The Experts below are selected from a list of 22740 Experts worldwide ranked by ideXlab platform
Catherine Dargemont - One of the best experts on this subject based on the ideXlab platform.
-
H2B Ubiquitylation controls the formation of export-competent mRNP.
Molecular cell, 2012Co-Authors: Adeline Vitaliano-prunier, Carole Gwizdek, Anna Babour, Lucas Hérissant, Luciano H. Apponi, Thanasis Margaritis, Frank C.p. Holstege, Anita H. Corbett, Catherine DargemontAbstract:Histone H2B Ubiquitylation is a transcription-dependent modification that not only regulates nucleosome dynamics but also controls the trimethylation of histone H3 on lysine 4 by promoting Ubiquitylation of Swd2, a component of both the histone methyltransferase COMPASS complex and the cleavage and polyadenylation factor(CPF). We show that preventing either H2B Ubiquitylation or H2B-dependent modification of Swd2 results in nuclear accumulation of poly(A) RNA due to a defect in the integrity and stability of APT, a subcomplex of the CPF. Ubiquitin-regulated APT complex dynamics is required for the correct recruitment of the mRNA export receptor Mex67 to nuclear mRNPs. While H2B Ubiquitylation controls the recruitment of the different Mex67 adaptors to mRNPs, the effect of Swd2 Ubiquitylation is restricted to Yra1 and Nab2, which, in turn, controls poly(A) tail length. Modification of H2B thus participates in the crosstalk between cotranscriptional events and assembly of mRNPs linking nuclear processing and mRNA export.
-
Ubiquitylation of the COMPASS component Swd2 links H2B Ubiquitylation to H3K4 trimethylation
Nature cell biology, 2008Co-Authors: Adeline Vitaliano-prunier, Alexandra Menant, Maria Hobeika, Vincent Géli, Carole Gwizdek, Catherine DargemontAbstract:Mono-Ubiquitylation of histone H2B is required for methylation of histone H3K4. Ubiquitylation of H2B in turn promotes Ubiquitylation of Swd2, a component of the SET1/COMPASS methyltransferase. Inhibiting Swd2 Ubiquitylation impairs recruitment of the COMPASS subunit, which is essential for methylation, and results in reduced H3K4 methylation.
-
Ubiquitylation of the COMPASS component Swd2 links H2B Ubiquitylation to H3K4 trimethylation.
Nature Cell Biology, 2008Co-Authors: Adeline Vitaliano-prunier, Alexandra Menant, Maria Hobeika, Vincent Géli, Carole Gwizdek, Catherine DargemontAbstract:Mono-Ubiquitylation of histone H2B correlates with transcriptional activation and is required for di- and trimethylation at Lys 4 on the histone H3 tail (H3K4) by the SET1/COMPASS methyltransferase complex through a poorly characterized trans-tail pathway. Here we show that mono-Ubiquitylation of histone H2B promotes Ubiquitylation at Lys 68 and Lys 69 of Swd2, the essential component of SET1/COMPASS in Saccharomyces cerevisiae. We found that Rad6/Bre1 Ubiquitylation enzymes responsible for H2B Ubiquitylation also participate directly in Swd2 modification. Preventing Swd2 or H2B Ubiquitylation did not affect Set1 stability, interaction of Swd2 with Set1 or the ability of Swd2 to interact with chromatin. However, we found that mutation of Lys 68 and Lys 69 of Swd2 markedly reduced trimethylation, and to a lesser extent dimethylation, of H3K4 at the 5'-end of transcribing genes without affecting monomethylation. This effect results from the ability of Swd2 Ubiquitylation to control recruitment of Spp1, a COMPASS subunit necessary for trimethylation. Our results further indicate that Swd2 is a major H3-binding component of COMPASS. Swd2 thus represents a key factor that mediates crosstalk between H2B Ubiquitylation and H3K4 trimethylation on chromatin.
Chunaram Choudhary - One of the best experts on this subject based on the ideXlab platform.
