Work

Mechanism of Proliferating Cell Nuclear Antigen Clamp Opening by Replication Factor C

Year: 2006

Type: article

Abstract: The eukaryotic replication factor C (RFC) clamp loader is an AAA+ spiral-shaped heteropentamer that opens and closes the circular proliferating cell nuclear antigen (PCNA) clamp processivity factor on DNA. In this study, we examined the roles of individual RFC subunits in opening the PCNA clamp. Interestingly, Rfc1, which occupies the position analogous to the delta clamp-opening subunit in the Escherichia coli clamp loader, is not required to open PCNA. The Rfc5 subunit is required to open PCNA. Consistent with this result, Rfc2.3.4.5 and Rfc2.5 subassemblies are capable of opening and unloading PCNA from circular DNA. Rfc5 is positioned opposite the PCNA interface from Rfc1, and therefore, its action with Rfc2 in opening PCNA indicates that PCNA is opened from the opposite side of the interface that the E. coli delta wrench acts upon. This marks a significant departure in the mechanism of eukaryotic and prokaryotic clamp loaders. Interestingly, the Rad.RFC DNA damage checkpoint clamp loader unloads PCNA clamps from DNA. We propose that Rad.RFC may clear PCNA from DNA to facilitate shutdown of replication in the face of DNA damage.

Source: Journal of Biological Chemistry

DOI: 10.1074/jbc.m601273200

Authors: Nina Y. Yao, Aaron Johnson, Greg D. Bowman, John Kuriyan, Mike O'Donnell

Institutions: Rockefeller University, Lawrence Berkeley National Laboratory, Howard Hughes Medical Institute, University of California, Berkeley

Language: English

Topic: DNA Repair Mechanisms

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $3,430

Funders: National Institutes of Health, National Institute of General Medical Sciences