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Jo SH, Park HJ, Lee A, Jung H, Park JM, Kwon SY, Kim HS, Lee HJ, Kim YS, Jung C, Cho HS. The Arabidopsis cyclophilin CYP18-1 facilitates PRP18 dephosphorylation and the splicing of introns retained under heat stress. THE PLANT CELL 2022; 34:2383-2403. [PMID: 35262729 PMCID: PMC9134067 DOI: 10.1093/plcell/koac084] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 03/05/2022] [Indexed: 05/13/2023]
Abstract
In plants, heat stress induces changes in alternative splicing, including intron retention; these events can rapidly alter proteins or downregulate protein activity, producing nonfunctional isoforms or inducing nonsense-mediated decay of messenger RNA (mRNA). Nuclear cyclophilins (CYPs) are accessory proteins in the spliceosome complexes of multicellular eukaryotes. However, whether plant CYPs are involved in pre-mRNA splicing remain unknown. Here, we found that Arabidopsis thaliana CYP18-1 is necessary for the efficient removal of introns that are retained in response to heat stress during germination. CYP18-1 interacts with Step II splicing factors (PRP18a, PRP22, and SWELLMAP1) and associates with the U2 and U5 small nuclear RNAs in response to heat stress. CYP18-1 binds to phospho-PRP18a, and increasing concentrations of CYP18-1 are associated with increasing dephosphorylation of PRP18a. Furthermore, interaction and protoplast transfection assays revealed that CYP18-1 and the PP2A-type phosphatase PP2A B'η co-regulate PRP18a dephosphorylation. RNA-seq and RT-qPCR analysis confirmed that CYP18-1 is essential for splicing introns that are retained under heat stress. Overall, we reveal the mechanism of action by which CYP18-1 activates the dephosphorylation of PRP18 and show that CYP18-1 is crucial for the efficient splicing of retained introns and rapid responses to heat stress in plants.
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Affiliation(s)
- Seung Hee Jo
- Plant Systems Engineering Research Center, Korea Research Institute of
Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology,
Korea University of Science and Technology, Daejeon 34113, Korea
| | - Hyun Ji Park
- Plant Systems Engineering Research Center, Korea Research Institute of
Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
| | - Areum Lee
- Plant Systems Engineering Research Center, Korea Research Institute of
Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology,
Korea University of Science and Technology, Daejeon 34113, Korea
| | - Haemyeong Jung
- Plant Systems Engineering Research Center, Korea Research Institute of
Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology,
Korea University of Science and Technology, Daejeon 34113, Korea
| | - Jeong Mee Park
- Plant Systems Engineering Research Center, Korea Research Institute of
Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
| | - Suk-Yoon Kwon
- Plant Systems Engineering Research Center, Korea Research Institute of
Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
| | - Hyun-Soon Kim
- Plant Systems Engineering Research Center, Korea Research Institute of
Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
| | - Hyo-Jun Lee
- Plant Systems Engineering Research Center, Korea Research Institute of
Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
- Department of Functional Genomics, KRIBB School of Bioscience, University
of Science and Technology, Daejeon 34113, Korea
| | - Youn-Sung Kim
- Department of Biotechnology, NongWoo
Bio, Anseong 17558, Korea
| | - Choonkyun Jung
- Department of International Agricultural Technology and Crop Biotechnology
Institute/Green Bio Science and Technology, Seoul National University,
Pyeongchang 25354, Korea
- Department of Agriculture, Forestry, and Bioresources and Integrated Major
in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National
University, Seoul 08826, Korea
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2
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Dilworth D, Upadhyay SK, Bonnafous P, Edoo AB, Bourbigot S, Pesek-Jardim F, Gudavicius G, Serpa JJ, Petrotchenko EV, Borchers CH, Nelson CJ, Mackereth CD. The basic tilted helix bundle domain of the prolyl isomerase FKBP25 is a novel double-stranded RNA binding module. Nucleic Acids Res 2017; 45:11989-12004. [PMID: 29036638 PMCID: PMC5714180 DOI: 10.1093/nar/gkx852] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 09/13/2017] [Indexed: 11/14/2022] Open
Abstract
Prolyl isomerases are defined by a catalytic domain that facilitates the cis–trans interconversion of proline residues. In most cases, additional domains in these enzymes add important biological function, including recruitment to a set of protein substrates. Here, we report that the N-terminal basic tilted helix bundle (BTHB) domain of the human prolyl isomerase FKBP25 confers specific binding to double-stranded RNA (dsRNA). This binding is selective over DNA as well as single-stranded oligonucleotides. We find that FKBP25 RNA-association is required for its nucleolar localization and for the vast majority of its protein interactions, including those with 60S pre-ribosome and early ribosome biogenesis factors. An independent mobility of the BTHB and FKBP catalytic domains supports a model by which the N-terminus of FKBP25 is anchored to regions of dsRNA, whereas the FKBP domain is free to interact with neighboring proteins. Apart from the identification of the BTHB as a new dsRNA-binding module, this domain adds to the growing list of auxiliary functions used by prolyl isomerases to define their primary cellular targets.
