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Garcia J, Paul S, Shukla S, Zhong Y, Beauchemin K, Bartholomew B. Conformational switching of Arp5 subunit differentially regulates INO80 chromatin remodeling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.10.593625. [PMID: 38766108 PMCID: PMC11100795 DOI: 10.1101/2024.05.10.593625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The INO80 chromatin remodeler is a versatile enzyme capable of several functions, including spacing nucleosomes equal distances apart, precise positioning of nucleosomes based on DNA shape/sequence and exchanging histone dimers. Within INO80, the Arp5 subunit plays a central role in INO80 remodeling, evidenced by its interactions with the histone octamer, nucleosomal and extranucleosomal DNA, and its necessity in linking INO80's ATPase activity to nucleosome movement. Our investigation reveals that the grappler domain of Arp5 interacts with the acidic pocket of nucleosomes through two distinct mechanisms: an arginine anchor or a hydrophobic/acidic patch. These two modes of binding serve distinct functions within INO80 as shown in vivo by mutations in these regions resulting in varying phenotypes and in vitro by diverse effects on nucleosome mobilization. Our findings suggest that the hydrophobic/acidic patch of Arp5 is likely important for dimer exchange by INO80, while the arginine anchor is crucial for mobilizing nucleosomes.
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Affiliation(s)
- Jeison Garcia
- Department of Epigenetics and Molecular Carcinogenesis, UT MD Anderson Cancer Center, Houston, TX 77054
- Department of Internal Medicine, Division of Medical Genetics. McGovern Medical School, UT Health Science Center at Houston, TX 77030
- These authors contributed equally
| | - Somnath Paul
- Department of Epigenetics and Molecular Carcinogenesis, UT MD Anderson Cancer Center, Houston, TX 77054
- These authors contributed equally
| | - Shagun Shukla
- Department of Epigenetics and Molecular Carcinogenesis, UT MD Anderson Cancer Center, Houston, TX 77054
- These authors contributed equally
| | - Yuan Zhong
- Department of Epigenetics and Molecular Carcinogenesis, UT MD Anderson Cancer Center, Houston, TX 77054
| | - Karissa Beauchemin
- Department of Epigenetics and Molecular Carcinogenesis, UT MD Anderson Cancer Center, Houston, TX 77054
- Department of Biology, Texas A&M University, College Station, TX 77843-3474
| | - Blaine Bartholomew
- Department of Epigenetics and Molecular Carcinogenesis, UT MD Anderson Cancer Center, Houston, TX 77054
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Ferrer P, Upadhyay S, Cai JJ, Clement TM. Novel Nuclear Roles for Testis-Specific ACTL7A and ACTL7B Supported by In Vivo Characterizations and AI Facilitated In Silico Mechanistic Modeling with Implications for Epigenetic Regulation in Spermiogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582797. [PMID: 38464253 PMCID: PMC10925299 DOI: 10.1101/2024.02.29.582797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
A mechanistic role for nuclear function of testis-specific actin related proteins (ARPs) is proposed here through contributions of ARP subunit swapping in canonical chromatin regulatory complexes. This is significant to our understanding of both mechanisms controlling regulation of spermiogenesis, and the expanding functional roles of the ARPs in cell biology. Among these roles, actins and ARPs are pivotal not only in cytoskeletal regulation, but also in intranuclear chromatin organization, influencing gene regulation and nucleosome remodeling. This study focuses on two testis-specific ARPs, ACTL7A and ACTL7B, exploring their intranuclear activities and broader implications utilizing combined in vivo, in vitro, and in silico approaches. ACTL7A and ACTL7B, previously associated with structural roles, are hypothesized here to serve in chromatin regulation during germline development. This study confirms the intranuclear presence of ACTL7B in spermatocytes and round spermatids, revealing a potential role in intranuclear processes, and identifies a putative nuclear localization sequence conserved across mammalian ACTL7B, indicating a potentially unique mode of nuclear transport which differs from conventional actin. Ablation of ACTL7B leads to varied transcriptional changes reported here. Additionally, in the absence of ACTL7A or ACTL7B there is a loss of intranuclear localization of HDAC1 and HDAC3, which are known regulators of epigenetic associated acetylation changes that in turn regulate gene expression. Thus, these HDACs are implicated as contributors to the aberrant gene expression observed in the KO mouse testis transcriptomic analysis. Furthermore, this study employed and confirmed the accuracy of in silico models to predict ARP interactions with Helicase-SANT-associated (HSA) domains, uncovering putative roles for testis-specific ARPs in nucleosome remodeling complexes. In these models, ACTL7A and ACTL7B were found capable of binding to INO80 and SWI/SNF nucleosome remodeler family members in a manner akin to nuclear actin and ACTL6A. These models thus implicate germline-specific ARP subunit swapping within chromatin regulatory complexes as a potential regulatory mechanism for chromatin and associated molecular machinery adaptations in nuclear reorganizations required during spermiogenesis. These results hold implications for male fertility and epigenetic programing in the male-germline that warrant significant future investigation. In summary, this study reveals that ACTL7A and ACTL7B play intranuclear gene regulation roles in male gametogenesis, adding to the multifaceted roles identified also spanning structural, acrosomal, and flagellar stability. ACTL7A and ACTL7B unique nuclear transport, impact on HDAC nuclear associations, impact on transcriptional processes, and proposed mechanism for involvement in nucleosome remodeling complexes supported by AI facilitated in silico modeling contribute to a more comprehensive understanding of the indispensable functions of ARPs broadly in cell biology, and specifically in male fertility.
