Recovery from DNA damage-induced G2 arrest requires actin-binding protein filamin-A/actin-binding protein 280.
Filamin-A (filamin-1) is an actin-binding protein involved in the organization of actin networks. Our previous study shows that filamin-A interacts with BRCA2, and lack of filamin-A expression results in increased cellular sensitivity to several DNA damaging agents in melanoma cells (Yuan, Y., and Shen, Z. (2001) J. Biol. Chem. 276, 48318-48324), suggesting a role of filamin-A in DNA damage response. In this report, we demonstrated that deficiency of filamin-A results in an 8-h delay in the recovery from G2 arrest in response to ionizing radiation. However, filamin-A deficiency does not affect the initial activation of the G2/M checkpoint. We also found that filamin-A deficiency results in sustained activation of Chk1 and Chk2 after irradiation. This in turn causes a delay in the dephosphorylation of phospho-Cdc2, which is inhibitory to the G2/M transition. In addition, filamin-A-deficient M2 cells undergo mitotic catastrophe-related nuclear fragmentation after they are released from the G2 arrest. Together, these data suggest a functional role of filamin-A in the recovery from G2 arrest and subsequent mitotic cell death after DNA damage.
Meng
Xiangbing
X
Department of Molecular Genetics and Microbiology, MSC08 4660, 1 University of New Mexico School of Medicine, Albuquerque, New Mexico 87131-0001, USA.
Yuan
Yuan
Y
Maestas
Adrian
A
Shen
Zhiyuan
Z
D024682:BRCA2 Protein / Q000378:metabolism; D015153:Blotting, Western; D002453:Cell Cycle; D016923:Cell Death; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D003285:Contractile Proteins / Q000737:chemistry* / Q000378:metabolism; D004247:DNA / Q000737:chemistry; D004249:DNA Damage; D053938:DNA Fragmentation; D004307:Dose-Response Relationship, Radiation; D064448:Filamins; D005434:Flow Cytometry; D016195:G2 Phase; D005822:Genetic Vectors; D006801:Humans; D008840:Microfilament Proteins / Q000737:chemistry* / Q000378:metabolism; D008938:Mitosis; D015739:Nocodazole / Q000494:pharmacology; D010766:Phosphorylation; D011485:Protein Binding; D011494:Protein Kinases / Q000737:chemistry; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry; D011691:Puromycin / Q000494:pharmacology; D015398:Signal Transduction; D013997:Time Factors
D024682:BRCA2 Protein; D003285:Contractile Proteins; C578661:FLNC protein, human; D064448:Filamins; D008840:Microfilament Proteins; D011691:Puromycin; D004247:DNA; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; C000605867:CHEK1 protein, human; C578634:CHEK2 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases; D015739:Nocodazole