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Affiliation(s)
- David Dilworth
- Dept. of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
| | - Santosh K Upadhyay
- Univ. Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France.,Inserm U1212, CNRS UMR 5320, ARNA Laboratory, Univ. Bordeaux, 146 rue Léo Saignat, F-33076 Bordeaux, France.,CSIR-Institute of Genomics and Integrative Biology, New Delhi 110020, India
| | - Pierre Bonnafous
- Univ. Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France.,Inserm U1212, CNRS UMR 5320, ARNA Laboratory, Univ. Bordeaux, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Amiirah Bibi Edoo
- Univ. Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France.,Inserm U1212, CNRS UMR 5320, ARNA Laboratory, Univ. Bordeaux, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Sarah Bourbigot
- Univ. Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France.,Inserm U1212, CNRS UMR 5320, ARNA Laboratory, Univ. Bordeaux, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Francy Pesek-Jardim
- Dept. of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
| | - Geoff Gudavicius
- Dept. of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
| | - Jason J Serpa
- Dept. of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada.,University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, BC V8Z 7X8, Canada
| | - Evgeniy V Petrotchenko
- Dept. of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada.,University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, BC V8Z 7X8, Canada
| | - Christoph H Borchers
- Dept. of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada.,University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, BC V8Z 7X8, Canada
| | - Christopher J Nelson
- Dept. of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
| | - Cameron D Mackereth
- Univ. Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France.,Inserm U1212, CNRS UMR 5320, ARNA Laboratory, Univ. Bordeaux, 146 rue Léo Saignat, F-33076 Bordeaux, France
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3
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Castello A, Fischer B, Frese CK, Horos R, Alleaume AM, Foehr S, Curk T, Krijgsveld J, Hentze MW. Comprehensive Identification of RNA-Binding Domains in Human Cells. Mol Cell 2016; 63:696-710. [PMID: 27453046 PMCID: PMC5003815 DOI: 10.1016/j.molcel.2016.06.029] [Citation(s) in RCA: 389] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 05/31/2016] [Accepted: 06/20/2016] [Indexed: 12/18/2022]
Abstract
Mammalian cells harbor more than a thousand RNA-binding proteins (RBPs), with half of these employing unknown modes of RNA binding. We developed RBDmap to determine the RNA-binding sites of native RBPs on a proteome-wide scale. We identified 1,174 binding sites within 529 HeLa cell RBPs, discovering numerous RNA-binding domains (RBDs). Catalytic centers or protein-protein interaction domains are in close relationship with RNA-binding sites, invoking possible effector roles of RNA in the control of protein function. Nearly half of the RNA-binding sites map to intrinsically disordered regions, uncovering unstructured domains as prevalent partners in protein-RNA interactions. RNA-binding sites represent hot spots for defined posttranslational modifications such as lysine acetylation and tyrosine phosphorylation, suggesting metabolic and signal-dependent regulation of RBP function. RBDs display a high degree of evolutionary conservation and incidence of Mendelian mutations, suggestive of important functional roles. RBDmap thus yields profound insights into native protein-RNA interactions in living cells.