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Affiliation(s)
- Pierre Ferrer
- Interdisciplinary Faculty of Toxicology Program, Texas A&M University, College Station, TX 77843
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843
| | - Srijana Upadhyay
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843
| | - James J Cai
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843
| | - Tracy M Clement
- Interdisciplinary Faculty of Toxicology Program, Texas A&M University, College Station, TX 77843
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843
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3
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Bartholomew B, Shukla S, Ngubo M, Paul S, Persinger J, Brahma S. New insights into the mechanism and DNA-sequence specificity of INO80 chromatin remodeling. RESEARCH SQUARE 2023:rs.3.rs-3443329. [PMID: 37961512 PMCID: PMC10635376 DOI: 10.21203/rs.3.rs-3443329/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The INO80 complex stood out in a large family of ATP-dependent chromatin remodelers because of its ATPase domain binding and translocating on DNA at the edge of nucleosomes, rather than at two helical turns from the center of DNA that is wrapped around nucleosomes. This unique property of INO80 was thought to account for its singular role in nucleosome placement at gene promoters in a DNA-sequence dependent manner that is crucial for transcription regulation. Now, we uncover INO80 functions differently than previously thought with its ATPase domain translocating on DNA close to the center of nucleosomes, like other remodelers. Our discovery also reveals the physical properties of the first ~36 bp of DNA on the entry side of nucleosomes is the main determinant for the DNA specificity of INO80 rather than the properties of the extranucleosomal DNA. The DNA sequence sensitive step of INO80 is after DNA is displaced from the histone octamer on the entry side of nucleosomes and 20 bp of DNA are moved out the exit side. We find the ATPase domain and Arp5 subunit of INO80 are likely involved in INO80's DNA specificity and the mechanism of INO80 remodeling is substantially different than originally proposed.
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4
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Hsieh LJ, Gourdet MA, Moore CM, Muñoz EN, Gamarra N, Ramani V, Narlikar GJ. A hexasome is the preferred substrate for the INO80 chromatin remodeling complex, allowing versatility of function. Mol Cell 2022; 82:2098-2112.e4. [PMID: 35597239 PMCID: PMC9351570 DOI: 10.1016/j.molcel.2022.04.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 12/10/2021] [Accepted: 04/20/2022] [Indexed: 10/18/2022]
Abstract
The critical role of the INO80 chromatin remodeling complex in transcription is commonly attributed to its nucleosome sliding activity. Here, we have found that INO80 prefers to mobilize hexasomes over nucleosomes. INO80's preference for hexasomes reaches up to ∼60 fold when flanking DNA overhangs approach ∼18-bp linkers in yeast gene bodies. Correspondingly, deletion of INO80 significantly affects the positions of hexasome-sized particles within yeast genes in vivo. Our results raise the possibility that INO80 promotes nucleosome sliding by dislodging an H2A-H2B dimer, thereby making a nucleosome transiently resemble a hexasome. We propose that this mechanism allows INO80 to rapidly mobilize nucleosomes at promoters and hexasomes within gene bodies. Rapid repositioning of hexasomes that are generated in the wake of transcription may mitigate spurious transcription. More generally, such versatility may explain how INO80 regulates chromatin architecture during the diverse processes of transcription, replication, and repair.
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Affiliation(s)
- Laura J Hsieh
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Muryam A Gourdet
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Camille M Moore
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Elise N Muñoz
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Nathan Gamarra
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Vijay Ramani
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Geeta J Narlikar
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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Morita T, Hayashi K. Actin-related protein 5 functions as a novel modulator of MyoD and MyoG in skeletal muscle and in rhabdomyosarcoma. eLife 2022; 11:77746. [PMID: 35348112 PMCID: PMC8983046 DOI: 10.7554/elife.77746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Myogenic regulatory factors (MRFs) are pivotal transcription factors in myogenic differentiation. MyoD commits cells to the skeletal muscle lineage by inducing myogenic genes through recruitment of chromatin remodelers to its target loci. This study showed that Actin-related protein 5 (Arp5) acts as an inhibitory regulator of MyoD and MyoG by binding to their cysteine-rich (CR) region, which overlaps with the region essential for their epigenetic functions. Arp5 expression was faint in skeletal muscle tissues. Excessive Arp5 in mouse hind limbs caused skeletal muscle fiber atrophy. Further, Arp5 overexpression in myoblasts inhibited myotube formation by diminishing myogenic gene expression, whereas Arp5 depletion augmented myogenic gene expression. Arp5 disturbed MyoD-mediated chromatin remodeling through competition with the three-amino-acid-loop-extension-class homeodomain transcription factors the Pbx1–Meis1 heterodimer for binding to the CR region. This antimyogenic function was independent of the INO80 chromatin remodeling complex, although Arp5 is an important component of that. In rhabdomyosarcoma (RMS) cells, Arp5 expression was significantly higher than in normal myoblasts and skeletal muscle tissue, probably contributing to MyoD and MyoG activity dysregulation. Arp5 depletion in RMS partially restored myogenic properties while inhibiting tumorigenic properties. Thus, Arp5 is a novel modulator of MRFs in skeletal muscle differentiation.
