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Constitutive phosphorylation of MDC1 physically links the MRE11–RAD50–NBS1 complex to damaged chromatin

The MRE11–RAD50–Nijmegen breakage syndrome 1 (NBS1 [MRN]) complex accumulates at sites of DNA double-strand breaks (DSBs) in microscopically discernible nuclear foci. Focus formation by the MRN complex is dependent on MDC1, a large nuclear protein that directly interacts with phosphorylated H2AX. In...

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Autores principales: Spycher, Christoph, Miller, Edward S., Townsend, Kelly, Pavic, Lucijana, Morrice, Nicholas A., Janscak, Pavel, Stewart, Grant S., Stucki, Manuel
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2315671/
https://www.ncbi.nlm.nih.gov/pubmed/18411308
http://dx.doi.org/10.1083/jcb.200709008
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author Spycher, Christoph
Miller, Edward S.
Townsend, Kelly
Pavic, Lucijana
Morrice, Nicholas A.
Janscak, Pavel
Stewart, Grant S.
Stucki, Manuel
author_facet Spycher, Christoph
Miller, Edward S.
Townsend, Kelly
Pavic, Lucijana
Morrice, Nicholas A.
Janscak, Pavel
Stewart, Grant S.
Stucki, Manuel
author_sort Spycher, Christoph
collection PubMed
description The MRE11–RAD50–Nijmegen breakage syndrome 1 (NBS1 [MRN]) complex accumulates at sites of DNA double-strand breaks (DSBs) in microscopically discernible nuclear foci. Focus formation by the MRN complex is dependent on MDC1, a large nuclear protein that directly interacts with phosphorylated H2AX. In this study, we identified a region in MDC1 that is essential for the focal accumulation of the MRN complex at sites of DNA damage. This region contains multiple conserved acidic sequence motifs that are constitutively phosphorylated in vivo. We show that these motifs are efficiently phosphorylated by caseine kinase 2 (CK2) in vitro and directly interact with the N-terminal forkhead-associated domain of NBS1 in a phosphorylation-dependent manner. Mutation of these conserved motifs in MDC1 or depletion of CK2 by small interfering RNA disrupts the interaction between MDC1 and NBS1 and abrogates accumulation of the MRN complex at sites of DNA DSBs in vivo. Thus, our data reveal the mechanism by which MDC1 physically couples the MRN complex to damaged chromatin.
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spelling pubmed-23156712008-10-21 Constitutive phosphorylation of MDC1 physically links the MRE11–RAD50–NBS1 complex to damaged chromatin Spycher, Christoph Miller, Edward S. Townsend, Kelly Pavic, Lucijana Morrice, Nicholas A. Janscak, Pavel Stewart, Grant S. Stucki, Manuel J Cell Biol Research Articles The MRE11–RAD50–Nijmegen breakage syndrome 1 (NBS1 [MRN]) complex accumulates at sites of DNA double-strand breaks (DSBs) in microscopically discernible nuclear foci. Focus formation by the MRN complex is dependent on MDC1, a large nuclear protein that directly interacts with phosphorylated H2AX. In this study, we identified a region in MDC1 that is essential for the focal accumulation of the MRN complex at sites of DNA damage. This region contains multiple conserved acidic sequence motifs that are constitutively phosphorylated in vivo. We show that these motifs are efficiently phosphorylated by caseine kinase 2 (CK2) in vitro and directly interact with the N-terminal forkhead-associated domain of NBS1 in a phosphorylation-dependent manner. Mutation of these conserved motifs in MDC1 or depletion of CK2 by small interfering RNA disrupts the interaction between MDC1 and NBS1 and abrogates accumulation of the MRN complex at sites of DNA DSBs in vivo. Thus, our data reveal the mechanism by which MDC1 physically couples the MRN complex to damaged chromatin. The Rockefeller University Press 2008-04-21 /pmc/articles/PMC2315671/ /pubmed/18411308 http://dx.doi.org/10.1083/jcb.200709008 Text en Copyright © 2008, The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Research Articles
Spycher, Christoph
Miller, Edward S.
Townsend, Kelly
Pavic, Lucijana
Morrice, Nicholas A.
Janscak, Pavel
Stewart, Grant S.
Stucki, Manuel
Constitutive phosphorylation of MDC1 physically links the MRE11–RAD50–NBS1 complex to damaged chromatin
title Constitutive phosphorylation of MDC1 physically links the MRE11–RAD50–NBS1 complex to damaged chromatin
title_full Constitutive phosphorylation of MDC1 physically links the MRE11–RAD50–NBS1 complex to damaged chromatin
title_fullStr Constitutive phosphorylation of MDC1 physically links the MRE11–RAD50–NBS1 complex to damaged chromatin
title_full_unstemmed Constitutive phosphorylation of MDC1 physically links the MRE11–RAD50–NBS1 complex to damaged chromatin
title_short Constitutive phosphorylation of MDC1 physically links the MRE11–RAD50–NBS1 complex to damaged chromatin
title_sort constitutive phosphorylation of mdc1 physically links the mre11–rad50–nbs1 complex to damaged chromatin
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2315671/
https://www.ncbi.nlm.nih.gov/pubmed/18411308
http://dx.doi.org/10.1083/jcb.200709008
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