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Affiliation(s)
- Alfredo Castello
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany; Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Bernd Fischer
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany; German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Christian K Frese
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Rastislav Horos
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Anne-Marie Alleaume
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Sophia Foehr
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Tomaz Curk
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany; Faculty of Computer and Information Science, University of Ljubljana, 1001 Ljubljana, Slovenia
| | - Jeroen Krijgsveld
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany; German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Matthias W Hentze
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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Lee SS, Park HJ, Jung WY, Lee A, Yoon DH, You YN, Kim HS, Kim BG, Ahn JC, Cho HS. OsCYP21-4, a novel Golgi-resident cyclophilin, increases oxidative stress tolerance in rice. FRONTIERS IN PLANT SCIENCE 2015; 6:797. [PMID: 26483814 PMCID: PMC4589654 DOI: 10.3389/fpls.2015.00797] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 09/13/2015] [Indexed: 05/20/2023]
Abstract
OsCYP21-4 is a rice cyclophilin protein that binds to cyclosporine A, an immunosuppressant drug. CYP21-4s in Arabidopsis and rice were previously shown to function as mitochondrial cyclophilins, as determined by TargetP analysis. In the current study, we found that OsCYP21-4-GFP localized to the Golgi, rather than mitochondria, in Nicotiana benthamiana leaves, which was confirmed based on its co-localization with cis Golgi α-ManI-mCherry protein. OsCYP21-4 transcript levels increased in response to treatments with various abiotic stresses and the phytohormone abscisic acid, revealing its stress-responsiveness. CYP21-4 homologs do not possess key peptidyl prolyl cis/trans isomerase (PPIase) activity/cyclosporine A (CsA) binding residues, and recombinant OsCYP21-4 protein did not convert the synthetic substrate Suc-AAPF-pNA via cis- trans- isomerization in vitro. In addition, transgenic plants overexpressing OsCYP21-4 exhibited increased tolerance to salinity and hydrogen peroxide treatment, along with increased peroxidase activity. These results demonstrate that OsCYP21-4 is a novel Golgi-localized cyclophilin that plays a role in oxidative stress tolerance, possibly by regulating peroxidase activity.
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Affiliation(s)
- Sang S. Lee
- Sustainable Bioresource Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, South Korea
| | - Hyun J. Park
- Sustainable Bioresource Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, South Korea
| | - Won Y. Jung
- Sustainable Bioresource Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, South Korea
| | - Areum Lee
- Sustainable Bioresource Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, South Korea
| | - Dae H. Yoon
- Sustainable Bioresource Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, South Korea
| | - Young N. You
- Sustainable Bioresource Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, South Korea
| | - Hyun-Soon Kim
- Sustainable Bioresource Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, South Korea
| | - Beom-Gi Kim
- Molecular Breeding Division, National Academy of Agricultural Science, Rural Development of AgricultureJeonju, South Korea
| | - Jun C. Ahn
- Department of Pharmacology, College of Medicine, Seonam UniversityNamwon, South Korea
| | - Hye S. Cho
- Sustainable Bioresource Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, South Korea
- *Correspondence: Hye S. Cho, Sustainable Bioresource Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 305-806, South Korea
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5
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Ulrich A, Wahl MC. Structure and evolution of the spliceosomal peptidyl-prolyl cis-trans isomerase Cwc27. ACTA ACUST UNITED AC 2014; 70:3110-23. [PMID: 25478830 DOI: 10.1107/s1399004714021695] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 10/01/2014] [Indexed: 11/10/2022]
Abstract
Cwc27 is a spliceosomal cyclophilin-type peptidyl-prolyl cis-trans isomerase (PPIase). Here, the crystal structure of a relatively protease-resistant N-terminal fragment of human Cwc27 containing the PPIase domain was determined at 2.0 Å resolution. The fragment exhibits a C-terminal appendix and resides in a reduced state compared with the previous oxidized structure of a similar fragment. By combining multiple sequence alignments spanning the eukaryotic tree of life and secondary-structure prediction, Cwc27 proteins across the entire eukaryotic kingdom were identified. This analysis revealed the specific loss of a crucial active-site residue in higher eukaryotic Cwc27 proteins, suggesting that the protein evolved from a prolyl isomerase to a pure proline binder. Noting a fungus-specific insertion in the PPIase domain, the 1.3 Å resolution crystal structure of the PPIase domain of Cwc27 from Chaetomium thermophilum was also determined. Although structurally highly similar in the core domain, the C. thermophilum protein displayed a higher thermal stability than its human counterpart, presumably owing to the combined effect of several amino-acid exchanges that reduce the number of long side chains with strained conformations and create new intramolecular interactions, in particular increased hydrogen-bond networks.