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Abstract
Actin is a highly conserved protein in mammals. The actin dynamics is regulated by actin-binding proteins and actin-related proteins. Nuclear actin and these regulatory proteins participate in multiple nuclear processes, including chromosome architecture organization, chromatin remodeling, transcription machinery regulation, and DNA repair. It is well known that the dysfunctions of these processes contribute to the development of cancer. Moreover, emerging evidence has shown that the deregulated actin dynamics is also related to cancer. This chapter discusses how the deregulation of nuclear actin dynamics contributes to tumorigenesis via such various nuclear events.
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Affiliation(s)
- Yuanjian Huang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shengzhe Zhang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jae-Il Park
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center and Health Science Center, Houston, TX, USA.
- Program in Genetics and Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Cheon Y, Han S, Kim T, Hwang D, Lee D. The chromatin remodeler Ino80 mediates RNAPII pausing site determination. Genome Biol 2021; 22:294. [PMID: 34663418 PMCID: PMC8524862 DOI: 10.1186/s13059-021-02500-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 09/15/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Promoter-proximal pausing of RNA polymerase II (RNAPII) is a critical step for the precise regulation of gene expression. Despite the apparent close relationship between promoter-proximal pausing and nucleosome, the role of chromatin remodeler governing this step has mainly remained elusive. RESULTS Here, we report highly confined RNAPII enrichments downstream of the transcriptional start site in Saccharomyces cerevisiae using PRO-seq experiments. This non-uniform distribution of RNAPII exhibits both similar and different characteristics with promoter-proximal pausing in Schizosaccharomyces pombe and metazoans. Interestingly, we find that Ino80p knockdown causes a significant upstream transition of promoter-proximal RNAPII for a subset of genes, relocating RNAPII from the main pausing site to the alternative pausing site. The proper positioning of RNAPII is largely dependent on nucleosome context. We reveal that the alternative pausing site is closely associated with the + 1 nucleosome, and nucleosome architecture around the main pausing site of these genes is highly phased. In addition, Ino80p knockdown results in an increase in fuzziness and a decrease in stability of the + 1 nucleosome. Furthermore, the loss of INO80 also leads to the shift of promoter-proximal RNAPII toward the alternative pausing site in mouse embryonic stem cells. CONCLUSIONS Based on our collective results, we hypothesize that the highly conserved chromatin remodeler Ino80p is essential in establishing intact RNAPII pausing during early transcription elongation in various organisms, from budding yeast to mouse.
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Affiliation(s)
- Youngseo Cheon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Sungwook Han
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Taemook Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Daehee Hwang
- School of Biological Sciences, Seoul National University, Seoul, 08826, South Korea
| | - Daeyoup Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea.
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8
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Clapier CR. Sophisticated Conversations between Chromatin and Chromatin Remodelers, and Dissonances in Cancer. Int J Mol Sci 2021; 22:5578. [PMID: 34070411 PMCID: PMC8197500 DOI: 10.3390/ijms22115578] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 01/13/2023] Open
Abstract
The establishment and maintenance of genome packaging into chromatin contribute to define specific cellular identity and function. Dynamic regulation of chromatin organization and nucleosome positioning are critical to all DNA transactions-in particular, the regulation of gene expression-and involve the cooperative action of sequence-specific DNA-binding factors, histone modifying enzymes, and remodelers. Remodelers are molecular machines that generate various chromatin landscapes, adjust nucleosome positioning, and alter DNA accessibility by using ATP binding and hydrolysis to perform DNA translocation, which is highly regulated through sophisticated structural and functional conversations with nucleosomes. In this review, I first present the functional and structural diversity of remodelers, while emphasizing the basic mechanism of DNA translocation, the common regulatory aspects, and the hand-in-hand progressive increase in complexity of the regulatory conversations between remodelers and nucleosomes that accompanies the increase in challenges of remodeling processes. Next, I examine how, through nucleosome positioning, remodelers guide the regulation of gene expression. Finally, I explore various aspects of how alterations/mutations in remodelers introduce dissonance into the conversations between remodelers and nucleosomes, modify chromatin organization, and contribute to oncogenesis.
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Affiliation(s)
- Cedric R Clapier
- Department of Oncological Sciences & Howard Hughes Medical Institute, Huntsman Cancer Institute, University of Utah School of Medicine, 2000 Circle of Hope, Salt Lake City, UT 84112, USA
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9
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Willhoft O, Wigley DB. INO80 and SWR1 complexes: the non-identical twins of chromatin remodelling. Curr Opin Struct Biol 2020; 61:50-58. [PMID: 31838293 PMCID: PMC7171469 DOI: 10.1016/j.sbi.2019.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/07/2019] [Indexed: 02/06/2023]
Abstract
The INO80 family of chromatin remodellers are multisubunit complexes that perform a variety of tasks on nucleosomes. Family members are built around a heterohexamer of RuvB-like protein, an ATP-dependent DNA translocase,nuclear actin and actin-related proteins, and a few complex-specific subunits. They modify chromatin in a number of ways including nucleosome sliding and exchange of variant histones. Recent structural information on INO80 and SWR1 complexes has revealed similarities in the basic architecture of the complexes. However, structural and biochemical data on the complexes bound to nucleosomes reveal these similarities to be somewhat superficial and their biochemical activities and mechanisms are very different. Consequently, the INO80 family displays a surprising diversity of function that is based upon a similar structural framework.
