Abstract
KAP-1 poses a substantial barrier to DNA double-strand break (DSB) repair within heterochromatin that is alleviated by ATM-dependent KAP-1 phosphorylation (pKAP-1). Here we address the mechanistic consequences of pKAP-1 that promote heterochromatic DSB repair and chromatin relaxation. KAP-1 function involves autoSUMOylation and recruitment of nucleosome deacetylation, methylation and remodeling activities. Although heterochromatin acetylation or methylation changes were not detected, radiation-induced pKAP-1 dispersed the nucleosome remodeler CHD3 from DSBs and triggered concomitant chromatin relaxation; pKAP-1 loss reversed these effects. Depletion or inactivation of CHD3, or ablation of its interaction with KAP-1(SUMO1), bypassed pKAP-1's role in repair. Though KAP-1 SUMOylation was unaffected after irradiation, CHD3 dissociated from KAP-1(SUMO1) in a pKAP-1-dependent manner. We demonstrate that KAP-1(Ser824) phosphorylation generates a motif that directly perturbs interactions between CHD3's SUMO-interacting motif and SUMO1, dispersing CHD3 from heterochromatin DSBs and enabling repair.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Ataxia Telangiectasia Mutated Proteins
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Cell Cycle Proteins / physiology
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DNA Breaks, Double-Stranded*
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DNA Helicases / chemistry
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DNA Helicases / metabolism
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DNA Helicases / physiology*
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DNA Repair*
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DNA-Binding Proteins / physiology
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HEK293 Cells
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HeLa Cells
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Heterochromatin / metabolism
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Histones / metabolism
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Humans
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Mi-2 Nucleosome Remodeling and Deacetylase Complex
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Mice
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Morpholines / pharmacology
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NIH 3T3 Cells
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Nuclear Proteins / chemistry
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Nuclear Proteins / metabolism
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Nuclear Proteins / physiology*
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Nucleosomes / drug effects
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Nucleosomes / metabolism*
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Phosphorylation
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Protein Serine-Threonine Kinases / physiology
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Pyrones / pharmacology
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Repressor Proteins / chemistry
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Repressor Proteins / metabolism
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Repressor Proteins / physiology*
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SUMO-1 Protein / chemistry
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SUMO-1 Protein / metabolism
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SUMO-1 Protein / physiology
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Sumoylation
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Tripartite Motif-Containing Protein 28
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Tumor Suppressor Proteins / physiology
Substances
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2-morpholin-4-yl-6-thianthren-1-yl-pyran-4-one
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Cell Cycle Proteins
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DNA-Binding Proteins
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Heterochromatin
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Histones
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Morpholines
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Nuclear Proteins
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Nucleosomes
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Pyrones
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Repressor Proteins
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SUMO-1 Protein
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SUMO1 protein, human
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Tumor Suppressor Proteins
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TRIM28 protein, human
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Trim28 protein, mouse
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Tripartite Motif-Containing Protein 28
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ATM protein, human
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Ataxia Telangiectasia Mutated Proteins
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Atm protein, mouse
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Protein Serine-Threonine Kinases
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Mi-2 Nucleosome Remodeling and Deacetylase Complex
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DNA Helicases
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CHD3 protein, human