-
Histone H1 couples initiation and amplification of ubiquitin signalling after DNA damage
Nature, 2015Co-Authors: Tina Thorslund, Takeo Narita, Titia K. Sixma, Anita Ripplinger, Saskia Hoffmann, Thomas Wild, Michael Uckelmann, Bine H. Villumsen, Chunaram Choudhary, Simon Bekker-jensenAbstract:DNA double-strand breaks (DSBs) are highly cytotoxic DNA lesions that trigger non-proteolytic Ubiquitylation of adjacent chromatin areas to generate binding sites for DNA repair factors. This depends on the sequential actions of the E3 ubiquitin ligases RNF8 and RNF168 (refs 1-6), and UBC13 (also known as UBE2N), an E2 ubiquitin-conjugating enzyme that specifically generates K63-linked ubiquitin chains. Whereas RNF168 is known to catalyse Ubiquitylation of H2A-type histones, leading to the recruitment of repair factors such as 53BP1 (refs 8-10), the critical substrates of RNF8 and K63-linked Ubiquitylation remain elusive. Here we elucidate how RNF8 and UBC13 promote recruitment of RNF168 and downstream factors to DSB sites in human cells. We establish that UBC13-dependent K63-linked Ubiquitylation at DSB sites is predominantly mediated by RNF8 but not RNF168, and that H1-type linker histones, but not core histones, represent major chromatin-associated targets of this modification. The RNF168 module (UDM1) recognizing RNF8-generated Ubiquitylations is a high-affinity reader of K63-ubiquitylated H1, mechanistically explaining the essential roles of RNF8 and UBC13 in recruiting RNF168 to DSBs. Consistently, reduced expression or chromatin association of linker histones impair accumulation of K63-linked ubiquitin conjugates and repair factors at DSB-flanking chromatin. These results identify histone H1 as a key target of RNF8-UBC13 in DSB signalling and expand the concept of the histone code by showing that posttranslational modifications of linker histones can serve as important marks for recognition by factors involved in genome stability maintenance, and possibly beyond.
-
Convergence of Ubiquitylation and Phosphorylation Signaling in Rapamycin-Treated Yeast Cells
Molecular & cellular proteomics : MCP, 2014Co-Authors: Vytautas Iesmantavicius, Brian T. Weinert, Chunaram ChoudharyAbstract:The target of rapamycin (TOR) kinase senses the availability of nutrients and coordinates cellular growth and proliferation with nutrient abundance. Inhibition of TOR mimics nutrient starvation and leads to the reorganization of many cellular processes, including autophagy, protein translation, and vesicle trafficking. TOR regulates cellular physiology by modulating phosphorylation and Ubiquitylation signaling networks; however, the global scope of such regulation is not fully known. Here, we used a mass-spectrometry-based proteomics approach for the parallel quantification of Ubiquitylation, phosphorylation, and proteome changes in rapamycin-treated yeast cells. Our data constitute a detailed proteomic analysis of rapamycin-treated yeast with 3590 proteins, 8961 phosphorylation sites, and 2299 di-Gly modified lysines (putative Ubiquitylation sites) quantified. The phosphoproteome was extensively modulated by rapamycin treatment, with more than 900 up-regulated sites one hour after rapamycin treatment. Dynamically regulated phosphoproteins were involved in diverse cellular processes, prominently including transcription, membrane organization, vesicle-mediated transport, and autophagy. Several hundred Ubiquitylation sites were increased after rapamycin treatment, and about half as many decreased in abundance. We found that proteome, phosphorylation, and Ubiquitylation changes converged on the Rsp5-ubiquitin ligase, Rsp5 adaptor proteins, and Rsp5 targets. Putative Rsp5 targets were biased for increased Ubiquitylation, suggesting activation of Rsp5 by rapamycin. Rsp5 adaptor proteins, which recruit target proteins for Rsp5-dependent Ubiquitylation, were biased for increased phosphorylation. Furthermore, we found that permeases and transporters, which are often ubiquitylated by Rsp5, were biased for reduced Ubiquitylation and reduced protein abundance. The convergence of multiple proteome-level changes on the Rsp5 system indicates a key role of this pathway in the response to rapamycin treatment. Collectively, these data reveal new insights into the global proteome dynamics in response to rapamycin treatment and provide a first detailed view of the co-regulation of phosphorylation- and Ubiquitylation-dependent signaling networks by this compound.