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Affiliation(s)
- Oliver Willhoft
- Section of Structural and Synthetic Biology, Dept. Infectious Disease, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Dale B Wigley
- Section of Structural and Synthetic Biology, Dept. Infectious Disease, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK.
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10
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INO80 Chromatin Remodeling Coordinates Metabolic Homeostasis with Cell Division. Cell Rep 2019; 22:611-623. [PMID: 29346761 PMCID: PMC5949282 DOI: 10.1016/j.celrep.2017.12.079] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 12/19/2017] [Accepted: 12/21/2017] [Indexed: 12/13/2022] Open
Abstract
Adaptive survival requires the coordination of nutrient availability with expenditure of cellular resources. For example, in nutrient-limited environments, 50% of all S. cerevisiae genes synchronize and exhibit periodic bursts of expression in coordination with respiration and cell division in the yeast metabolic cycle (YMC). Despite the importance of metabolic and proliferative synchrony, the majority of YMC regulators are currently unknown. Here, we demonstrate that the INO80 chromatin-remodeling complex is required to coordinate respiration and cell division with periodic gene expression. Specifically, INO80 mutants have severe defects in oxygen consumption and promiscuous cell division that is no longer coupled with metabolic status. In mutant cells, chromatin accessibility of periodic genes, including TORC1-responsive genes, is relatively static, concomitant with severely attenuated gene expression. Collectively, these results reveal that the INO80 complex mediates metabolic signaling to chromatin to restrict proliferation to metabolically optimal states.
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11
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Ricketts MD, Han J, Szurgot MR, Marmorstein R. Molecular basis for chromatin assembly and modification by multiprotein complexes. Protein Sci 2018; 28:329-343. [PMID: 30350439 DOI: 10.1002/pro.3535] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 10/05/2018] [Accepted: 10/08/2018] [Indexed: 12/29/2022]
Abstract
Epigenetic regulation of the chromatin landscape is often orchestrated through modulation of nucleosomes. Nucleosomes are composed of two copies each of the four core histones, H2A, H2B, H3, and H4, wrapped in ~150 bp of DNA. We focus this review on recent structural studies that further elucidate the mechanisms used by macromolecular complexes to mediate histone modification and nucleosome assembly. Nucleosome assembly, spacing, and variant histone incorporation are coordinated by chromatin remodeler and histone chaperone complexes. Several recent structural studies highlight how disparate families of histone chaperones and chromatin remodelers share similar features that underlie how they interact with their respective histone or nucleosome substrates. Post-translational modification of histone residues is mediated by enzymatic subunits within large complexes. Until recently, relatively little was known about how association with auxiliary subunits serves to modulate the activity and specificity of the enzymatic subunit. Analysis of several recent structures highlights the different modes that auxiliary subunits use to influence enzymatic activity or direct specificity toward individual histone residues.
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Affiliation(s)
- M Daniel Ricketts
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, 19104.,Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, Pennsylvania, 19104
| | - Joseph Han
- Department of Chemistry Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, 19104
| | - Mary R Szurgot
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, 19104
| | - Ronen Marmorstein
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, 19104.,Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, Pennsylvania, 19104.,Department of Chemistry Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, 19104.,Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, 19104
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12
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Willhoft O, Ghoneim M, Lin CL, Chua EYD, Wilkinson M, Chaban Y, Ayala R, McCormack EA, Ocloo L, Rueda DS, Wigley DB. Structure and dynamics of the yeast SWR1-nucleosome complex. Science 2018; 362:362/6411/eaat7716. [PMID: 30309918 DOI: 10.1126/science.aat7716] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/08/2018] [Indexed: 12/31/2022]
Abstract
The yeast SWR1 complex exchanges histone H2A in nucleosomes with Htz1 (H2A.Z in humans). The cryo-electron microscopy structure of the SWR1 complex bound to a nucleosome at 3.6-angstrom resolution reveals details of the intricate interactions between components of the SWR1 complex and its nucleosome substrate. Interactions between the Swr1 motor domains and the DNA wrap at superhelical location 2 distort the DNA, causing a bulge with concomitant translocation of the DNA by one base pair, coupled to conformational changes of the histone core. Furthermore, partial unwrapping of the DNA from the histone core takes place upon binding of nucleosomes to SWR1 complex. The unwrapping, as monitored by single-molecule data, is stabilized and has its dynamics altered by adenosine triphosphate binding but does not require hydrolysis.
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Affiliation(s)
- Oliver Willhoft
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Mohamed Ghoneim
- Single Molecule Imaging Group, MRC London Institute of Medical Sciences, London W12 0NN, UK.,Molecular Virology, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Chia-Liang Lin
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Eugene Y D Chua
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Martin Wilkinson
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Yuriy Chaban
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Rafael Ayala
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Elizabeth A McCormack
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Lorraine Ocloo
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - David S Rueda
- Single Molecule Imaging Group, MRC London Institute of Medical Sciences, London W12 0NN, UK. .,Molecular Virology, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Dale B Wigley
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK.