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Affiliation(s)
- Alexander Ulrich
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Markus C Wahl
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
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6
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Hanes SD. Prolyl isomerases in gene transcription. Biochim Biophys Acta Gen Subj 2014; 1850:2017-34. [PMID: 25450176 DOI: 10.1016/j.bbagen.2014.10.028] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 10/20/2014] [Accepted: 10/23/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND Peptidyl-prolyl isomerases (PPIases) are enzymes that assist in the folding of newly-synthesized proteins and regulate the stability, localization, and activity of mature proteins. They do so by catalyzing reversible (cis-trans) rotation about the peptide bond that precedes proline, inducing conformational changes in target proteins. SCOPE OF REVIEW This review will discuss how PPIases regulate gene transcription by controlling the activity of (1) DNA-binding transcription regulatory proteins, (2) RNA polymerase II, and (3) chromatin and histone modifying enzymes. MAJOR CONCLUSIONS Members of each family of PPIase (cyclophilins, FKBPs, and parvulins) regulate gene transcription at multiple levels. In all but a few cases, the exact mechanisms remain elusive. Structure studies, development of specific inhibitors, and new methodologies for studying cis/trans isomerization in vivo represent some of the challenges in this new frontier that merges two important fields. GENERAL SIGNIFICANCE Prolyl isomerases have been found to play key regulatory roles in all phases of the transcription process. Moreover, PPIases control upstream signaling pathways that regulate gene-specific transcription during development, hormone response and environmental stress. Although transcription is often rate-limiting in the production of enzymes and structural proteins, post-transcriptional modifications are also critical, and PPIases play key roles here as well (see other reviews in this issue). This article is part of a Special Issue entitled Proline-directed Foldases: Cell Signaling Catalysts and Drug Targets.
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Affiliation(s)
- Steven D Hanes
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, 750 E Adams St., Syracuse, NY 13210 USA.
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7
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Mesa A, Somarelli JA, Wu W, Martinez L, Blom MB, Greidinger EL, Herrera RJ. Differential immunoglobulin class-mediated responses to components of the U1 small nuclear ribonucleoprotein particle in systemic lupus erythematosus and mixed connective tissue disease. Lupus 2014; 22:1371-81. [PMID: 24158973 DOI: 10.1177/0961203313508444] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The objective of this paper is to determine whether patients with systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) possess differential IgM- and IgG-specific reactivity against peptides from the U1 small nuclear ribonucleoprotein particle (U1 snRNP). METHODS The IgM- and IgG-mediated responses against 15 peptides from subunits of the U1 snRNP were assessed by indirect enzyme linked immunosorbent assays (ELISAs) in sera from patients with SLE and MCTD and healthy individuals (n = 81, 41, and 31, respectively). Additionally, 42 laboratory tests and 40 clinical symptoms were evaluated to uncover potential differences. Binomial logistic regression analyses (BLR) were performed to construct models to support the independent nature of SLE and MCTD. Receiver operating characteristic (ROC) curves corroborated the classification power of the models. RESULTS We analyzed IgM and IgG anti-U1 snRNP titers to classify SLE and MCTD patients. IgG anti-U1 snRNP reactivity segregates SLE and MCTD from nondisease controls with an accuracy of 94.1% while IgM-specific anti-U1 snRNP responses distinguish SLE from MCTD patients with an accuracy of 71.3%. Comparison of the IgG and IgM anti-U1 snRNP approach with clinical tests used for diagnosing SLE and MCTD revealed that our method is the best classification tool of those analyzed (p ≤ 0.0001). CONCLUSIONS Our IgM anti-U1 snRNP system along with lab tests and symptoms provide additional molecular and clinical evidence to support the hypothesis that SLE and MCTD may be distinct syndromes.
