| Autor: |
Nieminuszczy J; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK., Martin PR; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK., Broderick R; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK., Krwawicz J; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK., Kanellou A; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK., Mocanu C; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK., Bousgouni V; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK., Smith C; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK., Wen KK; Department of Pediatrics, Division of Pediatric Hematology-Oncology, PennState College of Medicine, PennState Health Children's Hospital, Hershey, Pennsylvania 17033, USA., Woodward BL; Genome Stability and Human Disease Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK., Bakal C; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK., Shackley F; Paediatric Immunology, Allergy and Infectious Diseases, Sheffield Children's Hospital NHS Foundation Trust, Sheffield, UK., Aguilera A; Centro Andaluz de Biologia Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain., Stewart GS; Genome Stability and Human Disease Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK., Vyas YM; Department of Pediatrics, Division of Pediatric Hematology-Oncology, PennState College of Medicine, PennState Health Children's Hospital, Hershey, Pennsylvania 17033, USA., Niedzwiedz W; Cancer Biology, The Institute of Cancer Research, London, SW3 6JB, UK. |
| Abstrakt: |
Accurate genome replication is essential for all life and a key mechanism of disease prevention, underpinned by the ability of cells to respond to replicative stress (RS) and protect replication forks. These responses rely on the formation of Replication Protein A (RPA)-single stranded (ss) DNA complexes, yet this process remains largely uncharacterized. Here we establish that actin nucleation-promoting factors (NPFs) associate with replication forks, promote efficient DNA replication and facilitate association of RPA with ssDNA at sites of RS. Accordingly, their loss leads to deprotection of ssDNA at perturbed forks, impaired ATR activation, global replication defects and fork collapse. Supplying an excess of RPA restores RPA foci formation and fork protection, suggesting a chaperoning role for actin nucleators (ANs) (i.e., Arp2/3, DIAPH1) and NPFs (i.e, WASp, N-WASp) in regulating RPA availability upon RS. We also discover that β-actin interacts with RPA directly in vitro , and in vivo a hyper-depolymerizing β-actin mutant displays a heightened association with RPA and the same dysfunctional replication phenotypes as loss of ANs/NPFs, which contrasts with the phenotype of a hyper-polymerizing β-actin mutant. Thus, we identify components of actin polymerization pathways that are essential for preventing ectopic nucleolytic degradation of perturbed forks by modulating RPA activity. |