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13
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Regulation of ATP-dependent chromatin remodelers: accelerators/brakes, anchors and sensors. Biochem Soc Trans 2018; 46:1423-1430. [PMID: 30467122 DOI: 10.1042/bst20180043] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/17/2018] [Accepted: 10/18/2018] [Indexed: 12/20/2022]
Abstract
All ATP-dependent chromatin remodelers have a DNA translocase domain that moves along double-stranded DNA when hydrolyzing ATP, which is the key action leading to DNA moving through nucleosomes. Recent structural and biochemical data from a variety of different chromatin remodelers have revealed that there are three basic ways in which these remodelers self-regulate their chromatin remodeling activity. In several instances, different domains within the catalytic subunit or accessory subunits through direct protein-protein interactions can modulate the ATPase and DNA translocation properties of the DNA translocase domain. These domains or subunits can stabilize conformations that either promote or interfere with the ability of the translocase domain to bind or retain DNA during translocation or alter the ability of the enzyme to hydrolyze ATP. Second, other domains or subunits are often necessary to anchor the remodeler to nucleosomes to couple DNA translocation and ATP hydrolysis to DNA movement around the histone octamer. These anchors provide a fixed point by which remodelers can generate sufficient torque to disrupt histone-DNA interactions and mobilize nucleosomes. The third type of self-regulation is in those chromatin remodelers that space nucleosomes or stop moving nucleosomes when a particular length of linker DNA has been reached. We refer to this third class as DNA sensors that can allosterically regulate nucleosome mobilization. In this review, we will show examples of these from primarily the INO80/SWR1, SWI/SNF and ISWI/CHD families of remodelers.
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14
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Brahma S, Ngubo M, Paul S, Udugama M, Bartholomew B. The Arp8 and Arp4 module acts as a DNA sensor controlling INO80 chromatin remodeling. Nat Commun 2018; 9:3309. [PMID: 30120252 PMCID: PMC6098158 DOI: 10.1038/s41467-018-05710-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 07/17/2018] [Indexed: 02/06/2023] Open
Abstract
Nuclear actin and actin-related proteins (Arps) are key components of chromatin remodeling and modifying complexes. Although Arps are essential for the functions of chromatin remodelers, their specific roles and mechanisms are unclear. Here we define the nucleosome binding interfaces and functions of the evolutionarily conserved Arps in the yeast INO80 chromatin remodeling complex. We show that the N-terminus of Arp8, C-terminus of Arp4 and the HSA domain of Ino80 bind extranucleosomal DNA 37-51 base pairs from the edge of nucleosomes and function as a DNA-length sensor that regulates nucleosome sliding by INO80. Disruption of Arp8 and Arp4 binding to DNA uncouples ATP hydrolysis from nucleosome mobilization by disengaging Arp5 from the acidic patch on histone H2A-H2B and the Ino80-ATPase domain from the Super-helical Location (SHL) -6 of nucleosomes. Our data suggest a functional interplay between INO80's Arp8-Arp4-actin and Arp5 modules in sensing the DNA length separating nucleosomes and regulating nucleosome positioning.
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Affiliation(s)
- Sandipan Brahma
- Department of Epigenetics & Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, 78957, USA.,Center for Cancer Epigenetics, MD Anderson Cancer Center, Smithville, TX, 78957, USA.,Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Mzwanele Ngubo
- Department of Epigenetics & Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, 78957, USA.,Center for Cancer Epigenetics, MD Anderson Cancer Center, Smithville, TX, 78957, USA
| | - Somnath Paul
- Department of Epigenetics & Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, 78957, USA.,Center for Cancer Epigenetics, MD Anderson Cancer Center, Smithville, TX, 78957, USA
| | - Maheshi Udugama
- Department of Biochemistry and Molecular Biology, Southern Illinois University, 1245 Lincoln Drive, Carbondale, 62901, USA.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic, 3800, Australia
| | - Blaine Bartholomew
- Department of Epigenetics & Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, 78957, USA. .,Center for Cancer Epigenetics, MD Anderson Cancer Center, Smithville, TX, 78957, USA.
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15
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Morrison AJ. Genome maintenance functions of the INO80 chromatin remodeller. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0289. [PMID: 28847826 DOI: 10.1098/rstb.2016.0289] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2017] [Indexed: 12/15/2022] Open
Abstract
Chromatin modification is conserved in all eukaryotes and is required to facilitate and regulate DNA-templated processes. For example, chromatin manipulation, such as histone post-translational modification and nucleosome positioning, play critical roles in genome stability pathways. The INO80 chromatin-remodelling complex, which regulates the abundance and positioning of nucleosomes, is particularly important for proper execution of inducible responses to DNA damage. This review discusses the participation and activity of the INO80 complex in DNA repair and cell cycle checkpoint pathways, with emphasis on the Saccharomyces cerevisiae model system. Furthermore, the role of ATM/ATR kinases, central regulators of DNA damage signalling, in the regulation of INO80 function will be reviewed. In addition, emerging themes of chromatin remodelling in mitotic stability pathways and chromosome segregation will be introduced. These studies are critical to understanding the dynamic chromatin landscape that is rapidly and reversibly modified to maintain the integrity of the genome.This article is part of the themed issue 'Chromatin modifiers and remodellers in DNA repair and signalling'.