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Affiliation(s)
- A Mesa
- 1Department of Biological Sciences, Florida International University, USA
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8
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Cyclophilins as modulators of viral replication. Viruses 2013; 5:1684-701. [PMID: 23852270 PMCID: PMC3738956 DOI: 10.3390/v5071684] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 06/26/2013] [Accepted: 07/03/2013] [Indexed: 01/11/2023] Open
Abstract
Cyclophilins are peptidyl‐prolyl cis/trans isomerases important in the proper folding of certain proteins. Mounting evidence supports varied roles of cyclophilins, either positive or negative, in the life cycles of diverse viruses, but the nature and mechanisms of these roles are yet to be defined. The potential for cyclophilins to serve as a drug target for antiviral therapy is evidenced by the success of non-immunosuppressive cyclophilin inhibitors (CPIs), including Alisporivir, in clinical trials targeting hepatitis C virus infection. In addition, as cyclophilins are implicated in the predisposition to, or severity of, various diseases, the ability to specifically and effectively modulate their function will prove increasingly useful for disease intervention. In this review, we will summarize the evidence of cyclophilins as key mediators of viral infection and prospective drug targets.
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9
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Baugh J, Gallay P. Cyclophilin involvement in the replication of hepatitis C virus and other viruses. Biol Chem 2013; 393:579-87. [PMID: 22944661 DOI: 10.1515/hsz-2012-0151] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 04/10/2012] [Indexed: 02/07/2023]
Abstract
In recent months, there has been a wealth of promising clinical data suggesting that a more effective treatment regimen, and potentially a cure, for hepatitis C virus (HCV) infection is close at hand. Leading this push are direct-acting antivirals (DAAs), currently comprising inhibitors that target the HCV protease NS3, the viral polymerase NS5B, and the non-structural protein NS5A. In combination with one another, along with the traditional standard-of-care ribavirin and PEGylated-IFNα, these compounds have proven to afford tremendous efficacy to treatment-naíve patients, as well as to prior non-responders. Nevertheless, by targeting viral components, the possibility of selecting for breakthrough and treatment-resistant virus strains remains a concern. Host-targeting antivirals are a distinct class of anti-HCV compounds that is emerging as a complementary set of tools to combat the disease. Cyclophilin (Cyp) inhibitors are one such group in this category. In contrast to DAAs, Cyp inhibitors target a host protein, CypA, and have also demonstrated remarkable antiviral efficiency in clinical trials, without the generation of viral escape mutants. This review serves to summarize the current literature on Cyps and their relation to the HCV viral life cycle, as well as other viruses.
