Rad4TopBP1, a Scaffold Protein, Plays Separate Roles in DNA Damage and Replication Checkpoints and DNA Replication
- 1 August 2006
- journal article
- Published by American Society for Cell Biology (ASCB) in Molecular Biology of the Cell
- Vol. 17 (8), 3456-3468
- https://doi.org/10.1091/mbc.e06-01-0056
Abstract
Rad4TopBP1, a BRCT domain protein, is required for both DNA replication and checkpoint responses. Little is known about how the multiple roles of Rad4TopBP1are coordinated in maintaining genome integrity. We show here that Rad4TopBP1of fission yeast physically interacts with the checkpoint sensor proteins, the replicative DNA polymerases, and a WD-repeat protein, Crb3. We identified four novel mutants to investigate how Rad4TopBP1could have multiple roles in maintaining genomic integrity. A novel mutation in the third BRCT domain of rad4+TopBP1abolishes DNA damage checkpoint response, but not DNA replication, replication checkpoint, and cell cycle progression. This mutant protein is able to associate with all three replicative polymerases and checkpoint proteins Rad3ATR-Rad26ATRIP, Hus1, Rad9, and Rad17 but has a compromised association with Crb3. Furthermore, the damaged-induced Rad9 phosphorylation is significantly reduced in this rad4TopBP1mutant. Genetic and biochemical analyses suggest that Crb3 has a role in the maintenance of DNA damage checkpoint and influences the Rad4TopBP1damage checkpoint function. Taken together, our data suggest that Rad4TopBP1provides a scaffold to a large complex containing checkpoint and replication proteins thereby separately enforcing checkpoint responses to DNA damage and replication perturbations during the cell cycle.Keywords
This publication has 38 references indexed in Scilit:
- Identification and functional analysis of TopBP1 and its homologsDNA Repair, 2005
- The Fission Yeast Crb2/Chk1 Pathway Coordinates the DNA Damage and Spindle Checkpoint in Response to Replication Stress Induced by Topoisomerase I InhibitorMolecular and Cellular Biology, 2005
- DNA polymerases α, δ, and ɛ localize and function together at replication forks inSaccharomyces cerevisiaeGenes to Cells, 2005
- G2 damage checkpoints: what is the turn-on?Journal of Cell Science, 2005
- Choreography of the DNA Damage Response: Spatiotemporal Relationships among Checkpoint and Repair ProteinsCell, 2004
- Chk1 activation requires Rad9 S/TQ-site phosphorylation to promote association with C-terminal BRCT domains of Rad4TOPBP1Genes & Development, 2004
- Dpb11 Controls the Association between DNA Polymerases α and ɛ and the Autonomously Replicating Sequence Region of Budding YeastMolecular and Cellular Biology, 2000
- Fission yeast cut5+, required for S phase onset and M phase restraint, is identical to the radiation-damage repair gene rad4+Cell, 1993
- Thiamine-repressible expression vectors pREP and pRIP for fission yeastGene, 1993
- [56] Molecular genetic analysis of fission yeast Schizosaccharomyces pombeMethods in Enzymology, 1991