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Affiliation(s)
- Ashby J Morrison
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
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16
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Ayala R, Willhoft O, Aramayo RJ, Wilkinson M, McCormack EA, Ocloo L, Wigley DB, Zhang X. Structure and regulation of the human INO80-nucleosome complex. Nature 2018; 556:391-395. [PMID: 29643506 PMCID: PMC5937682 DOI: 10.1038/s41586-018-0021-6] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 02/16/2018] [Indexed: 01/15/2023]
Abstract
Access to DNA within nucleosomes is required for a variety of processes in cells including transcription, replication and repair. Consequently, cells encode multiple systems that remodel nucleosomes. These complexes can be simple, involving one or a few protein subunits, or more complicated multi-subunit machines 1 . Biochemical studies2-4 have placed the motor domains of several chromatin remodellers in the superhelical location 2 region of the nucleosome. Structural studies of yeast Chd1 and Snf2-a subunit in the complex with the capacity to remodel the structure of chromatin (RSC)-in complex with nucleosomes5-7 have provided insights into the basic mechanism of nucleosome sliding performed by these complexes. However, how larger, multi-subunit remodelling complexes such as INO80 interact with nucleosomes and how remodellers carry out functions such as nucleosome sliding 8 , histone exchange 9 and nucleosome spacing10-12 remain poorly understood. Although some remodellers work as monomers 13 , others work as highly cooperative dimers11, 14, 15. Here we present the structure of the human INO80 chromatin remodeller with a bound nucleosome, which reveals that INO80 interacts with nucleosomes in a previously undescribed manner: the motor domains are located on the DNA at the entry point to the nucleosome, rather than at superhelical location 2. The ARP5-IES6 module of INO80 makes additional contacts on the opposite side of the nucleosome. This arrangement enables the histone H3 tails of the nucleosome to have a role in the regulation of the activities of the INO80 motor domain-unlike in other characterized remodellers, for which H4 tails have been shown to regulate the motor domains.
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Affiliation(s)
- Rafael Ayala
- Section of Structural Biology, Dept. Medicine, Imperial College London, London, UK
| | - Oliver Willhoft
- Section of Structural Biology, Dept. Medicine, Imperial College London, London, UK
| | - Ricardo J Aramayo
- Section of Structural Biology, Dept. Medicine, Imperial College London, London, UK
| | - Martin Wilkinson
- Section of Structural Biology, Dept. Medicine, Imperial College London, London, UK
| | | | - Lorraine Ocloo
- Section of Structural Biology, Dept. Medicine, Imperial College London, London, UK
| | - Dale B Wigley
- Section of Structural Biology, Dept. Medicine, Imperial College London, London, UK.
| | - Xiaodong Zhang
- Section of Structural Biology, Dept. Medicine, Imperial College London, London, UK.
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17
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Beckwith SL, Schwartz EK, García-Nieto PE, King DA, Gowans GJ, Wong KM, Eckley TL, Paraschuk AP, Peltan EL, Lee LR, Yao W, Morrison AJ. The INO80 chromatin remodeler sustains metabolic stability by promoting TOR signaling and regulating histone acetylation. PLoS Genet 2018; 14:e1007216. [PMID: 29462149 PMCID: PMC5834206 DOI: 10.1371/journal.pgen.1007216] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 03/02/2018] [Accepted: 01/23/2018] [Indexed: 12/16/2022] Open
Abstract
Chromatin remodeling complexes are essential for gene expression programs that coordinate cell function with metabolic status. However, how these remodelers are integrated in metabolic stability pathways is not well known. Here, we report an expansive genetic screen with chromatin remodelers and metabolic regulators in Saccharomyces cerevisiae. We found that, unlike the SWR1 remodeler, the INO80 chromatin remodeling complex is composed of multiple distinct functional subunit modules. We identified a strikingly divergent genetic signature for the Ies6 subunit module that links the INO80 complex to metabolic homeostasis. In particular, mitochondrial maintenance is disrupted in ies6 mutants. INO80 is also needed to communicate TORC1-mediated signaling to chromatin, as ino80 mutants exhibit defective transcriptional profiles and altered histone acetylation of TORC1-responsive genes. Furthermore, comparative analysis reveals subunits of INO80 and mTORC1 have high co-occurrence of alterations in human cancers. Collectively, these results demonstrate that the INO80 complex is a central component of metabolic homeostasis that influences histone acetylation and may contribute to disease when disrupted.
