title: The cytoskeleton protein filamin-A is required for an efficient recombinational DNA double strand break repair.
abstract: The human actin-binding protein filamin-A (also known as ABP-280) cross-links actin into a dynamic three-dimensional structure. It interacts with >45 proteins of diverse functions, serving as the scaffold in various signaling networks. BRCA2 is a protein that regulates RAD51-dependent recombinational repair of DNA double strand breaks (DSB). Proximate to the COOH terminus of the BRCA2 protein, a conserved and DNA binding domain (BRCA2-DBD) interacts with filamin-A and BCCIP. In this study, we sought to test the hypothesis that filamin-A influences homologous recombinational repair of DSB and the maintenance of genomic stability. We used three pairs of cell lines with normal and reduced filamin-A expression, including breast cancer and melanoma cells. We found that lack or reduction of filamin-A sensitizes cells to ionizing radiation, slows the removal of DNA damage-induced gammaH2AX nuclear foci, reduces RAD51 nuclear focus formation and recruitment to chromatin in response to irradiation, and results in a 2-fold reduction of homologous recombinational repair of DSB. Furthermore, filamin-A-deficient cells have increased frequencies of micronucleus formation after irradiation. Our data illustrate the importance of the cytoskeleton structure in supporting the homologous recombinational DNA repair machinery and genome integrity, and further implicate a potential of filamin-A as a marker for prognosis in DNA damage-based cancer therapy.
authors.affiliation: Department of Radiation Oncology, The Cancer Institute of New Jersey, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, New Jersey 08903, USA.
authors.forename: Jingyin
authors.initials: J
authors.lastname: Yue
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.forename: Huimei
authors.initials: H
authors.lastname: Lu
authors.forename: Mark
authors.initials: M
authors.lastname: Brenneman
authors.forename: Feiyue
authors.initials: F
authors.lastname: Fan
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Shen
mesh_terms: D017209:Apoptosis / Q000528:radiation effects; D024682:BRCA2 Protein / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D002843:Chromatin / Q000235:genetics; D002869:Chromosome Aberrations; D003114:Colony-Forming Units Assay; D003285:Contractile Proteins / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects; D004260:DNA Repair / Q000235:genetics*; D064448:Filamins; D005455:Fluorescent Antibody Technique; D042822:Genomic Instability; D006657:Histones / Q000378:metabolism; D006801:Humans; D008545:Melanoma / Q000235:genetics* / Q000473:pathology; D008840:Microfilament Proteins / Q000502:physiology*; D015162:Micronucleus Tests; D051135:Rad51 Recombinase / Q000378:metabolism; D011839:Radiation, Ionizing; D011995:Recombination, Genetic
chemical_list: D024682:BRCA2 Protein; D002843:Chromatin; D003285:Contractile Proteins; D064448:Filamins; C468783:H2AX protein, human; D006657:Histones; D008840:Microfilament Proteins; D051135:Rad51 Recombinase