Ubiquitylation of the 9-1-1 checkpoint clamp is independent of rad6-rad18 and DNA damage.
A recent report proposed a function of the ubiquitin conjugation factors Rad6 and Rad18 comparable to the bacterial SOS response, controlling damage-induced transcriptional activation and contributing to checkpoint signaling. The relevant ubiquitylation target was identified as budding yeast Rad17, a subunit of the PCNA-like 9-1-1 checkpoint clamp. We report here ... that in fact all three subunits of the 9-1-1 complex are ubiquitylated. However, in contrast to previous results, we found modification of Rad17 to be independent of DNA damage, the Rad6-Rad18 complex, the putative acceptor site (lysine 197), and loading of the complex onto DNA. Consistently, we were unable to observe enhanced damage sensitivity or defects in checkpoint signaling in a rad17(K197R) mutant. Instead, our findings suggest that ubiquitylation of the 9-1-1 complex may be a background reaction that in some cases can mediate proteasomal degradation.
Mesh Terms:
Amino Acid Sequence, Cell Cycle Proteins, DNA Damage, DNA-Binding Proteins, Humans, Molecular Sequence Data, Nuclear Proteins, Proteasome Endopeptidase Complex, Saccharomyces cerevisiae Proteins, Sequence Alignment, Ubiquitin-Conjugating Enzymes, Ubiquitination
Amino Acid Sequence, Cell Cycle Proteins, DNA Damage, DNA-Binding Proteins, Humans, Molecular Sequence Data, Nuclear Proteins, Proteasome Endopeptidase Complex, Saccharomyces cerevisiae Proteins, Sequence Alignment, Ubiquitin-Conjugating Enzymes, Ubiquitination
Cell
Date: Jun. 11, 2010
PubMed ID: 20550940
View in: Pubmed Google Scholar
Download Curated Data For This Publication
102346
Switch View:
- Interactions 5
- PTM Genes 4