-
rnf111 arkadia is a sumo targeted ubiquitin ligase that facilitates the dna damage response
Journal of Cell Biology, 2013Co-Authors: Sara L. Poulsen, Chunaram Choudhary, Sebastian A. Wagner, Rebecca K Hansen, Loes Van Cuijk, Gijsbert J Van Belle, Werner Streicher, Mats Wikstrom, Adriaan B Houtsmuller, Jurgen A. MarteijnAbstract:Protein modifications by ubiquitin and small ubiquitin-like modifier (SUMO) play key roles in cellular signaling pathways. SUMO-targeted ubiquitin ligases (STUbLs) directly couple these modifications by selectively recognizing SUMOylated target proteins through SUMO-interacting motifs (SIMs), promoting their K48-linked Ubiquitylation and degradation. Only a single mammalian STUbL, RNF4, has been identified. We show that human RNF111/Arkadia is a new STUbL, which used three adjacent SIMs for specific recognition of poly-SUMO2/3 chains, and used Ubc13–Mms2 as a cognate E2 enzyme to promote nonproteolytic, K63-linked Ubiquitylation of SUMOylated target proteins. We demonstrate that RNF111 promoted Ubiquitylation of SUMOylated XPC (xeroderma pigmentosum C) protein, a central DNA damage recognition factor in nucleotide excision repair (NER) extensively regulated by ultraviolet (UV)-induced SUMOylation and Ubiquitylation. Moreover, we show that RNF111 facilitated NER by regulating the recruitment of XPC to UV-damaged DNA. Our findings establish RNF111 as a new STUbL that directly links nonproteolytic Ubiquitylation and SUMOylation in the DNA damage response.
-
Systems-wide analysis of Ubiquitylation dynamics reveals a key role for PAF15 Ubiquitylation in DNA-damage bypass
Nature Cell Biology, 2012Co-Authors: Lou K. Povlsen, Simon Bekker-jensen, Niels Mailand, Kathrine B Sylvestersen, Jon W Poulsen, Michael L Nielsen, Sebastian A. Wagner, Petra Beli, Sara L. Poulsen, Chunaram ChoudharyAbstract:In a quantitative proteomics approach, Mailand, Choudhary and colleagues characterize ultraviolet-regulated Ubiquitylation sites and identify a role for double mono-Ubiquitylation of PCNA-associated factor PAF15 in bypassing replication-blocking lesions in DNA. Protein Ubiquitylation has emerged as a key regulatory mechanism in DNA-damage signalling and repair pathways. We report a proteome-wide, site-specific survey of Ubiquitylation changes after ultraviolet irradiation, identifying numerous upregulated and downregulated Ubiquitylation sites on known components of DNA-damage signalling, as well as on proteins not previously implicated in this process. Our results uncover a critical role for PCNA-associated factor PAF15 (p15(PAF)/KIAA0101) Ubiquitylation during DNA replication. During unperturbed S phase, chromatin-associated PAF15 is modified by double mono-Ubiquitylation of Lys 15 and 24 templated through PCNA binding. Replication blocks trigger rapid, proteasome-dependent removal of Lys 15/24-ubiquitylated PAF15 from PCNA, facilitating bypass of replication-fork-blocking lesions by allowing recruitment of translesion DNA synthesis polymerase polη to mono-ubiquitylated PCNA at stalled replisomes. Our findings demonstrate widespread involvement of ubiquitin signalling in genotoxic-stress responses and identify a critical function for dynamic PAF15 Ubiquitylation in safeguarding genome integrity when DNA replication is challenged.
-
systems wide analysis of Ubiquitylation dynamics reveals a key role for paf15 Ubiquitylation in dna damage bypass
Nature Cell Biology, 2012Co-Authors: Lou K. Povlsen, Niels Mailand, Simon Bekkerjensen, Kathrine B Sylvestersen, Jon W Poulsen, Michael L Nielsen, Sebastian A. Wagner, Petra Beli, Sara L. Poulsen, Chunaram ChoudharyAbstract:In a quantitative proteomics approach, Mailand, Choudhary and colleagues characterize ultraviolet-regulated Ubiquitylation sites and identify a role for double mono-Ubiquitylation of PCNA-associated factor PAF15 in bypassing replication-blocking lesions in DNA.
