TY - JOUR
T1 - Homologous recombination–deficient mutation cluster in tumor suppressor RAD51C identified by comprehensive analysis of cancer variants
AU - Prakash, Rohit
AU - Rawal, Yashpal
AU - Sullivan, Meghan R.
AU - Grundy, McKenzie K.
AU - Bret, Hélène
AU - Mihalevic, Michael J.
AU - Rein, Hayley L.
AU - Baird, Jared M.
AU - Darrah, Kristie
AU - Zhang, Fang
AU - Wang, Raymond
AU - Traina, Tiffany A.
AU - Radke, Marc R.
AU - Kaufmann, Scott H.
AU - Swisher, Elizabeth M.
AU - Guérois, Raphaël
AU - Modesti, Mauro
AU - Sung, Patrick
AU - Jasin, Maria
AU - Bernstein, Kara A.
N1 - Publisher Copyright:
Copyright © 2022 the Author(s). Published by PNAS.
PY - 2022/9/20
Y1 - 2022/9/20
N2 - Mutations in homologous recombination (HR) genes, including BRCA1, BRCA2, and the RAD51 paralog RAD51C, predispose to tumorigenesis and sensitize cancers to DNA-damaging agents and poly(ADP ribose) polymerase inhibitors. However, ∼800 missense variants of unknown significance have been identified for RAD51C alone, impairing cancer risk assessment and therapeutic strategies. Here, we interrogated >50 RAD51C missense variants, finding that mutations in residues conserved with RAD51 strongly predicted HR deficiency and disrupted interactions with other RAD51 paralogs. A cluster of mutations was identified in and around the Walker A box that led to impairments in HR, interactions with three other RAD51 paralogs, binding to single-stranded DNA, and ATP hydrolysis. We generated structural models of the two RAD51 paralog complexes containing RAD51C, RAD51B-RAD51C-RAD51D-XRCC2 and RAD51C-XRCC3. Together with our functional and biochemical analyses, the structural models predict ATP binding at the interface of RAD51C interactions with other RAD51 paralogs, similar to interactions between monomers in RAD51 filaments, and explain the failure of RAD51C variants in binding multiple paralogs. Ovarian cancer patients with variants in this cluster showed exceptionally long survival, which may be relevant to the reversion potential of the variants. This comprehensive analysis provides a framework for RAD51C variant classification. Importantly, it also provides insight into the functioning of the RAD51 paralog complexes.
AB - Mutations in homologous recombination (HR) genes, including BRCA1, BRCA2, and the RAD51 paralog RAD51C, predispose to tumorigenesis and sensitize cancers to DNA-damaging agents and poly(ADP ribose) polymerase inhibitors. However, ∼800 missense variants of unknown significance have been identified for RAD51C alone, impairing cancer risk assessment and therapeutic strategies. Here, we interrogated >50 RAD51C missense variants, finding that mutations in residues conserved with RAD51 strongly predicted HR deficiency and disrupted interactions with other RAD51 paralogs. A cluster of mutations was identified in and around the Walker A box that led to impairments in HR, interactions with three other RAD51 paralogs, binding to single-stranded DNA, and ATP hydrolysis. We generated structural models of the two RAD51 paralog complexes containing RAD51C, RAD51B-RAD51C-RAD51D-XRCC2 and RAD51C-XRCC3. Together with our functional and biochemical analyses, the structural models predict ATP binding at the interface of RAD51C interactions with other RAD51 paralogs, similar to interactions between monomers in RAD51 filaments, and explain the failure of RAD51C variants in binding multiple paralogs. Ovarian cancer patients with variants in this cluster showed exceptionally long survival, which may be relevant to the reversion potential of the variants. This comprehensive analysis provides a framework for RAD51C variant classification. Importantly, it also provides insight into the functioning of the RAD51 paralog complexes.
KW - DNA repair
KW - Homologous recombination
KW - RAD51 paralog
KW - RAD51C
KW - Variants of unknown significance
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U2 - 10.1073/pnas.2202727119
DO - 10.1073/pnas.2202727119
M3 - Article
C2 - 36099300
AN - SCOPUS:85138444692
SN - 0027-8424
VL - 119
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 38
M1 - e2202727119
ER -