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Affiliation(s)
- James Baugh
- Department of Immunology and Microbial Science, IMM-9, The Scripps Research Institute, La Jolla, CA 92037, USA
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10
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Castello A, Fischer B, Eichelbaum K, Horos R, Beckmann BM, Strein C, Davey NE, Humphreys DT, Preiss T, Steinmetz LM, Krijgsveld J, Hentze MW. Insights into RNA biology from an atlas of mammalian mRNA-binding proteins. Cell 2012; 149:1393-406. [PMID: 22658674 DOI: 10.1016/j.cell.2012.04.031] [Citation(s) in RCA: 1514] [Impact Index Per Article: 126.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 03/08/2012] [Accepted: 04/24/2012] [Indexed: 10/28/2022]
Abstract
RNA-binding proteins (RBPs) determine RNA fate from synthesis to decay. Employing two complementary protocols for covalent UV crosslinking of RBPs to RNA, we describe a systematic, unbiased, and comprehensive approach, termed "interactome capture," to define the mRNA interactome of proliferating human HeLa cells. We identify 860 proteins that qualify as RBPs by biochemical and statistical criteria, adding more than 300 RBPs to those previously known and shedding light on RBPs in disease, RNA-binding enzymes of intermediary metabolism, RNA-binding kinases, and RNA-binding architectures. Unexpectedly, we find that many proteins of the HeLa mRNA interactome are highly intrinsically disordered and enriched in short repetitive amino acid motifs. Interactome capture is broadly applicable to study mRNA interactome composition and dynamics in varied biological settings.
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11
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Horowitz DS. The mechanism of the second step of pre-mRNA splicing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 3:331-50. [PMID: 22012849 DOI: 10.1002/wrna.112] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The molecular mechanisms of the second step of pre-mRNA splicing in yeast and higher eukaryotes are reviewed. The important elements in the pre-mRNA, the participating proteins, and the proposed secondary structures and roles of the snRNAs are described. The sequence of events in the second step is presented, focusing on the actions of the proteins in setting up and facilitating the second reaction. Mechanisms for avoiding errors in splicing are discussed.
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Affiliation(s)
- David S Horowitz
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
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12
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Dilworth D, Gudavicius G, Leung A, Nelson CJ. The roles of peptidyl-proline isomerases in gene regulation. Biochem Cell Biol 2011; 90:55-69. [PMID: 21999350 DOI: 10.1139/o11-045] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The post-translational modification of proteins and enzymes provides a dynamic and reversible means to control protein function and transmit biological signals. While covalent modifications such as phosphorylation and acetylation have drawn much attention, in the past decade the involvement of peptidyl-proline isomerases (PPIs) in signaling and post-translational modification of protein function has become increasingly apparent. Three distinct families of PPI enzymes (parvulins, cyclophilins, and FK506-binding proteins (FKBPs)) each have the capacity to catalyze cis-trans proline isomerization in substrate proteins, and this modification can regulate both structure and function. In eukaryotic cells, a subset of these enzymes is localized to the nucleus, where they regulate gene expression at multiple control points. Here we summarize this body of work that together establishes a clear role of these enzymes as evolutionarily conserved players in the control of both transcription of mRNAs and the assembly of chromatin.
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Affiliation(s)
- David Dilworth
- The Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
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13
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Somarelli JA, Mesa A, Fuller ME, Torres JO, Rodriguez CE, Ferrer CM, Herrera RJ. Genome-based identification of spliceosomal proteins in the silk moth Bombyx mori. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2010; 75:231-263. [PMID: 21104883 DOI: 10.1002/arch.20390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Pre-messenger RNA splicing is a highly conserved eukaryotic cellular function that takes place by way of a large, RNA-protein assembly known as the spliceosome. In the mammalian system, nearly 300 proteins associate with uridine-rich small nuclear (sn)RNAs to form this complex. Some of these splicing factors are ubiquitously present in the spliceosome, whereas others are involved only in the processing of specific transcripts. Several proteomics analyses have delineated the proteins of the spliceosome in several species. In this study, we mine multiple sequence data sets of the silk moth Bombyx mori in an attempt to identify the entire set of known spliceosomal proteins. Five data sets were utilized, including the 3X, 6X, and Build 2.0 genomic contigs as well as the expressed sequence tag and protein libraries. While homologs for 88% of vertebrate splicing factors were delineated in the Bombyx mori genome, there appear to be several spliceosomal polypeptides absent in Bombyx mori and seven additional insect species. This apparent increase in spliceosomal complexity in vertebrates may reflect the tissue-specific and developmental stage-specific alternative pre-mRNA splicing requirements in vertebrates. Phylogenetic analyses of 15 eukaryotic taxa using the core splicing factors suggest that the essential functional units of the pre-mRNA processing machinery have remained highly conserved from yeast to humans. The Sm and LSm proteins are the most conserved, whereas proteins of the U1 small nuclear ribonucleoprotein particle are the most divergent. These data highlight both the differential conservation and relative phylogenetic signals of the essential spliceosomal components throughout evolution.
