastname: Lu
authors.affiliation: From the Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853 and rsw26@cornell.edu.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Weiss
mesh_terms: D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism*; D017931:DNA Primers; D015894:Genome, Human; D006801:Humans; D051379:Mice; D011487:Protein Conformation; D015398:Signal Transduction
chemical_list: D018797:Cell Cycle Proteins; D017931:DNA Primers; C549605:HUS1 protein, human; D004247:DNA; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins
keywords: DNA damage, DNA damage response, checkpoint control, proliferating cell nuclear antigen (PCNA), genomic instability, HUS1, 9-1-1 complex