Jiri Bartek - One of the best experts on this subject based on the ideXlab platform.
-
jmjd1c demethylates mdc1 to regulate the rnf8 and brca1 mediated chromatin response to dna breaks
Nature Structural & Molecular Biology, 2013Co-Authors: Sugiko Watanabe, Kenji Watanabe, Vyacheslav Akimov, Jirina Bartkova, Blagoy Blagoev, Jiri Lukas, Jiri BartekAbstract:Chromatin Ubiquitylation flanking DNA double-strand breaks (DSBs), mediated by RNF8 and RNF168 ubiquitin ligases, orchestrates a two-branch pathway, recruiting repair factors 53BP1 or the RAP80-BRCA1 complex. We report that human demethylase JMJD1C regulates the RAP80-BRCA1 branch of this DNA-damage response (DDR) pathway. JMJD1C was stabilized by interaction with RNF8, was recruited to DSBs, and was required for local Ubiquitylations and recruitment of RAP80-BRCA1 but not 53BP1. JMJD1C bound to RNF8 and MDC1, and demethylated MDC1 at Lys45, thereby promoting MDC1-RNF8 interaction, RNF8-dependent MDC1 Ubiquitylation and recruitment of RAP80-BRCA1 to polyubiquitylated MDC1. Furthermore, JMJD1C restricted formation of RAD51 repair foci, and JMJD1C depletion caused resistance to ionizing radiation and PARP inhibitors, phenotypes relevant to aberrant loss of JMJD1C in subsets of breast carcinomas. These findings identify JMJD1C as a DDR component, with implications for genome-integrity maintenance, tumorigenesis and cancer treatment.
-
JMJD1C demethylates MDC1 to regulate the RNF8 and BRCA1–mediated chromatin response to DNA breaks
Nature structural & molecular biology, 2013Co-Authors: Sugiko Watanabe, Kenji Watanabe, Vyacheslav Akimov, Jirina Bartkova, Blagoy Blagoev, Jiri Lukas, Jiri BartekAbstract:Chromatin Ubiquitylation flanking DNA double-strand breaks (DSBs), mediated by RNF8 and RNF168 ubiquitin ligases, orchestrates a two-branch pathway, recruiting repair factors 53BP1 or the RAP80-BRCA1 complex. We report that human demethylase JMJD1C regulates the RAP80-BRCA1 branch of this DNA-damage response (DDR) pathway. JMJD1C was stabilized by interaction with RNF8, was recruited to DSBs, and was required for local Ubiquitylations and recruitment of RAP80-BRCA1 but not 53BP1. JMJD1C bound to RNF8 and MDC1, and demethylated MDC1 at Lys45, thereby promoting MDC1-RNF8 interaction, RNF8-dependent MDC1 Ubiquitylation and recruitment of RAP80-BRCA1 to polyubiquitylated MDC1. Furthermore, JMJD1C restricted formation of RAD51 repair foci, and JMJD1C depletion caused resistance to ionizing radiation and PARP inhibitors, phenotypes relevant to aberrant loss of JMJD1C in subsets of breast carcinomas. These findings identify JMJD1C as a DDR component, with implications for genome-integrity maintenance, tumorigenesis and cancer treatment.
