FBH1 Catalyzes Regression of Stalled Replication Forks
Kasper Fugger,
Martin Mistrik,
Kai J. Neelsen,
Qi Yao,
Ralph Zellweger,
Arne Nedergaard Kousholt,
Peter Haahr,
Wai Kit Chu,
Jiri Bartek,
Massimo Lopes,
Ian D. Hickson,
Claus Storgaard Sørensen
Affiliations
Kasper Fugger
Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
Martin Mistrik
Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Hnevotinska 5, 77900 Olomouc, Czech Republic
Kai J. Neelsen
Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
Qi Yao
Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
Ralph Zellweger
Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
Arne Nedergaard Kousholt
Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
Peter Haahr
Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
Wai Kit Chu
Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
Jiri Bartek
Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Hnevotinska 5, 77900 Olomouc, Czech Republic
Massimo Lopes
Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
Ian D. Hickson
Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
Claus Storgaard Sørensen
Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
DNA replication fork perturbation is a major challenge to the maintenance of genome integrity. It has been suggested that processing of stalled forks might involve fork regression, in which the fork reverses and the two nascent DNA strands anneal. Here, we show that FBH1 catalyzes regression of a model replication fork in vitro and promotes fork regression in vivo in response to replication perturbation. Cells respond to fork stalling by activating checkpoint responses requiring signaling through stress-activated protein kinases. Importantly, we show that FBH1, through its helicase activity, is required for early phosphorylation of ATM substrates such as CHK2 and CtIP as well as hyperphosphorylation of RPA. These phosphorylations occur prior to apparent DNA double-strand break formation. Furthermore, FBH1-dependent signaling promotes checkpoint control and preserves genome integrity. We propose a model whereby FBH1 promotes early checkpoint signaling by remodeling of stalled DNA replication forks.