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Affiliation(s)
- Jason A Somarelli
- Department of Biological Sciences, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
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Goldstone DC, Yap MW, Robertson LE, Haire LF, Taylor WR, Katzourakis A, Stoye JP, Taylor IA. Structural and Functional Analysis of Prehistoric Lentiviruses Uncovers an Ancient Molecular Interface. Cell Host Microbe 2010; 8:248-59. [DOI: 10.1016/j.chom.2010.08.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 06/11/2010] [Accepted: 06/30/2010] [Indexed: 11/17/2022]
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15
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Stegmann CM, Lührmann R, Wahl MC. The crystal structure of PPIL1 bound to cyclosporine A suggests a binding mode for a linear epitope of the SKIP protein. PLoS One 2010; 5:e10013. [PMID: 20368803 PMCID: PMC2848857 DOI: 10.1371/journal.pone.0010013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 03/08/2010] [Indexed: 12/02/2022] Open
Abstract
Background The removal of introns from pre-mRNA is carried out by a large macromolecular machine called the spliceosome. The peptidyl-prolyl cis/trans isomerase PPIL1 is a component of the human spliceosome and binds to the spliceosomal SKIP protein via a binding site distinct from its active site. Principal Findings Here, we have studied the PPIL1 protein and its interaction with SKIP biochemically and by X-ray crystallography. A minimal linear binding epitope derived from the SKIP protein could be determined using a peptide array. A 36-residue region of SKIP centred on an eight-residue epitope suffices to bind PPIL1 in pull-down experiments. The crystal structure of PPIL1 in complex with the inhibitor cyclosporine A (CsA) was obtained at a resolution of 1.15 Å and exhibited two bound Cd2+ ions that enabled SAD phasing. PPIL1 residues that have previously been implicated in binding of SKIP are involved in the coordination of Cd2+ ions in the present crystal structure. Employing the present crystal structure, the determined minimal binding epitope and previously published NMR data [1], a molecular docking study was performed. In the docked model of the PPIL1·SKIP interaction, a proline residue of SKIP is buried in a hydrophobic pocket of PPIL1. This hydrophobic contact is encircled by several hydrogen bonds between the SKIP peptide and PPIL1. Conclusion We characterized a short, linear epitope of SKIP that is sufficient to bind the PPIL1 protein. Our data indicate that this SKIP peptide could function in recruiting PPIL1 into the core of the spliceosome. We present a molecular model for the binding mode of SKIP to PPIL1 which emphasizes the versatility of cyclophilin-type PPIases to engage in additional interactions with other proteins apart from active site contacts despite their limited surface area.