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Affiliation(s)
- Sean L. Beckwith
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Erin K. Schwartz
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | | | - Devin A. King
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Graeme J. Gowans
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Ka Man Wong
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Tessa L. Eckley
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | | | - Egan L. Peltan
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Laura R. Lee
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Wei Yao
- Department of Biology, Stanford University, Stanford, CA, United States of America
| | - Ashby J. Morrison
- Department of Biology, Stanford University, Stanford, CA, United States of America
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18
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Clapier CR, Iwasa J, Cairns BR, Peterson CL. Mechanisms of action and regulation of ATP-dependent chromatin-remodelling complexes. Nat Rev Mol Cell Biol 2017; 18:407-422. [PMID: 28512350 DOI: 10.1038/nrm.2017.26] [Citation(s) in RCA: 691] [Impact Index Per Article: 98.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cells utilize diverse ATP-dependent nucleosome-remodelling complexes to carry out histone sliding, ejection or the incorporation of histone variants, suggesting that different mechanisms of action are used by the various chromatin-remodelling complex subfamilies. However, all chromatin-remodelling complex subfamilies contain an ATPase-translocase 'motor' that translocates DNA from a common location within the nucleosome. In this Review, we discuss (and illustrate with animations) an alternative, unifying mechanism of chromatin remodelling, which is based on the regulation of DNA translocation. We propose the 'hourglass' model of remodeller function, in which each remodeller subfamily utilizes diverse specialized proteins and protein domains to assist in nucleosome targeting or to differentially detect nucleosome epitopes. These modules converge to regulate a common DNA translocation mechanism, to inform the conserved ATPase 'motor' on whether and how to apply DNA translocation, which together achieve the various outcomes of chromatin remodelling: nucleosome assembly, chromatin access and nucleosome editing.
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Affiliation(s)
- Cedric R Clapier
- Howard Hughes Medical Institute and Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Janet Iwasa
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Bradley R Cairns
- Howard Hughes Medical Institute and Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Craig L Peterson
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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19
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Takahashi Y, Murakami H, Akiyama Y, Katoh Y, Oma Y, Nishijima H, Shibahara KI, Igarashi K, Harata M. Actin Family Proteins in the Human INO80 Chromatin Remodeling Complex Exhibit Functional Roles in the Induction of Heme Oxygenase-1 with Hemin. Front Genet 2017; 8:17. [PMID: 28270832 PMCID: PMC5318382 DOI: 10.3389/fgene.2017.00017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 02/06/2017] [Indexed: 11/13/2022] Open
Abstract
Nuclear actin family proteins, comprising of actin and actin-related proteins (Arps), are essential functional components of the multiple chromatin remodeling complexes. The INO80 chromatin remodeling complex, which is evolutionarily conserved and has roles in transcription, DNA replication and repair, consists of actin and actin-related proteins Arp4, Arp5, and Arp8. We generated Arp5 knockout (KO) and Arp8 KO cells from the human Nalm-6 pre-B cell line and used these KO cells to examine the roles of Arp5 and Arp8 in the transcriptional regulation mediated by the INO80 complex. In both of Arp5 KO and Arp8 KO cells, the oxidative stress-induced expression of HMOX1 gene, encoding for heme oxygenase-1 (HO-1), was significantly impaired. Consistent with these observations, chromatin immunoprecipitation (ChIP) assay revealed that oxidative stress caused an increase in the binding of the INO80 complex to the regulatory sites of HMOX1 in wild-type cells. The binding of INO80 complex to chromatin was reduced in Arp8 KO cells compared to that in the wild-type cells. On the other hand, the binding of INO80 complex to chromatin in Arp5 KO cells was similar to that in the wild-type cells even under the oxidative stress condition. However, both remodeling of chromatin at the HMOX1 regulatory sites and binding of a transcriptional activator to these sites were impaired in Arp5 KO cells, indicating that Arp5 is required for the activation of the INO80 complex. Collectively, these results suggested that these nuclear Arps play indispensable roles in the function of the INO80 chromatin remodeling complex.
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Affiliation(s)
- Yuichiro Takahashi
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University Sendai, Japan
| | - Hirokazu Murakami
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University Sendai, Japan
| | - Yusuke Akiyama
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University Sendai, Japan
| | - Yasutake Katoh
- Department of Biochemistry, Graduate School of Medicine, Tohoku University Sendai, Japan
| | - Yukako Oma
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University Sendai, Japan
| | - Hitoshi Nishijima
- Department of Integrated Genetics, National Institute of GeneticsMishima, Japan; Division of Molecular Immunology, Institute of Advanced Medical Sciences, Tokushima UniversityTokushima, Japan
| | - Kei-Ichi Shibahara
- Department of Integrated Genetics, National Institute of Genetics Mishima, Japan
| | - Kazuhiko Igarashi
- Department of Biochemistry, Graduate School of Medicine, Tohoku UniversitySendai, Japan; Japan Agency for Medical Research and DevelopmentTokyo, Japan
| | - Masahiko Harata
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University Sendai, Japan
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20
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Willhoft O, Bythell-Douglas R, McCormack EA, Wigley DB. Synergy and antagonism in regulation of recombinant human INO80 chromatin remodeling complex. Nucleic Acids Res 2016; 44:8179-88. [PMID: 27257055 PMCID: PMC5041457 DOI: 10.1093/nar/gkw509] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 05/23/2016] [Indexed: 12/30/2022] Open
Abstract
We have purified a minimal core human Ino80 complex from recombinant protein expressed in insect cells. The complex comprises one subunit each of an N-terminally truncated Ino80, actin, Arp4, Arp5, Arp8, Ies2 and Ies6, together with a single heterohexamer of the Tip49a and Tip49b proteins. This core complex has nucleosome sliding activity that is similar to that of endogenous human and yeast Ino80 complexes and is also inhibited by inositol hexaphosphate (IP6). We show that IP6 is a non-competitive inhibitor that acts by blocking the stimulatory effect of nucleosomes on the ATPase activity. The IP6 binding site is located within the C-terminal region of the Ino80 subunit. We have also prepared complexes lacking combinations of Ies2 and Arp5/Ies6 subunits that reveal regulation imposed by each of them individually and synergistically that couples ATP hydrolysis to nucleosome sliding. This coupling between Ies2 and Arp5/Ies6 can be overcome in a bypass mutation of the Arp5 subunit that is active in the absence of Ies2. These studies reveal several underlying mechanisms for regulation of ATPase activity involving a complex interplay between these protein subunits and IP6 that in turn controls nucleosome sliding.
