title: The Replisome-Coupled E3 Ubiquitin Ligase Rtt101Mms22 Counteracts Mrc1 Function to Tolerate Genotoxic Stress.
abstract: Faithful DNA replication and repair requires the activity of cullin 4-based E3 ubiquitin ligases (CRL4), but the underlying mechanisms remain poorly understood. The budding yeast Cul4 homologue, Rtt101, in complex with the linker Mms1 and the putative substrate adaptor Mms22 promotes progression of replication forks through damaged DNA. Here we characterized the interactome of Mms22 and found that the Rtt101(Mms22) ligase associates with the replisome progression complex during S-phase via the amino-terminal WD40 domain of Ctf4. Moreover, genetic screening for suppressors of the genotoxic sensitivity of rtt101Δ cells identified a cluster of replication proteins, among them a component of the fork protection complex, Mrc1. In contrast to rtt101Δ and mms22Δ cells, mrc1Δ rtt101Δ and mrc1Δ mms22Δ double mutants complete DNA replication upon replication stress by facilitating the repair/restart of stalled replication forks using a Rad52-dependent mechanism. Our results suggest that the Rtt101(Mms22) E3 ligase does not induce Mrc1 degradation, but specifically counteracts Mrc1's replicative function, possibly by modulating its interaction with the CMG (Cdc45-MCM-GINS) complex at stalled forks.
authors: Institute of Biochemistry, Department of Biology, ETH Zurich, Zürich, Switzerland.
authors: Raymond
authors: R
authors: Buser
authors: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany.
authors: Vanessa
authors: V
authors: Kellner
authors: Institute of Biochemistry, Department of Biology, ETH Zurich, Zürich, Switzerland.
authors: Andre
authors: A
authors: Melnik
authors: Institute of Biochemistry, Department of Biology, ETH Zurich, Zürich, Switzerland.
authors: Caroline
authors: C
authors: Wilson-Zbinden
authors: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany.
authors: René
authors: R
authors: Schellhaas
authors: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany.
authors: Lisa
authors: L
authors: Kastner
authors: Institute of Biochemistry, Department of Biology, ETH Zurich, Zürich, Switzerland.
authors: Wojciech
authors: W
authors: Piwko
authors: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany.
authors: Martina
authors: M
authors: Dees
authors: Institute of Biochemistry, Department of Biology, ETH Zurich, Zürich, Switzerland.
authors: Paola
authors: P
authors: Picotti
authors: MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom.
authors: Marija
authors: M
authors: Maric
authors: MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom.
authors: Karim
authors: K
authors: Labib
authors: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany.
authors: Brian
authors: B
authors: Luke
authors: Institute of Biochemistry, Department of Biology, ETH Zurich, Zürich, Switzerland.
authors: Matthias
authors: M
authors: Peter
mesh_terms: D000222:Adaptation, Physiological; D018797:Cell Cycle Proteins / Q000378:metabolism*; D044842:Cullin Proteins / Q000737:chemistry / Q000378:metabolism*; D004249:DNA Damage; D004261:DNA Replication / Q000235:genetics; D004259:DNA-Directed DNA Polymerase / Q000235:genetics* / Q000378:metabolism; D005800:Genes, Fungal; D059765:Homologous Recombination / Q000235:genetics; D009097:Multienzyme Complexes / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D000099272:Replisomes
chemical_list: D018797:Cell Cycle Proteins; D044842:Cullin Proteins; D004259:DNA-Directed DNA Polymerase; D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D000099272:Replisomes; C441579:MRC1 protein, S cerevisiae; C497133:Mms22 protein, S cerevisiae; C476451:RTT101 protein, S cerevisiae