-
homozygous deficiency of ubiquitin ligase ring finger protein rnf168 mimics the radiosensitivity syndrome of ataxia telangiectasia
Cell Death & Differentiation, 2011Co-Authors: S S Devgan, Jiri Lukas, Jiri Bartek, Claudia Lukas, Carsten Doil, O Sanal, Kotoka Nakamura, Shareef A Nahas, Kelly Pettijohn, Richard A GattiAbstract:Maintaining genomic integrity is critical to avoid life-threatening disorders, such as premature aging, neurodegeneration and cancer. A multiprotein cascade operates at sites of DNA double-strand breaks (DSBs) to recognize, signal and repair damage. RNF168 (ring-finger nuclear factor) contributes to this emerging pathway of several E3 ubiquitin ligases that perform sequential Ubiquitylations on damaged chromosomes, chromatin modifications essential for aggregation of repair complexes at the DSB sites. Here, we report the clinical and cellular phenotypes associated with a newly identified homozygous nonsense mutation in the RNF168 gene of a patient with a syndrome mimicking ataxia-telangiectasia. The mutation eliminated both of RNF168's ubiquitin-binding motifs, thus blocking progression of the Ubiquitylation cascade and retention of repair proteins including tumor suppressors 53BP1 and BRCA1 at DSB sites, consistent with the observed defective DNA damage checkpoints/repair and pronounced radiosensitivity. Rapid screening for RNF168 pathway deficiency was achieved by scoring patients' lymphoblastoid cells for irradiation-induced nuclear foci containing 53BP1, a robust assay we propose for future diagnostic applications. The formation of radiation-induced DSB repair foci was rescued by ectopic expression of wild-type RNF168 in patient's cells, further causally linking the RNF168 mutation with the pathology. Clinically, this novel syndrome featured ataxia, telangiectasia, elevated alphafetoprotein, immunodeficiency, microcephaly and pulmonary failure and has implications for the differential diagnosis of autosomal recessive ataxias.
-
Homozygous deficiency of ubiquitin ligase RNF168 defines a radiosensitivity syndrome mimicking ataxia-telangiectasia
Cell Death and Differentiation, 2011Co-Authors: Jiri Bartek, Jiri Lukas, Claudia Lukas, Carsten Doil, S S Devgan, Kotoka Nakamura, Kelly Pettijohn, Shareef Nahas, Richard GattiAbstract:Maintaining genomic integrity is critical to avoid life-threatening disorders such as premature aging, neurodegeneration and cancer. A multiprotein cascade operates at sites of DNA double strand breaks (DSBs) to recognize, signal, and repair damage. RNF168 (ring-finger nuclear factor) contributes to this pathway of several E3 ubiquitin ligases that perform sequential Ubiquitylations on damaged chromosomes, modifications essential for aggregation of repair complexes at the DSB sites. Here we report the clinical and cellular phenotypes associated with a newly identified homozygous nonsense mutation in the RNF168 gene of a patient with a syndrome mimicking ataxia-telangiectasia (A-T). The mutation eliminated both of RNF168's ubiquitin-binding motifs, thus blocking the Ubiquitylation cascade and retention of repair proteins including tumor suppressors 53BP1 and BRCA1 at DSB sites, consistent with the observed defective DNA damage checkpoints/repair and radiosensitivity. Screening for RNF168 pathway deficiency was achieved by scoring patients' lymphoblastoid cells for irradiation-induced nuclear foci containing 53BP1, a robust assay we propose for future diagnostic applications. The formation of radiation-induced DSB repair foci was rescued by ectopic expression of wild-type RNF168 in patient's cells, further causally linking the RNF168 mutation with the pathology. Clinically, this novel syndrome featured ataxia, telangiectasia, elevated alphafetoprotein, immunodeficiency, microcephaly and pulmonary failure and has implications for the differential diagnosis of autosomal recessive ataxias.
-
rnf168 binds and amplifies ubiquitin conjugates on damaged chromosomes to allow accumulation of repair proteins
Cell, 2009Co-Authors: Carsten Doil, Niels Mailand, Simon Bekkerjensen, Patrice Menard, Dorthe Helena Larsen, Rainer Pepperkok, Jan Ellenberg, Stephanie Panier, Daniel Durocher, Jiri BartekAbstract:DNA double-strand breaks (DSBs) not only interrupt the genetic information, but also disrupt the chromatin structure, and both impairments require repair mechanisms to ensure genome integrity. We showed previously that RNF8-mediated chromatin Ubiquitylation protects genome integrity by promoting the accumulation of repair factors at DSBs. Here, we provide evidence that, while RNF8 is necessary to trigger the DSB-associated Ubiquitylations, it is not sufficient to sustain conjugated ubiquitin in this compartment. We identified RNF168 as a novel chromatin-associated ubiquitin ligase with an ability to bind ubiquitin. We show that RNF168 interacts with ubiquitylated H2A, assembles at DSBs in an RNF8-dependent manner, and, by targeting H2A and H2AX, amplifies local concentration of lysine 63-linked ubiquitin conjugates to the threshold required for retention of 53BP1 and BRCA1. Thus, RNF168 defines a new pathway involving sequential Ubiquitylations on damaged chromosomes and uncovers a functional cooperation between E3 ligases in genome maintenance.
Adeline Vitaliano-prunier - One of the best experts on this subject based on the ideXlab platform.
-
H2B Ubiquitylation controls the formation of export-competent mRNP.
Molecular cell, 2012Co-Authors: Adeline Vitaliano-prunier, Carole Gwizdek, Anna Babour, Lucas Hérissant, Luciano H. Apponi, Thanasis Margaritis, Frank C.p. Holstege, Anita H. Corbett, Catherine DargemontAbstract:Histone H2B Ubiquitylation is a transcription-dependent modification that not only regulates nucleosome dynamics but also controls the trimethylation of histone H3 on lysine 4 by promoting Ubiquitylation of Swd2, a component of both the histone methyltransferase COMPASS complex and the cleavage and polyadenylation factor(CPF). We show that preventing either H2B Ubiquitylation or H2B-dependent modification of Swd2 results in nuclear accumulation of poly(A) RNA due to a defect in the integrity and stability of APT, a subcomplex of the CPF. Ubiquitin-regulated APT complex dynamics is required for the correct recruitment of the mRNA export receptor Mex67 to nuclear mRNPs. While H2B Ubiquitylation controls the recruitment of the different Mex67 adaptors to mRNPs, the effect of Swd2 Ubiquitylation is restricted to Yra1 and Nab2, which, in turn, controls poly(A) tail length. Modification of H2B thus participates in the crosstalk between cotranscriptional events and assembly of mRNPs linking nuclear processing and mRNA export.
-
Ubiquitylation of the COMPASS component Swd2 links H2B Ubiquitylation to H3K4 trimethylation
Nature cell biology, 2008Co-Authors: Adeline Vitaliano-prunier, Alexandra Menant, Maria Hobeika, Vincent Géli, Carole Gwizdek, Catherine DargemontAbstract:Mono-Ubiquitylation of histone H2B is required for methylation of histone H3K4. Ubiquitylation of H2B in turn promotes Ubiquitylation of Swd2, a component of the SET1/COMPASS methyltransferase. Inhibiting Swd2 Ubiquitylation impairs recruitment of the COMPASS subunit, which is essential for methylation, and results in reduced H3K4 methylation.
-
Ubiquitylation of the COMPASS component Swd2 links H2B Ubiquitylation to H3K4 trimethylation.
Nature Cell Biology, 2008Co-Authors: Adeline Vitaliano-prunier, Alexandra Menant, Maria Hobeika, Vincent Géli, Carole Gwizdek, Catherine DargemontAbstract:Mono-Ubiquitylation of histone H2B correlates with transcriptional activation and is required for di- and trimethylation at Lys 4 on the histone H3 tail (H3K4) by the SET1/COMPASS methyltransferase complex through a poorly characterized trans-tail pathway. Here we show that mono-Ubiquitylation of histone H2B promotes Ubiquitylation at Lys 68 and Lys 69 of Swd2, the essential component of SET1/COMPASS in Saccharomyces cerevisiae. We found that Rad6/Bre1 Ubiquitylation enzymes responsible for H2B Ubiquitylation also participate directly in Swd2 modification. Preventing Swd2 or H2B Ubiquitylation did not affect Set1 stability, interaction of Swd2 with Set1 or the ability of Swd2 to interact with chromatin. However, we found that mutation of Lys 68 and Lys 69 of Swd2 markedly reduced trimethylation, and to a lesser extent dimethylation, of H3K4 at the 5'-end of transcribing genes without affecting monomethylation. This effect results from the ability of Swd2 Ubiquitylation to control recruitment of Spp1, a COMPASS subunit necessary for trimethylation. Our results further indicate that Swd2 is a major H3-binding component of COMPASS. Swd2 thus represents a key factor that mediates crosstalk between H2B Ubiquitylation and H3K4 trimethylation on chromatin.
Jiri Lukas - One of the best experts on this subject based on the ideXlab platform.
-
jmjd1c demethylates mdc1 to regulate the rnf8 and brca1 mediated chromatin response to dna breaks
Nature Structural & Molecular Biology, 2013Co-Authors: Sugiko Watanabe, Kenji Watanabe, Vyacheslav Akimov, Jirina Bartkova, Blagoy Blagoev, Jiri Lukas, Jiri BartekAbstract:Chromatin Ubiquitylation flanking DNA double-strand breaks (DSBs), mediated by RNF8 and RNF168 ubiquitin ligases, orchestrates a two-branch pathway, recruiting repair factors 53BP1 or the RAP80-BRCA1 complex. We report that human demethylase JMJD1C regulates the RAP80-BRCA1 branch of this DNA-damage response (DDR) pathway. JMJD1C was stabilized by interaction with RNF8, was recruited to DSBs, and was required for local Ubiquitylations and recruitment of RAP80-BRCA1 but not 53BP1. JMJD1C bound to RNF8 and MDC1, and demethylated MDC1 at Lys45, thereby promoting MDC1-RNF8 interaction, RNF8-dependent MDC1 Ubiquitylation and recruitment of RAP80-BRCA1 to polyubiquitylated MDC1. Furthermore, JMJD1C restricted formation of RAD51 repair foci, and JMJD1C depletion caused resistance to ionizing radiation and PARP inhibitors, phenotypes relevant to aberrant loss of JMJD1C in subsets of breast carcinomas. These findings identify JMJD1C as a DDR component, with implications for genome-integrity maintenance, tumorigenesis and cancer treatment.
-
JMJD1C demethylates MDC1 to regulate the RNF8 and BRCA1–mediated chromatin response to DNA breaks
Nature structural & molecular biology, 2013Co-Authors: Sugiko Watanabe, Kenji Watanabe, Vyacheslav Akimov, Jirina Bartkova, Blagoy Blagoev, Jiri Lukas, Jiri BartekAbstract:Chromatin Ubiquitylation flanking DNA double-strand breaks (DSBs), mediated by RNF8 and RNF168 ubiquitin ligases, orchestrates a two-branch pathway, recruiting repair factors 53BP1 or the RAP80-BRCA1 complex. We report that human demethylase JMJD1C regulates the RAP80-BRCA1 branch of this DNA-damage response (DDR) pathway. JMJD1C was stabilized by interaction with RNF8, was recruited to DSBs, and was required for local Ubiquitylations and recruitment of RAP80-BRCA1 but not 53BP1. JMJD1C bound to RNF8 and MDC1, and demethylated MDC1 at Lys45, thereby promoting MDC1-RNF8 interaction, RNF8-dependent MDC1 Ubiquitylation and recruitment of RAP80-BRCA1 to polyubiquitylated MDC1. Furthermore, JMJD1C restricted formation of RAD51 repair foci, and JMJD1C depletion caused resistance to ionizing radiation and PARP inhibitors, phenotypes relevant to aberrant loss of JMJD1C in subsets of breast carcinomas. These findings identify JMJD1C as a DDR component, with implications for genome-integrity maintenance, tumorigenesis and cancer treatment.
-
homozygous deficiency of ubiquitin ligase ring finger protein rnf168 mimics the radiosensitivity syndrome of ataxia telangiectasia
Cell Death & Differentiation, 2011Co-Authors: S S Devgan, Jiri Lukas, Jiri Bartek, Claudia Lukas, Carsten Doil, O Sanal, Kotoka Nakamura, Shareef A Nahas, Kelly Pettijohn, Richard A GattiAbstract:Maintaining genomic integrity is critical to avoid life-threatening disorders, such as premature aging, neurodegeneration and cancer. A multiprotein cascade operates at sites of DNA double-strand breaks (DSBs) to recognize, signal and repair damage. RNF168 (ring-finger nuclear factor) contributes to this emerging pathway of several E3 ubiquitin ligases that perform sequential Ubiquitylations on damaged chromosomes, chromatin modifications essential for aggregation of repair complexes at the DSB sites. Here, we report the clinical and cellular phenotypes associated with a newly identified homozygous nonsense mutation in the RNF168 gene of a patient with a syndrome mimicking ataxia-telangiectasia. The mutation eliminated both of RNF168's ubiquitin-binding motifs, thus blocking progression of the Ubiquitylation cascade and retention of repair proteins including tumor suppressors 53BP1 and BRCA1 at DSB sites, consistent with the observed defective DNA damage checkpoints/repair and pronounced radiosensitivity. Rapid screening for RNF168 pathway deficiency was achieved by scoring patients' lymphoblastoid cells for irradiation-induced nuclear foci containing 53BP1, a robust assay we propose for future diagnostic applications. The formation of radiation-induced DSB repair foci was rescued by ectopic expression of wild-type RNF168 in patient's cells, further causally linking the RNF168 mutation with the pathology. Clinically, this novel syndrome featured ataxia, telangiectasia, elevated alphafetoprotein, immunodeficiency, microcephaly and pulmonary failure and has implications for the differential diagnosis of autosomal recessive ataxias.
-
Homozygous deficiency of ubiquitin ligase RNF168 defines a radiosensitivity syndrome mimicking ataxia-telangiectasia
Cell Death and Differentiation, 2011Co-Authors: Jiri Bartek, Jiri Lukas, Claudia Lukas, Carsten Doil, S S Devgan, Kotoka Nakamura, Kelly Pettijohn, Shareef Nahas, Richard GattiAbstract:Maintaining genomic integrity is critical to avoid life-threatening disorders such as premature aging, neurodegeneration and cancer. A multiprotein cascade operates at sites of DNA double strand breaks (DSBs) to recognize, signal, and repair damage. RNF168 (ring-finger nuclear factor) contributes to this pathway of several E3 ubiquitin ligases that perform sequential Ubiquitylations on damaged chromosomes, modifications essential for aggregation of repair complexes at the DSB sites. Here we report the clinical and cellular phenotypes associated with a newly identified homozygous nonsense mutation in the RNF168 gene of a patient with a syndrome mimicking ataxia-telangiectasia (A-T). The mutation eliminated both of RNF168's ubiquitin-binding motifs, thus blocking the Ubiquitylation cascade and retention of repair proteins including tumor suppressors 53BP1 and BRCA1 at DSB sites, consistent with the observed defective DNA damage checkpoints/repair and radiosensitivity. Screening for RNF168 pathway deficiency was achieved by scoring patients' lymphoblastoid cells for irradiation-induced nuclear foci containing 53BP1, a robust assay we propose for future diagnostic applications. The formation of radiation-induced DSB repair foci was rescued by ectopic expression of wild-type RNF168 in patient's cells, further causally linking the RNF168 mutation with the pathology. Clinically, this novel syndrome featured ataxia, telangiectasia, elevated alphafetoprotein, immunodeficiency, microcephaly and pulmonary failure and has implications for the differential diagnosis of autosomal recessive ataxias.
-
rnf8 ubiquitylates histones at dna double strand breaks and promotes assembly of repair proteins
Cell, 2007Co-Authors: Niels Mailand, Jiri Bartek, Simon Bekkerjensen, Claudia Lukas, Helene Faustrup, Fredrik Melander, Jiri LukasAbstract:Accumulation of repair proteins on damaged chromosomes is required to restore genomic integrity. However, the mechanisms of protein retention at the most destructive chromosomal lesions, the DNA double-strand breaks (DSBs), are poorly understood. We show that RNF8, a RING-finger ubiquitin ligase, rapidly assembles at DSBs via interaction of its FHA domain with the phosphorylated adaptor protein MDC1. This is accompanied by an increase in DSB-associated Ubiquitylations and followed by accumulation of 53BP1 and BRCA1 repair proteins. Knockdown of RNF8 or disruption of its FHA or RING domains impaired DSB-associated Ubiquitylation and inhibited retention of 53BP1 and BRCA1 at the DSB sites. In addition, we show that RNF8 can ubiquitylate histone H2A and H2AX, and that its depletion sensitizes cells to ionizing radiation. These data suggest that MDC1-mediated and RNF8-executed histone Ubiquitylation protects genome integrity by licensing the DSB-flanking chromatin to concentrate repair factors near the DNA lesions.