Structure of the human RAD17-RFC clamp loader and 9-1-1 checkpoint clamp bound to a dsDNA-ssDNA junction.
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Embargo End Date
ICR Authors
Authors
Day, M
Oliver, AW
Pearl, LH
Oliver, AW
Pearl, LH
Document Type
Journal Article
Date
2022-08-12
Date Accepted
2022-06-27
Abstract
The RAD9-RAD1-HUS1 (9-1-1) clamp forms one half of the DNA damage checkpoint system that signals the presence of substantial regions of single-stranded DNA arising from replication fork collapse or resection of DNA double strand breaks. Loaded at the 5'-recessed end of a dsDNA-ssDNA junction by the RAD17-RFC clamp loader complex, the phosphorylated C-terminal tail of the RAD9 subunit of 9-1-1 engages with the mediator scaffold TOPBP1 which in turn activates the ATR kinase, localised through the interaction of its constitutive partner ATRIP with RPA-coated ssDNA. Using cryogenic electron microscopy (cryoEM) we have determined the structure of a complex of the human RAD17-RFC clamp loader bound to human 9-1-1, engaged with a dsDNA-ssDNA junction. The structure answers the key questions of how RAD17 confers specificity for 9-1-1 over PCNA, and how the clamp loader specifically recognises the recessed 5' DNA end and fixes the orientation of 9-1-1 on the ssDNA.
Citation
Nucleic Acids Research, 2022, 50 (14), pp. 8279 - 8289
Source Title
Nucleic Acids Research
Publisher
OXFORD UNIV PRESS
ISSN
0305-1048
eISSN
1362-4962
1362-4962
1362-4962
Collections
Research Team
Directorate Struct Biol