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Affiliation(s)
- Oliver Willhoft
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Rohan Bythell-Douglas
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Elizabeth A McCormack
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Dale B Wigley
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
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21
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Ewens CA, Su M, Zhao L, Nano N, Houry WA, Southworth DR. Architecture and Nucleotide-Dependent Conformational Changes of the Rvb1-Rvb2 AAA+ Complex Revealed by Cryoelectron Microscopy. Structure 2016; 24:657-666. [PMID: 27112599 DOI: 10.1016/j.str.2016.03.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 02/09/2016] [Accepted: 03/10/2016] [Indexed: 11/16/2022]
Abstract
Rvb1 and Rvb2 are essential AAA+ proteins that interact together during the assembly and activity of diverse macromolecules including chromatin remodelers INO80 and SWR-C, and ribonucleoprotein complexes including telomerase and snoRNPs. ATP hydrolysis by Rvb1/2 is required for function; however, the mechanism that drives substrate remodeling is unknown. Here we determined the architecture of the yeast Rvb1/2 dodecamer using cryoelectron microscopy and identify that the substrate-binding insertion domain undergoes conformational changes in response to nucleotide state. 2D and 3D classification defines the dodecamer flexibility, revealing distinct arrangements and the hexamer-hexamer interaction interface. Reconstructions of the apo, ATP, and ADP states identify that Rvb1/2 undergoes substantial conformational changes that include a twist in the insertion-domain position and a corresponding rotation of the AAA+ ring. These results reveal how the ATP hydrolysis cycle of the AAA+ domains directs insertion-domain movements that could provide mechanical force during remodeling or helicase activities.
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Affiliation(s)
- Caroline A Ewens
- Department of Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Min Su
- Department of Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Liang Zhao
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Nardin Nano
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Walid A Houry
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Daniel R Southworth
- Department of Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.
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22
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Actin, actin-binding proteins, and actin-related proteins in the nucleus. Histochem Cell Biol 2016; 145:373-88. [PMID: 26847179 DOI: 10.1007/s00418-015-1400-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2015] [Indexed: 10/25/2022]
Abstract
Extensive research in the past decade has significantly broadened our view about the role actin plays in the life of the cell and added novel aspects to actin research. One of these new aspects is the discovery of the existence of nuclear actin which became evident only recently. Nuclear activities including transcriptional activation in the case of all three RNA polymerases, editing and nuclear export of mRNAs, and chromatin remodeling all depend on actin. It also became clear that there is a fine-tuned equilibrium between cytoplasmic and nuclear actin pools and that this balance is ensured by an export-import system dedicated to actin. After over half a century of research on conventional actin and its organizing partners in the cytoplasm, it was also an unexpected finding that the nucleus contains more than 30 actin-binding proteins and new classes of actin-related proteins which are not able to form filaments but had evolved nuclear-specific functions. The actin-binding and actin-related proteins in the nucleus have been linked to RNA transcription and processing, nuclear transport, and chromatin remodeling. In this paper, we attempt to provide an overview of the wide range of information that is now available about actin, actin-binding, and actin-related proteins in the nucleus.
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23
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The INO80 Complex Requires the Arp5-Ies6 Subcomplex for Chromatin Remodeling and Metabolic Regulation. Mol Cell Biol 2016; 36:979-91. [PMID: 26755556 DOI: 10.1128/mcb.00801-15] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 12/30/2015] [Indexed: 11/20/2022] Open
Abstract
ATP-dependent chromatin remodeling complexes are essential for transcription regulation, and yet it is unclear how these multisubunit complexes coordinate their activities to facilitate diverse transcriptional responses. In this study, we found that the conserved Arp5 and Ies6 subunits of the Saccharomyces cerevisiae INO80 chromatin-remodeler form an abundant and distinct subcomplex in vivo and stimulate INO80-mediated activity in vitro. Moreover, our genomic studies reveal that the relative occupancy of Arp5-Ies6 correlates with nucleosome positioning at transcriptional start sites and expression levels of >1,000 INO80-regulated genes. Notably, these genes are significantly enriched in energy metabolism pathways. Specifically, arp5Δ, ies6Δ, and ino80Δ mutants demonstrate decreased expression of genes involved in glycolysis and increased expression of genes in the oxidative phosphorylation pathway. Deregulation of these metabolic pathways results in constitutively elevated mitochondrial potential and oxygen consumption. Our results illustrate the dynamic nature of the INO80 complex assembly and demonstrate for the first time that a chromatin remodeler regulates glycolytic and respiratory capacity, thereby maintaining metabolic stability.
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