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Affiliation(s)
- Christian M. Stegmann
- Max-Planck-Institut für biophysikalische Chemie, Zelluläre Biochemie/Makromolekulare Röntgenkristallographie, Göttingen, Germany
- Max-Planck-Institut für biophysikalische Chemie, AG Strukturbiochemie, Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Reinhard Lührmann
- Max-Planck-Institut für biophysikalische Chemie, Zelluläre Biochemie/Makromolekulare Röntgenkristallographie, Göttingen, Germany
| | - Markus C. Wahl
- Max-Planck-Institut für biophysikalische Chemie, Zelluläre Biochemie/Makromolekulare Röntgenkristallographie, Göttingen, Germany
- Max-Planck-Institut für biophysikalische Chemie, AG Strukturbiochemie, Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
- * E-mail:
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16
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Wang X, Zhang S, Zhang J, Huang X, Xu C, Wang W, Liu Z, Wu J, Shi Y. A large intrinsically disordered region in SKIP and its disorder-order transition induced by PPIL1 binding revealed by NMR. J Biol Chem 2009; 285:4951-63. [PMID: 20007319 DOI: 10.1074/jbc.m109.087528] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Intrinsically disordered proteins or protein regions play an important role in fundamental biological processes. During spliceosome activation, a large structural rearrangement occurs. The Prp19 complex and related factors are involved in the catalytic activation of the spliceosome. Recent mass spectrometric analyses have shown that Ski interaction protein (SKIP) and peptidylprolyl isomerase-like protein 1 (PPIL1) are Prp19-related factors that constitute the spliceosome B, B*, and C complexes. Here, we report that a highly flexible region of SKIP (SKIPN, residues 59-129) is intrinsically disordered. Upon binding to PPIL1, SKIPN undergoes a disorder-order transition. A highly conserved fragment of SKIP (residues 59-79) called the PPIL1-binding fragment (PBF) was sufficient to bind PPIL1. The structure of PBF.PPIL1 complex, solved by NMR, shows that PBF exhibits an ordered structure and interacts with PPIL1 through electrostatic and hydrophobic interactions. Three subfragments in the PBF (residues 59-67, 68-73, and 74-79) show hook-like backbone structure, and interactions between these subfragments are necessary for PBF.PPIL1 complex formation. PPIL1 is a cyclophilin family protein. It is recruited by SKIP into the spliceosome by a region other than the peptidylprolyl isomerase active site. This enables the active site of PPIL1 to remain open in the complex and still function as a peptidylprolyl cis/trans-isomerase or molecular chaperon to facilitate the folding of other proteins in the spliceosomes. The large disordered region in SKIP provides an interaction platform. Its disorder-order transition, induced by PPIL1 binding, may adapt the requirement for a large structural rearrangement occurred in the activation of spliceosome.
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Affiliation(s)
- Xingsheng Wang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
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17
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Krücken J, Greif G, von Samson-Himmelstjerna G. In silico analysis of the cyclophilin repertoire of apicomplexan parasites. Parasit Vectors 2009; 2:27. [PMID: 19555495 PMCID: PMC2713222 DOI: 10.1186/1756-3305-2-27] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 06/25/2009] [Indexed: 11/26/2022] Open
Abstract
Background Cyclophilins (Cyps) are peptidyl cis/trans isomerases implicated in diverse processes such as protein folding, signal transduction, and RNA processing. They are also candidate drug targets, in particular for the immunosuppressant cyclosporine A. In addition, cyclosporine is known to exhibit anti-parasitic effects on a wide range of organisms including several apicomplexa. In order to obtain new non-immunosuppressive drugs targeting apicomplexan cyclophilins, a profound knowledge of the cyclophilin repertoire of this phylum would be necessary. Results BLAST and maximum likelihood analyses identified 16 different cyclophilin subfamilies within the genomes of Cryptosporidium hominis, Toxoplasma gondii, Plasmodium falciparum, Theileria annulata, Theileria parva, and Babesia bovis. In addition to good statistical support from the phylogenetic analysis, these subfamilies are also confirmed by comparison of cyclophilin domain architecture. Within an individual genome, the number of different Cyp genes that could be deduced varies between 7–9 for Cryptosporidia and 14 for T. gondii. Many of the putative apicomplexan cyclophilins are predicted to be nuclear proteins, most of them presumably involved in RNA processing. Conclusion The genomes of apicomplexa harbor a cyclophilin repertoire that is at least as complex as that of most fungi. The identification of Cyp subfamilies that are specific for lower eukaryotes, apicomplexa, or even the genus Plasmodium is of particular interest since these subfamilies are not present in host cells and might therefore represent attractive drug targets.
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Affiliation(s)
- Jürgen Krücken
- Institute for Parasitology, University of Veterinary Medicine Foundation, Bünteweg 17, 30559 Hannover, Germany.
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