Nuclear ataxia-telangiectasia mutated (ATM) mediates the cellular response to DNA double strand breaks in human neuron-like cells.
The protein kinase ATM (ataxia-telangiectasia mutated) activates the cellular response to double strand breaks (DSBs), a highly cytotoxic DNA lesion. ATM is activated by DSBs and in turn phosphorylates key players in numerous damage response pathways. ATM is missing or inactivated in the autosomal recessive disorder ataxia-telangiectasia (A-T), which is characterized by neuronal degeneration, immunodeficiency, genomic instability, radiation sensitivity, and cancer predisposition. The predominant symptom of A-T is a progressive loss of movement coordination due to ongoing degeneration of the cerebellar cortex and peripheral neuropathy. A major deficiency in understanding A-T is the lack of information on the role of ATM in neurons. It is unclear whether the ATM-mediated DSB response operates in these cells similarly to proliferating cells. Furthermore, ATM was reported to be cytoplasmic in neurons and suggested to function in these cells in capacities other than the DNA damage response. Recently we obtained genetic molecular evidence that the neuronal degeneration in A-T does result from defective DNA damage response. We therefore undertook to investigate this response in a model system of human neuron-like cells (NLCs) obtained by neuronal differentiation in culture. ATM was largely nuclear in NLCs, and their ATM-mediated responses to DSBs were similar to those of proliferating cells. Knocking down ATM did not interfere with neuronal differentiation but abolished ATM-mediated damage responses in NLCs. We concluded that nuclear ATM mediates the DSB response in NLCs similarly to in proliferating cells. Attempts to understand the neurodegeneration in A-T should be directed to investigating the DSB response in the nervous system.
Biton
Sharon
S
The David and Inez Myers Laboratory for Genetic Research, Department of Molecular Genetics and Biochemistry, Tel Aviv University, Tel Aviv 69978, Israel.
Dar
Inbal
I
Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Mittelman
Leonid
L
Interdepartmental Core Facility, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
Pereg
Yaron
Y
The David and Inez Myers Laboratory for Genetic Research, Department of Molecular Genetics and Biochemistry, Tel Aviv University, Tel Aviv 69978, Israel.
Barzilai
Ari
A
Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Shiloh
Yosef
Y
The David and Inez Myers Laboratory for Genetic Research, Department of Molecular Genetics and Biochemistry, Tel Aviv University, Tel Aviv 69978, Israel. Electronic address: yossih@post.tau.ac.il.
D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D049109:Cell Proliferation; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D019636:Neurodegenerative Diseases / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases