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Frazier MN, Dillard LB, Krahn JM, Perera L, Williams JG, Wilson IM, Stewart ZD, Pillon MC, Deterding LJ, Borgnia MJ, Stanley RE. Characterization of SARS2 Nsp15 nuclease activity reveals it's mad about U. Nucleic Acids Res 2021; 49:10136-10149. [PMID: 34403466 PMCID: PMC8385992 DOI: 10.1093/nar/gkab719] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/04/2021] [Accepted: 08/09/2021] [Indexed: 12/18/2022] Open
Abstract
Nsp15 is a uridine specific endoribonuclease that coronaviruses employ to cleave viral RNA and evade host immune defense systems. Previous structures of Nsp15 from across Coronaviridae revealed that Nsp15 assembles into a homo-hexamer and has a conserved active site similar to RNase A. Beyond a preference for cleaving RNA 3′ of uridines, it is unknown if Nsp15 has any additional substrate preferences. Here, we used cryo-EM to capture structures of Nsp15 bound to RNA in pre- and post-cleavage states. The structures along with molecular dynamics and biochemical assays revealed critical residues involved in substrate specificity, nuclease activity, and oligomerization. Moreover, we determined how the sequence of the RNA substrate dictates cleavage and found that outside of polyU tracts, Nsp15 has a strong preference for purines 3′ of the cleaved uridine. This work advances our understanding of how Nsp15 recognizes and processes viral RNA, and will aid in the development of new anti-viral therapeutics.
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Affiliation(s)
- Meredith N Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lucas B Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Isha M Wilson
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Zachary D Stewart
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Leesa J Deterding
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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2
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Frazier MN, Pillon MC, Kocaman S, Gordon J, Stanley RE. Structural overview of macromolecular machines involved in ribosome biogenesis. Curr Opin Struct Biol 2021; 67:51-60. [PMID: 33099228 PMCID: PMC8058114 DOI: 10.1016/j.sbi.2020.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/04/2020] [Accepted: 09/08/2020] [Indexed: 12/17/2022]
Abstract
The production of ribosomes is essential for ensuring the translational capacity of cells. Because of its high energy demand ribosome production is subject to stringent cellular controls. Hundreds of ribosome assembly factors are required to facilitate assembly of nascent ribosome particles with high fidelity. Many ribosome assembly factors organize into macromolecular machines that drive complex steps of the production pathway. Recent advances in structural biology, in particular cryo-EM, have provided detailed information about the structure and function of these higher order enzymatic assemblies. Here, we summarize recent structures revealing molecular insight into these macromolecular machines with an emphasis on the interplay between discrete active sites.
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Affiliation(s)
- Meredith N Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Seda Kocaman
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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3
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Pillon MC, Gordon J, Frazier MN, Stanley RE. HEPN RNases - an emerging class of functionally distinct RNA processing and degradation enzymes. Crit Rev Biochem Mol Biol 2021; 56:88-108. [PMID: 33349060 PMCID: PMC7856873 DOI: 10.1080/10409238.2020.1856769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/06/2020] [Accepted: 11/24/2020] [Indexed: 10/22/2022]
Abstract
HEPN (Higher Eukaryotes and Prokaryotes Nucleotide-binding) RNases are an emerging class of functionally diverse RNA processing and degradation enzymes. Members are defined by a small α-helical bundle encompassing a short consensus RNase motif. HEPN dimerization is a universal requirement for RNase activation as the conserved RNase motifs are precisely positioned at the dimer interface to form a composite catalytic center. While the core HEPN fold is conserved, the organization surrounding the HEPN dimer can support large structural deviations that contribute to their specialized functions. HEPN RNases are conserved throughout evolution and include bacterial HEPN RNases such as CRISPR-Cas and toxin-antitoxin associated nucleases, as well as eukaryotic HEPN RNases that adopt large multi-component machines. Here we summarize the canonical elements of the growing HEPN RNase family and identify molecular features that influence RNase function and regulation. We explore similarities and differences between members of the HEPN RNase family and describe the current mechanisms for HEPN RNase activation and inhibition.
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Affiliation(s)
- Monica C. Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Meredith N. Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E. Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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4
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Pillon MC, Frazier MN, Dillard LB, Williams JG, Kocaman S, Krahn JM, Perera L, Hayne CK, Gordon J, Stewart ZD, Sobhany M, Deterding LJ, Hsu AL, Dandey VP, Borgnia MJ, Stanley RE. Cryo-EM structures of the SARS-CoV-2 endoribonuclease Nsp15 reveal insight into nuclease specificity and dynamics. Nat Commun 2021; 12:636. [PMID: 33504779 PMCID: PMC7840905 DOI: 10.1038/s41467-020-20608-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/14/2020] [Indexed: 12/11/2022] Open
Abstract
Nsp15, a uridine specific endoribonuclease conserved across coronaviruses, processes viral RNA to evade detection by host defense systems. Crystal structures of Nsp15 from different coronaviruses have shown a common hexameric assembly, yet how the enzyme recognizes and processes RNA remains poorly understood. Here we report a series of cryo-EM reconstructions of SARS-CoV-2 Nsp15, in both apo and UTP-bound states. The cryo-EM reconstructions, combined with biochemistry, mass spectrometry, and molecular dynamics, expose molecular details of how critical active site residues recognize uridine and facilitate catalysis of the phosphodiester bond. Mass spectrometry revealed the accumulation of cyclic phosphate cleavage products, while analysis of the apo and UTP-bound datasets revealed conformational dynamics not observed by crystal structures that are likely important to facilitate substrate recognition and regulate nuclease activity. Collectively, these findings advance understanding of how Nsp15 processes viral RNA and provide a structural framework for the development of new therapeutics.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA.
| | - Meredith N Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Lucas B Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Seda Kocaman
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Cassandra K Hayne
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
- Cambridge Institute for Medical Research, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
- Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Zachary D Stewart
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Mack Sobhany
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Leesa J Deterding
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Allen L Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Venkata P Dandey
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
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Pillon MC, Frazier MN, Dillard LB, Williams JG, Kocaman S, Krahn JM, Perera L, Hayne CK, Gordon J, Stewart ZD, Sobhany M, Deterding LJ, Hsu AL, Dandey VP, Borgnia MJ, Stanley RE. Cryo-EM Structures of the SARS-CoV-2 Endoribonuclease Nsp15. bioRxiv 2020:2020.08.11.244863. [PMID: 32803198 PMCID: PMC7427136 DOI: 10.1101/2020.08.11.244863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
New therapeutics are urgently needed to inhibit SARS-CoV-2, the virus responsible for the on-going Covid-19 pandemic. Nsp15, a uridine-specific endoribonuclease found in all coronaviruses, processes viral RNA to evade detection by RNA-activated host defense systems, making it a promising drug target. Previous work with SARS-CoV-1 established that Nsp15 is active as a hexamer, yet how Nsp15 recognizes and processes viral RNA remains unknown. Here we report a series of cryo-EM reconstructions of SARS-CoV-2 Nsp15. The UTP-bound cryo-EM reconstruction at 3.36 Å resolution provides molecular details into how critical residues within the Nsp15 active site recognize uridine and facilitate catalysis of the phosphodiester bond, whereas the apo-states reveal active site conformational heterogeneity. We further demonstrate the specificity and mechanism of nuclease activity by analyzing Nsp15 products using mass spectrometry. Collectively, these findings advance understanding of how Nsp15 processes viral RNA and provide a structural framework for the development of new therapeutics.
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Affiliation(s)
- Monica C. Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Meredith N. Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lucas B. Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jason G. Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Seda Kocaman
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Juno M. Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Cassandra K. Hayne
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Zachary D. Stewart
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mack Sobhany
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Leesa J. Deterding
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Allen L. Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Venkata P. Dandey
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mario J. Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E. Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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Abstract
Polynucleotide kinases (PNKs) are enzymes that catalyze the phosphorylation of the 5' hydroxyl end of DNA and RNA oligonucleotides. The activity of PNKs can be quantified using direct or indirect approaches. Presented here is a direct, in vitro approach to measure PNK activity that relies on a fluorescently-labeled oligonucleotide substrate and polyacrylamide gel electrophoresis. This approach provides resolution of the phosphorylated products while avoiding the use of radiolabeled substrates. The protocol details how to set up the phosphorylation reaction, prepare and run large polyacrylamide gels, and quantify the reaction products. The most technically challenging part of this assay is pouring and running the large polyacrylamide gels; thus, important details to overcome common difficulties are provided. This protocol was optimized for Grc3, a PNK that assembles into an obligate pre-ribosomal RNA processing complex with its binding partner, the Las1 nuclease. However, this protocol can be adapted to measure the activity of other PNK enzymes. Moreover, this assay can also be modified to determine the effects of different components of the reaction, such as the nucleoside triphosphate, metal ions, and oligonucleotides.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Department of Health and Human Services, National Institutes of Health
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Department of Health and Human Services, National Institutes of Health;
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7
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Pillon MC, Goslen KH, Gordon J, Wells ML, Williams JG, Stanley RE. It takes two (Las1 HEPN endoribonuclease domains) to cut RNA correctly. J Biol Chem 2020; 295:5857-5870. [PMID: 32220933 DOI: 10.1074/jbc.ra119.011193] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 03/23/2020] [Indexed: 12/26/2022] Open
Abstract
The ribosome biogenesis factor Las1 is an essential endoribonuclease that is well-conserved across eukaryotes and a newly established member of the higher eukaryotes and prokaryotes nucleotide-binding (HEPN) domain-containing nuclease family. HEPN nucleases participate in diverse RNA cleavage pathways and share a short HEPN nuclease motif (RφXXXH) important for RNA cleavage. Most HEPN nucleases participate in stress-activated RNA cleavage pathways; Las1 plays a fundamental role in processing pre-rRNA. Underscoring the significance of Las1 function in the cell, mutations in the human LAS1L (LAS1-like) gene have been associated with neurological dysfunction. Two juxtaposed HEPN nuclease motifs create Las1's composite nuclease active site, but the roles of the individual HEPN motif residues are poorly defined. Here using a combination of in vivo experiments in Saccharomyces cerevisiae and in vitro assays, we show that both HEPN nuclease motifs are required for Las1 nuclease activity and fidelity. Through in-depth sequence analysis and systematic mutagenesis, we determined the consensus HEPN motif in the Las1 subfamily and uncovered its canonical and specialized elements. Using reconstituted Las1 HEPN-HEPN' chimeras, we defined the molecular requirements for RNA cleavage. Intriguingly, both copies of the Las1 HEPN motif were important for nuclease function, revealing that both HEPN motifs participate in coordinating the RNA within the Las1 active site. We also established that conformational flexibility of the two HEPN domains is important for proper nuclease function. The results of our work reveal critical information about how dual HEPN domains come together to drive Las1-mediated RNA cleavage.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Kevin H Goslen
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Melissa L Wells
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709.
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8
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Almawi AW, Scotland MK, Randall JR, Liu L, Martin HK, Sacre L, Shen Y, Pillon MC, Simmons LA, Sutton MD, Guarné A. Binding of the regulatory domain of MutL to the sliding β-clamp is species specific. Nucleic Acids Res 2019; 47:4831-4842. [PMID: 30916336 PMCID: PMC6511837 DOI: 10.1093/nar/gkz115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 01/21/2019] [Accepted: 02/18/2019] [Indexed: 11/15/2022] Open
Abstract
The β-clamp is a protein hub central to DNA replication and fork management. Proteins interacting with the β-clamp harbor a conserved clamp-binding motif that is often found in extended regions. Therefore, clamp interactions have -almost exclusively- been studied using short peptides recapitulating the binding motif. This approach has revealed the molecular determinants that mediate the binding but cannot describe how proteins with clamp-binding motifs embedded in structured domains are recognized. The mismatch repair protein MutL has an internal clamp-binding motif, but its interaction with the β-clamp has different roles depending on the organism. In Bacillus subtilis, the interaction stimulates the endonuclease activity of MutL and it is critical for DNA mismatch repair. Conversely, disrupting the interaction between Escherichia coli MutL and the β-clamp only causes a mild mutator phenotype. Here, we determined the structures of the regulatory domains of E. coli and B. subtilis MutL bound to their respective β-clamps. The structures reveal different binding modes consistent with the binding to the β-clamp being a two-step process. Functional characterization indicates that, within the regulatory domain, only the clamp binding motif is required for the interaction between the two proteins. However, additional motifs beyond the regulatory domain may stabilize the interaction. We propose a model for the activation of the endonuclease activity of MutL in organisms lacking methyl-directed mismatch repair.
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Affiliation(s)
- Ahmad W Almawi
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Michelle K Scotland
- Department of Biochemistry, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.,Witebsky Center for Microbial Pathogenesis and Immunology, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Justin R Randall
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Linda Liu
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Heather K Martin
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Lauralicia Sacre
- Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - Yao Shen
- Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Lyle A Simmons
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Mark D Sutton
- Department of Biochemistry, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.,Witebsky Center for Microbial Pathogenesis and Immunology, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.,Genetics, Genomics and Bioinformatics Program, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.,Department of Biochemistry, McGill University, Montreal, QC, Canada
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9
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Abstract
Cells utilize sophisticated RNA processing machines to ensure the quality of RNA. Many RNA processing machines have been further implicated in regulating the DNA damage response signifying a strong link between RNA processing and genome maintenance. One of the most intricate and highly regulated RNA processing pathways is the processing of the precursor ribosomal RNA (pre-rRNA), which is paramount for the production of ribosomes. Removal of the Internal Transcribed Spacer 2 (ITS2), located between the 5.8S and 25S rRNA, is one of the most complex steps of ribosome assembly. Processing of the ITS2 is initiated by the newly discovered endoribonuclease Las1, which cleaves at the C2 site within the ITS2, generating products that are further processed by the polynucleotide kinase Grc3, the 5'→3' exonuclease Rat1, and the 3'→5' RNA exosome complex. In addition to their defined roles in ITS2 processing, these critical cellular machines participate in other stages of ribosome assembly, turnover of numerous cellular RNAs, and genome maintenance. Here we summarize recent work defining the molecular mechanisms of ITS2 processing by these essential RNA processing machines and highlight their emerging roles in transcription termination, heterochromatin function, telomere maintenance, and DNA repair.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Yu-Hua Lo
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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10
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Pillon MC, Hsu AL, Krahn JM, Williams JG, Goslen KH, Sobhany M, Borgnia MJ, Stanley RE. Cryo-EM reveals active site coordination within a multienzyme pre-rRNA processing complex. Nat Struct Mol Biol 2019; 26:830-839. [PMID: 31488907 PMCID: PMC6733591 DOI: 10.1038/s41594-019-0289-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/30/2019] [Indexed: 12/22/2022]
Abstract
Ribosome assembly is a complex process reliant on the coordination of trans-acting enzymes to produce functional ribosomal subunits and secure the translational capacity of cells. The endoribonuclease (RNase) Las1 and the polynucleotide kinase (PNK) Grc3 assemble into a multienzyme complex, herein designated RNase PNK, to orchestrate processing of precursor ribosomal RNA (rRNA). RNase PNK belongs to the functionally diverse HEPN nuclease superfamily, whose members rely on distinct cues for nuclease activation. To establish how RNase PNK coordinates its dual enzymatic activities, we solved a series of cryo-EM structures of Chaetomium thermophilum RNase PNK in multiple conformational states. The structures reveal that RNase PNK adopts a butterfly-like architecture, harboring a composite HEPN nuclease active site flanked by discrete RNA kinase sites. We identify two molecular switches that coordinate nuclease and kinase function. Together, our structures and corresponding functional studies establish a new mechanism of HEPN nuclease activation essential for ribosome production.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Allen L Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Kevin H Goslen
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Mack Sobhany
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA.
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11
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Gordon J, Pillon MC, Stanley RE. Nol9 Is a Spatial Regulator for the Human ITS2 Pre-rRNA Endonuclease-Kinase Complex. J Mol Biol 2019; 431:3771-3786. [PMID: 31288032 DOI: 10.1016/j.jmb.2019.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 12/01/2022]
Abstract
The ribosome plays a universal role in translating the cellular proteome. Defects in the ribosome assembly factor Las1L are associated with congenital lethal motor neuron disease and X-linked intellectual disability disorders, yet its role in processing precursor ribosomal RNA (pre-rRNA) is largely unclear. The Las1L endoribonuclease associates with the Nol9 polynucleotide kinase to form the internal transcribed spacer 2 (ITS2) pre-rRNA endonuclease-kinase machinery. Together, Las1L-Nol9 catalyzes RNA cleavage and phosphorylation to mark the ITS2 for degradation. While ITS2 processing is critical for the production of functional ribosomes, the regulation of mammalian Las1L-Nol9 remains obscure. Here we characterize the human Las1L-Nol9 complex and identify critical molecular features that regulate its assembly and spatial organization. We establish that Las1L and Nol9 form a higher-order complex and identify the regions responsible for orchestrating this intricate architecture. Structural analysis by high-resolution imaging defines the intricate spatial pattern of Las1L-Nol9 within the nucleolar sub-structure linked with late pre-rRNA processing events. Furthermore, we uncover a Nol9-encoded nucleolar localization sequence that is responsible for nucleolar transport of the assembled Las1L-Nol9 complex. Together, these data provide a mechanism for the assembly and nucleolar localization of the human ITS2 pre-rRNA endonuclease-kinase complex.
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Affiliation(s)
- Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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12
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Mok MCY, Campalans A, Pillon MC, Guarné A, Radicella JP, Junop MS. Identification of an XRCC1 DNA binding activity essential for retention at sites of DNA damage. Sci Rep 2019; 9:3095. [PMID: 30816207 PMCID: PMC6395731 DOI: 10.1038/s41598-019-39543-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/14/2019] [Indexed: 01/21/2023] Open
Abstract
Repair of two major forms of DNA damage, single strand breaks and base modifications, are dependent on XRCC1. XRCC1 orchestrates these repair processes by temporally and spatially coordinating interactions between several other repair proteins. Here we show that XRCC1 contains a central DNA binding domain (CDB, residues 219–415) encompassing its first BRCT domain. In contrast to the N-terminal domain of XRCC1, which has been reported to mediate damage sensing in vitro, we demonstrate that the DNA binding module identified here lacks binding specificity towards DNA containing nicks or gaps. Alanine substitution of residues within the CDB of XRCC1 disrupt DNA binding in vitro and lead to a significant reduction in XRCC1 retention at DNA damage sites without affecting initial recruitment. Interestingly, reduced retention at sites of DNA damage is associated with an increased rate of repair. These findings suggest that DNA binding activity of XRCC1 plays a significant role in retention at sites of damage and the rate at which damage is repaired.
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Affiliation(s)
- Mac C Y Mok
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S4K1, Canada
| | - Anna Campalans
- Institute of Cellular and Molecular Radiobiology, CEA, UMR967 INSERM, F-92265, Fontenay aux Roses, France
| | - Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S4K1, Canada
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S4K1, Canada
| | - J Pablo Radicella
- Institute of Cellular and Molecular Radiobiology, CEA, UMR967 INSERM, F-92265, Fontenay aux Roses, France
| | - Murray S Junop
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S4K1, Canada. .,Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario, N6A5C1, Canada. .,Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario, N6A5C1, Canada.
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13
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Liu L, Ortiz Castro MC, Rodríguez González J, Pillon MC, Guarné A. The endonuclease domain of Bacillus subtilis MutL is functionally asymmetric. DNA Repair (Amst) 2018; 73:1-6. [PMID: 30391220 DOI: 10.1016/j.dnarep.2018.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/10/2018] [Accepted: 10/10/2018] [Indexed: 11/18/2022]
Abstract
DNA mismatch repair is an evolutionarily conserved repair pathway that corrects replication errors. In most prokaryotes and all eukaryotes, the mismatch repair protein MutL is a sequence-unspecific endonuclease that nicks the newly synthesized strand and marks it for repair. Although the sequence of the endonuclease domain of MutL is not conserved, eukaryotic MutLα and prokaryotic MutL share four conserved motifs that define the endonuclease site of the protein. Their endonuclease activity is stimulated by the processivity sliding β-clamp, or its eukaryotic counterpart PCNA, highlighting the functional conservation. Bacterial MutL homologs form homodimers and, therefore, they have two endonuclease sites. However, eukaryotic MutL homologs associate to form heterodimers, where only one of the protomers of the dimer has endonuclease activity. To probe whether bacterial MutL needs its two endonuclease sites, we engineered variants of B. subtilis MutL harboring a single nuclease site and showed that these variants are functional nucleases. We also find that the protomer harboring the nuclease site must be able to bind to the β-clamp to recapitulate the nicking activity of wild-type MutL. These results demonstrate the functional asymmetry of bacterial MutL and strengthen the similarities with the endonuclease activity of eukaryotic MutL homologs.
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Affiliation(s)
- Linda Liu
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | | | | | - Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada; Department of Biochemistry, McGill University, Montreal, QC, Canada.
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14
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Pillon MC, Sobhany M, Stanley RE. Characterization of the molecular crosstalk within the essential Grc3/Las1 pre-rRNA processing complex. RNA 2018; 24:721-738. [PMID: 29440475 PMCID: PMC5900568 DOI: 10.1261/rna.065037.117] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 02/06/2018] [Indexed: 06/08/2023]
Abstract
Grc3 is an essential well-conserved eukaryotic polynucleotide kinase (PNK) that cooperates with the endoribonuclease Las1 to process the preribosomal RNA (rRNA). Aside from being dependent upon Las1 for coordinated kinase and nuclease function, little is known about Grc3 substrate specificity and the molecular mechanisms governing kinase activity. Here we characterize the kinase activity of Grc3 and identify key similarities and differences between Grc3 and other polynucleotide kinase family members. In contrast to other PNK family members, Grc3 has distinct substrate preference for RNA substrates in vitro. By disrupting conserved residues found at the Grc3 kinase active site, we identified specific residues required to support Grc3-directed Las1-mediated pre-rRNA cleavage in vitro and in vivo. The crosstalk between Grc3 and Las1 ensures the direct coupling of cleavage and phosphorylation during pre-rRNA processing. Taken together, our studies provide key insight into the polynucleotide kinase activity of the essential enzyme Grc3 and its molecular crosstalk with the endoribonuclease Las1.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA
| | - Mack Sobhany
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA
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15
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Lo YH, Pillon MC, Stanley RE. Combining X-Ray Crystallography with Small Angle X-Ray Scattering to Model Unstructured Regions of Nsa1 from S. Cerevisiae. J Vis Exp 2018. [PMID: 29364241 DOI: 10.3791/56953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Determination of the full-length structure of ribosome assembly factor Nsa1 from Saccharomyces cerevisiae (S. cerevisiae) is challenging because of the disordered and protease labile C-terminus of the protein. This manuscript describes the methods to purify recombinant Nsa1 from S. cerevisiae for structural analysis by both X-ray crystallography and SAXS. X-ray crystallography was utilized to solve the structure of the well-ordered N-terminal WD40 domain of Nsa1, and then SAXS was used to resolve the structure of the C-terminus of Nsa1 in solution. Solution scattering data was collected from full-length Nsa1 in solution. The theoretical scattering amplitudes were calculated from the high-resolution crystal structure of the WD40 domain, and then a combination of rigid body and ab initio modeling revealed the C-terminus of Nsa1. Through this hybrid approach the quaternary structure of the entire protein was reconstructed. The methods presented here should be generally applicable for the hybrid structural determination of other proteins composed of a mix of structured and unstructured domains.
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Affiliation(s)
- Yu-Hua Lo
- Signal Transduction Laboratory, National Institutes of Environmental Health Sciences, Department of Health and Human Services, National Institutes of Health
| | - Monica C Pillon
- Signal Transduction Laboratory, National Institutes of Environmental Health Sciences, Department of Health and Human Services, National Institutes of Health
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institutes of Environmental Health Sciences, Department of Health and Human Services, National Institutes of Health;
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16
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Pillon MC, Stanley RE. Nuclease integrated kinase super assemblies (NiKs) and their role in RNA processing. Curr Genet 2017; 64:183-190. [PMID: 28929238 DOI: 10.1007/s00294-017-0749-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 01/24/2023]
Abstract
Here we highlight the Grc3/Las1 complex, an essential RNA processing machine that is well conserved across eukaryotes and required for processing the pre-ribosomal RNA (pre-rRNA). Las1 is an endoribonuclease that cleaves the pre-rRNA while Grc3 is a polynucleotide kinase that phosphorylates the Las1-cleaved RNA product. Recently we showed that Grc3 and Las1 assemble into a higher-order complex composed of a dimer of Grc3/Las1 heterodimers that is required for nuclease and kinase activity. Unexpectedly, we found that the Grc3/Las1 complex draws numerous parallels with two other eukaryotic nucleases, Ire1 and RNase L. In this perspective we explore the similarities and differences between this family of nuclease integrated kinase super assemblies (NiKs) and their distinct roles in RNA cleavage.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
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17
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Lo YH, Romes EM, Pillon MC, Sobhany M, Stanley RE. Structural Analysis Reveals Features of Ribosome Assembly Factor Nsa1/WDR74 Important for Localization and Interaction with Rix7/NVL2. Structure 2017; 25:762-772.e4. [PMID: 28416111 DOI: 10.1016/j.str.2017.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/15/2017] [Accepted: 03/13/2017] [Indexed: 01/06/2023]
Abstract
Ribosome assembly is a complex process that requires hundreds of essential assembly factors, including Rix7 (NVL2 in mammals) and Nsa1 (WDR74 in mammals). Rix7 is a type II double ring, AAA-ATPase, which is closely related to the well-known Cdc48/p97. Previous studies in Saccharomyces cerevisiae suggest that Rix7 mediates the release of Nsa1 from nucleolar pre-60S particles; however, the underlying mechanisms of this release are unknown. Through multiple structural analyses we show that S. cerevisiae Nsa1 is composed of an N-terminal seven-bladed WD40 domain followed by a lysine-rich C terminus that extends away from the WD40 domain and is required for nucleolar localization. Co-immunoprecipitation assays with the mammalian homologs identified a well-conserved interface within WDR74 that is important for its association with NVL2. We further show that WDR74 associates with the D1 AAA domain of NVL2, which represents a novel mode of binding of a substrate with a type II AAA-ATPase.
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Affiliation(s)
- Yu-Hua Lo
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Erin M Romes
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Monica C Pillon
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mack Sobhany
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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18
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Wan LCK, Pillon MC, Thevakumaran N, Sun Y, Chakrabartty A, Guarné A, Kurinov I, Durocher D, Sicheri F. Structural and functional characterization of KEOPS dimerization by Pcc1 and its role in t6A biosynthesis. Nucleic Acids Res 2016; 44:6971-80. [PMID: 27302132 PMCID: PMC5001605 DOI: 10.1093/nar/gkw542] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 06/03/2016] [Indexed: 11/20/2022] Open
Abstract
KEOPS is an ancient protein complex required for the biosynthesis of N6-threonylcarbamoyladenosine (t6A), a universally conserved tRNA modification found on all ANN-codon recognizing tRNAs. KEOPS consist minimally of four essential subunits, namely the proteins Kae1, Bud32, Cgi121 and Pcc1, with yeast possessing the fifth essential subunit Gon7. Bud32, Cgi121, Pcc1 and Gon7 appear to have evolved to regulate the central t6A biosynthesis function of Kae1, but their precise function and mechanism of action remains unclear. Pcc1, in particular, binds directly to Kae1 and by virtue of its ability to form dimers in solution and in crystals, Pcc1 was inferred to function as a dimerization module for Kae1 and therefore KEOPS. We now present a 3.4 Å crystal structure of a dimeric Kae1–Pcc1 complex providing direct evidence that Pcc1 can bind and dimerize Kae1. Further biophysical analysis of a complete archaeal KEOPS complex reveals that Pcc1 facilitates KEOPS dimerization in vitro. Interestingly, while Pcc1-mediated dimerization of KEOPS is required to support the growth of yeast, it is dispensable for t6A biosynthesis by archaeal KEOPS in vitro, raising the question of how precisely Pcc1-mediated dimerization impacts cellular biology.
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Affiliation(s)
- Leo C K Wan
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Neroshan Thevakumaran
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Yulong Sun
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1L7, Canada
| | - Avi Chakrabartty
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1L7, Canada
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Igor Kurinov
- Cornell University, Department of Chemistry and Chemical Biology, NE-CAT, Building 436E, Advanced Photon Source, 9700 S. Cass Avenue, Argonne, IL 60439, USA
| | - Daniel Durocher
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E1, Canada Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
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19
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Stogios PJ, Cox G, Spanogiannopoulos P, Pillon MC, Waglechner N, Skarina T, Koteva K, Guarné A, Savchenko A, Wright GD. Rifampin phosphotransferase is an unusual antibiotic resistance kinase. Nat Commun 2016; 7:11343. [PMID: 27103605 PMCID: PMC4844700 DOI: 10.1038/ncomms11343] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/15/2016] [Indexed: 11/11/2022] Open
Abstract
Rifampin (RIF) phosphotransferase (RPH) confers antibiotic resistance by conversion of RIF and ATP, to inactive phospho-RIF, AMP and Pi. Here we present the crystal structure of RPH from Listeria monocytogenes (RPH-Lm), which reveals that the enzyme is comprised of three domains: two substrate-binding domains (ATP-grasp and RIF-binding domains); and a smaller phosphate-carrying His swivel domain. Using solution small-angle X-ray scattering and mutagenesis, we reveal a mechanism where the swivel domain transits between the spatially distinct substrate-binding sites during catalysis. RPHs are previously uncharacterized dikinases that are widespread in environmental and pathogenic bacteria. These enzymes are members of a large unexplored group of bacterial enzymes with substrate affinities that have yet to be fully explored. Such an enzymatically complex mechanism of antibiotic resistance augments the spectrum of strategies used by bacteria to evade antimicrobial compounds.
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Affiliation(s)
- Peter J. Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada M5G 1L6
| | - Georgina Cox
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St W, Hamilton, Ontario, Canada L8S 4K1
| | - Peter Spanogiannopoulos
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St W, Hamilton, Ontario, Canada L8S 4K1
| | - Monica C. Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St W, Hamilton, Ontario, Canada L8S 4K1
| | - Nicholas Waglechner
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St W, Hamilton, Ontario, Canada L8S 4K1
| | - Tatiana Skarina
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St W, Hamilton, Ontario, Canada L8S 4K1
| | - Kalinka Koteva
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St W, Hamilton, Ontario, Canada L8S 4K1
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St W, Hamilton, Ontario, Canada L8S 4K1
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada M5G 1L6
| | - Gerard D. Wright
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St W, Hamilton, Ontario, Canada L8S 4K1
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20
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Pillon MC, Babu VMP, Randall JR, Cai J, Simmons LA, Sutton MD, Guarné A. The sliding clamp tethers the endonuclease domain of MutL to DNA. Nucleic Acids Res 2015; 43:10746-59. [PMID: 26384423 PMCID: PMC4678855 DOI: 10.1093/nar/gkv918] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 08/04/2015] [Accepted: 09/06/2015] [Indexed: 01/05/2023] Open
Abstract
The sliding clamp enhances polymerase processivity and coordinates DNA replication with other critical DNA processing events including translesion synthesis, Okazaki fragment maturation and DNA repair. The relative binding affinity of the sliding clamp for its partners determines how these processes are orchestrated and is essential to ensure the correct processing of newly replicated DNA. However, while stable clamp interactions have been extensively studied; dynamic interactions mediated by the sliding clamp remain poorly understood. Here, we characterize the interaction between the bacterial sliding clamp (β-clamp) and one of its weak-binding partners, the DNA mismatch repair protein MutL. Disruption of this interaction causes a mild mutator phenotype in Escherichia coli, but completely abrogates mismatch repair activity in Bacillus subtilis. We stabilize the MutL-β interaction by engineering two cysteine residues at variable positions of the interface. Using disulfide bridge crosslinking, we have stabilized the E. coli and B. subtilis MutL-β complexes and have characterized their structures using small angle X-ray scattering. We find that the MutL-β interaction greatly stimulates the endonuclease activity of B. subtilis MutL and supports this activity even in the absence of the N-terminal region of the protein.
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Affiliation(s)
- Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Vignesh M P Babu
- Department of Biochemistry, The School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, 14214, USA Witebsky Center for Microbial Pathogenesis and Immunology, The School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, 14214, USA
| | - Justin R Randall
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor MI 48109, USA
| | - Jiudou Cai
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Lyle A Simmons
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor MI 48109, USA
| | - Mark D Sutton
- Department of Biochemistry, The School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, 14214, USA Witebsky Center for Microbial Pathogenesis and Immunology, The School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, 14214, USA Genetics, Genomics and Bioinformatics Program, The School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, 14214, USA
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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21
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Zeqiraj E, Tian L, Piggott CA, Pillon MC, Duffy NM, Ceccarelli DF, Keszei AFA, Lorenzen K, Kurinov I, Orlicky S, Gish GD, Heck AJR, Guarné A, Greenberg RA, Sicheri F. Higher-Order Assembly of BRCC36-KIAA0157 Is Required for DUB Activity and Biological Function. Mol Cell 2015; 59:970-83. [PMID: 26344097 PMCID: PMC4579573 DOI: 10.1016/j.molcel.2015.07.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 06/01/2015] [Accepted: 07/27/2015] [Indexed: 12/11/2022]
Abstract
BRCC36 is a Zn2+ dependent deubiquitinating enzyme (DUB) that hydrolyzes lysine-63-linked ubiquitin chains as part of distinct macromolecular complexes that participate in either interferon signaling or DNA-damage recognition. The MPN+ domain protein BRCC36 associates with pseudo-DUB MPN− proteins KIAA0157 or Abraxas, which are essential for BRCC36 enzymatic activity. To understand the basis for BRCC36 regulation, we have solved the structure of an active BRCC36-KIAA0157 heterodimer and an inactive BRCC36 homodimer. Structural and functional characterizations show how BRCC36 is switched to an active conformation by contacts with KIAA0157. Higher order association of BRCC36 and KIAA0157 into a dimer of heterodimers (super dimers) was required for DUB activity and interaction with targeting proteins SHMT2 and RAP80. These data provide the first explanation of how an inactive pseudo DUB allosterically activates a cognate DUB partner, and implicates super dimerization as a new regulatory mechanism underlying BRCC36 DUB activity, subcellular localization, and biological function.
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Affiliation(s)
- Elton Zeqiraj
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1090, Toronto, ON M5G 1X5, Canada
| | - Lei Tian
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA
| | - Christopher A Piggott
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1090, Toronto, ON M5G 1X5, Canada
| | - Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Nicole M Duffy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1090, Toronto, ON M5G 1X5, Canada
| | - Derek F Ceccarelli
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1090, Toronto, ON M5G 1X5, Canada
| | - Alexander F A Keszei
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1090, Toronto, ON M5G 1X5, Canada; Departments of Biochemistry and Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Kristina Lorenzen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1090, Toronto, ON M5G 1X5, Canada
| | - Igor Kurinov
- Department of Chemistry and Chemical Biology, NE-CAT, Cornell University, Argonne, IL 60439, USA
| | - Stephen Orlicky
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1090, Toronto, ON M5G 1X5, Canada
| | - Gerald D Gish
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1090, Toronto, ON M5G 1X5, Canada
| | - Albert J R Heck
- Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Roger A Greenberg
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA.
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1090, Toronto, ON M5G 1X5, Canada; Departments of Biochemistry and Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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22
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Lenhart JS, Pillon MC, Guarné A, Biteen JS, Simmons LA. Mismatch repair in Gram-positive bacteria. Res Microbiol 2015; 167:4-12. [PMID: 26343983 DOI: 10.1016/j.resmic.2015.08.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/14/2015] [Accepted: 08/26/2015] [Indexed: 12/31/2022]
Abstract
DNA mismatch repair (MMR) is responsible for correcting errors formed during DNA replication. DNA polymerase errors include base mismatches and extra helical nucleotides referred to as insertion and deletion loops. In bacteria, MMR increases the fidelity of the chromosomal DNA replication pathway approximately 100-fold. MMR defects in bacteria reduce replication fidelity and have the potential to affect fitness. In mammals, MMR defects are characterized by an increase in mutation rate and by microsatellite instability. In this review, we discuss current advances in understanding how MMR functions in bacteria lacking the MutH and Dam methylase-dependent MMR pathway.
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Affiliation(s)
- Justin S Lenhart
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States; Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, United States.
| | - Lyle A Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States.
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23
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Huang H, Zeqiraj E, Dong B, Jha BK, Duffy NM, Orlicky S, Thevakumaran N, Talukdar M, Pillon MC, Ceccarelli DF, Wan LCK, Juang YC, Mao DYL, Gaughan C, Brinton MA, Perelygin AA, Kourinov I, Guarné A, Silverman RH, Sicheri F. Dimeric structure of pseudokinase RNase L bound to 2-5A reveals a basis for interferon-induced antiviral activity. Mol Cell 2014; 53:221-34. [PMID: 24462203 PMCID: PMC3974923 DOI: 10.1016/j.molcel.2013.12.025] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 11/21/2013] [Accepted: 12/19/2013] [Indexed: 02/01/2023]
Abstract
RNase L is an ankyrin repeat domain-containing dual endoribonuclease-pseudokinase that is activated by unusual 2,′5′-oligoadenylate (2-5A) second messengers and which impedes viral infections in higher vertebrates. Despite its importance in interferon-regulated antiviral innate immunity, relatively little is known about its precise mechanism of action. Here we present a functional characterization of 2.5 Å and 3.25 Å X-ray crystal and small-angle X-ray scattering structures of RNase L bound to a natural 2-5A activator with and without ADP or the nonhydrolysable ATP mimetic AMP-PNP. These studies reveal how recognition of 2-5A through interactions with the ankyrin repeat domain and the pseudokinase domain, together with nucleotide binding, imposes a rigid intertwined dimer configuration that is essential for RNase catalytic and antiviral functions. The involvement of the pseudokinase domain of RNase L in 2-5A sensing, nucleotide binding, dimerization, and ribonuclease functions highlights the evolutionary adaptability of the eukaryotic protein kinase fold. Structural basis for RNase L regulation by 2-5A and nucleotide (ADP or ATP) binding Recognition of 2-5A is mediated by both ankyrin repeat and protein kinase domains Nucleotide enforces a closed conformation of the kinase domain Nucleotide binding to the pseudokinase domain is essential for RNA cleavage function
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Affiliation(s)
- Hao Huang
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Elton Zeqiraj
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Beihua Dong
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Babal Kant Jha
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Nicole M Duffy
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Stephen Orlicky
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Neroshan Thevakumaran
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Manisha Talukdar
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Derek F Ceccarelli
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Leo C K Wan
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Yu-Chi Juang
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Daniel Y L Mao
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Chemistry and Biology, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Christina Gaughan
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Margo A Brinton
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA
| | | | - Igor Kourinov
- NE-CAT APS, Building 436E, Argonne National Lab, Argonne, IL 60439, USA
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Robert H Silverman
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
| | - Frank Sicheri
- Program in Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
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24
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Lenhart JS, Pillon MC, Guarné A, Simmons LA. Trapping and visualizing intermediate steps in the mismatch repair pathwayin vivo. Mol Microbiol 2013; 90:680-98. [DOI: 10.1111/mmi.12389] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2013] [Indexed: 01/08/2023]
Affiliation(s)
- Justin S. Lenhart
- Department of Molecular, Cellular, and Developmental Biology; University of Michigan; 830 North University Ave Ann Arbor MI 48109-1048 USA
| | - Monica C. Pillon
- Department of Biochemistry and Biomedical Sciences; McMaster University; 1280 Main Street West Hamilton Ontario L8S 4K1 Canada
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences; McMaster University; 1280 Main Street West Hamilton Ontario L8S 4K1 Canada
| | - Lyle A. Simmons
- Department of Molecular, Cellular, and Developmental Biology; University of Michigan; 830 North University Ave Ann Arbor MI 48109-1048 USA
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25
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Pillon MC, Dubinsky M, Johnston RN, Liu SL, Guarné A. Characterization of the defects in the ATP lid of E. coli MutL that cause transient hypermutability. DNA Repair (Amst) 2013; 12:864-9. [PMID: 23916559 DOI: 10.1016/j.dnarep.2013.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 07/05/2013] [Accepted: 07/07/2013] [Indexed: 12/12/2022]
Abstract
Mutator strains spontaneously arise in bacterial populations under stress in an attempt to increase evolutionary adaptation. Inactivation of the ubiquitous DNA mismatch repair pathway, whose normal function is to correct replication errors and hence increase replication fidelity, is often the cause of the mutator phenotype. One of the essential genes in this pathway, mutL, includes a short tandem repeat that is prone to polymerase slippage during replication. While extensive work has established that this repetitive sequence is a genuine genetic switch, the mechanism of MutL inactivation remains unclear. This short tandem repeat is translated into a LALALA motif that resides near the ATPase active site of MutL. Therefore, changes in the length of this motif are presumed to alter the ATPase activity of MutL. We have engineered variants of Escherichia coli MutL with shorter/longer LALALA motifs and characterized their ATPase and DNA binding functions. We have found that the deletion or insertion of a single LA repeat did not compromise the structural integrity of the protein, nor did it affect MutS- or DNA-binding activity. However, it severely compromised ATP binding and, consequently, engagement of the N-terminal domains; both essential activities for proper DNA mismatch repair. These results are discussed in the context of the structure of MutL.
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Affiliation(s)
- Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
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26
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Pillon MC, Miller JH, Guarné A. The endonuclease domain of MutL interacts with the β sliding clamp. DNA Repair (Amst) 2010; 10:87-93. [PMID: 21050827 DOI: 10.1016/j.dnarep.2010.10.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 10/06/2010] [Accepted: 10/07/2010] [Indexed: 10/18/2022]
Abstract
Mismatch repair corrects errors that have escaped polymerase proofreading enhancing replication fidelity by at least two orders of magnitude. The β and PCNA sliding clamps increase the polymerase processivity during DNA replication and are important at several stages of mismatch repair. Both MutS and MutL, the two proteins that initiate the mismatch repair response, interact with β. Binding of MutS to β is important to recruit MutS and MutL to foci. Moreover, the endonuclease activity of human and yeast MutLα is stimulated by PCNA. However, the concrete functions of the processivity clamp in the repair steps preceding DNA resynthesis remain obscure. Here, we demonstrate that the C-terminal domain of MutL encompasses a bona fide β-binding motif that mediates a weak, yet specific, interaction between the two proteins. Mutation of this conserved motif correlates with defects in mismatch repair, demonstrating that the direct interaction with β is important for MutL function. The interaction between the C-terminal domain of MutL and β is conserved in both Bacillus subtilis and Escherichia coli, but the repair defects associated with mutation of this β-binding motif are more severe in the former, suggesting that this interaction may have a more prominent role in methyl-independent than methyl-directed mismatch repair systems. Together with previously published data, our work strongly suggests that β may stimulate the endonuclease activity of MutL through its direct interaction with the C-terminal domain of MutL.
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Affiliation(s)
- Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada
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