Abstract
PCNA is a homotrimeric ring with important roles in DNA replication and repair. PCNA is loaded and unloaded by the RFC complex, which is composed of five subunits (Rfc1-5). Three additional complexes that share with RFC the small subunits (Rfc2-5) and contain alternative large subunits were found in yeast and other eukaryotes. We have recently reported that one of these, the Elg1-RFC complex, interacts with SUMOylated PCNA and may play a role in its unloading during DNA repair. Here we report that a yeast-two-hybrid screen with the N terminus of Elg1(which interacts with SUMOylated PCNA) uncovered interactions with proteins that belong to the SUMO pathway, including Slx5 and Slx8, which form an E3 ubiquitin ligase that ubiquitinates SUMOylated proteins. Mutations in SLX5 result in a genomic instability phenotype similar to that of elg1 mutants. The physical interaction between the N terminus of Elg1 and Slx5 is mediated by poly-SUMO chains but not by PCNA modifications, and requires Siz2, but not Siz1, activity. Thus our results highlight the many important roles played by Elg1, some of which are PCNA-dependent and some PCNA-independent.
Original language | English |
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Pages (from-to) | 2894-2903 |
Number of pages | 10 |
Journal | Cell Cycle |
Volume | 10 |
Issue number | 17 |
DOIs | |
State | Published - 1 Sep 2011 |
Externally published | Yes |
Bibliographical note
Funding Information:stringent conditions). Plasmids were isolated from positive clones We thank Stefan Jentsch, Helle Ulrich, Jurgen Dohmen, Steven and re-transformed to validate results. J. Brill, Mark Hochstrasser, Daniel Durocher, Erica S. Johnson, DNA damage sensitivity. To test chronic exposure to DNA Philip Hieter and Peter Burgers for reagents. We thank all the damaging agents, serial 10-fold dilutions of logarithmic yeast members of the Kupiec lab for advice and support. M.K. was sup-cells were spotted on fresh SD-complete plates with or without ported by grants from the Israel Cancer Research Fund and the MMS (Sigma), and incubated at 30°C for three days. Israel Cancer Association. Recombination/Mutation assays. The rate of recombination was measured in derivatives of strain MK166, as described in reference 50. This strain allows one to measure forward mutation at CAN1 (white Canavanine-resistant colonies), recombination
Keywords
- PCNA
- STUbL
- SUMO
- Yeast
- elg1
- slx5-slx8