Endogenous hSNM1B/Apollo interacts with TRF2 and stimulates ATM in response to ionizing radiation

• Published in: DNA repair Vol. 7; no. 8; pp. 1192 - 1201
• Main Authors: Demuth, Ilja, Bradshaw, Paul S., Lindner, Anika, Anders, Marco, Heinrich, Stefanie, Kallenbach, Julia, Schmelz, Karin, Digweed, Martin, Meyn, M. Stephen, Concannon, Patrick
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 02.08.2008; Elsevier
• Subjects: Anemias. Hemoglobinopathies; Apollo; ARTEMIS; Ataxia Telangiectasia Mutated Proteins; ATM; ATM autophosphorylation; Bacteriology; Biological and medical sciences; Blotting, Western; Cell Cycle Proteins - metabolism; Cell Line; DCLRE1B; Diseases of red blood cells; DNA damage response; DNA Repair Enzymes - metabolism; DNA Repair Enzymes - physiology; DNA-Binding Proteins - metabolism; DNA-repair; Fanconi Anemia; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Growth, nutrition, cell differenciation; Hematologic and hematopoietic diseases; hSNM1B; Humans; Medical sciences; Microbiology; Molecular and cellular biology; Molecular genetics; Mutagenesis. Repair; Nuclear foci; Nuclear Proteins - metabolism; Nuclear Proteins - physiology; p53; Phosphorylation; Protein Binding; Protein-Serine-Threonine Kinases - metabolism; pso2; Radiation, Ionizing; RNA, Small Interfering; siRNA; SNM1; SNM1B; Telomere; Telomeric Repeat Binding Protein 2 - metabolism; TRF2; Tumor Suppressor Proteins - metabolism; Yeast two hybrid; DCLRE1B; DNA damage response; Apollo; Fanconi Anemia; ATM autophosphorylation; siRNA; Yeast two hybrid; TRF2; Telomere; DNA-repair; p53; pso2; Nuclear foci; hSNM1B; SNM1B; ARTEMIS; SNM1; ATM; Chromosome fragility; Autophosphorylation; RNA interference; Yeast; hSNM1B,SNM1B,Apollo,DCLRE1B,SNM1,pso2,ARTEMIS,TRF2,Telomere,ATM,ATM autophosphorylation,Fanconi Anemia,DNA-repair,Yeast two hybrid,siRNA,p53,Nuclear foci,DNA damage response; Fanconi anemia; Hybrid; Hemopathy; Genetic disease; Gene silencing; Ionizing radiation; Endogenous; TP53 Gene; DNA; Lesion; Repair; Tumor suppressor gene
• ISSN: 1568-7864; 1568-7856
• DOI: 10.1016/j.dnarep.2008.03.020

Human SNM1B/Apollo is involved in the cellular response to DNA-damage, however, its precise role is unknown. Recent reports have implicated hSNM1B in the protection of telomeres. We have found hSNM1B to interact with TRF2, a protein which functions in telomere protection and in an early response to ionizing radiation. Here we show that endogenous hSNM1B forms foci which colocalize at telomeres with TRF1 and TRF2. However, we observed that additional hSNM1B foci could be induced upon exposure to ionizing radiation (IR). In live-cell-imaging experiments, hSNM1B localized to photo-induced double-strand breaks (DSBs) within 10s post-induction. Further supporting a role for hSNM1B in the early stages of the cellular response to DSBs, we observed that autophosphorylation of ATM, as well as the phosphorylation of ATM target proteins in response to IR, was attenuated in cells depleted of hSNM1B. These observations suggest an important role for hSNM1B in the response to IR damage, a role that may be, in part, upstream of the central player in maintenance of genome integrity, ATM.