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Miller WE, O'Connor CM. CMV-encoded GPCRs in infection, disease, and pathogenesis. Adv Virus Res 2024; 118:1-75. [PMID: 38461029 DOI: 10.1016/bs.aivir.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2024]
Abstract
G protein coupled receptors (GPCRs) are seven-transmembrane domain proteins that modulate cellular processes in response to external stimuli. These receptors represent the largest family of membrane proteins, and in mammals, their signaling regulates important physiological functions, such as vision, taste, and olfaction. Many organisms, including yeast, slime molds, and viruses encode GPCRs. Cytomegaloviruses (CMVs) are large, betaherpesviruses, that encode viral GPCRs (vGPCRs). Human CMV (HCMV) encodes four vGPCRs, including UL33, UL78, US27, and US28. Each of these vGPCRs, as well as their rodent and primate orthologues, have been investigated for their contributions to viral infection and disease. Herein, we discuss how the CMV vGPCRs function during lytic and latent infection, as well as our understanding of how they impact viral pathogenesis.
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Affiliation(s)
- William E Miller
- Department of Molecular and Cellular Bioscience, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Christine M O'Connor
- Infection Biology, Sheikha Fatima bint Mubarak Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States; Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, OH, United States; Case Comprehensive Cancer Center, Cleveland, OH, United States.
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Smith NA, Chan GC, O’Connor CM. Modulation of host cell signaling during cytomegalovirus latency and reactivation. Virol J 2021. [DOI: 10.1186/s12985-021-01674-1
expr 947873540 + 978833141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
AbstractBackgroundHuman cytomegalovirus (HCMV) resides latently in cells of the myeloid compartment, including CD34+hematopoietic progenitor cells and circulating monocytes. Healthy hosts maintain the virus latently, and this infection is, for the most part, asymptomatic. However, given the proper external cues, HCMV reactivates from latency, at which point the virus disseminates, causing disease. The viral and cellular factors dictating the balance between these phases of infection are incompletely understood, though a large body of literature support a role for viral-mediated manipulation of host cell signaling.Main bodyTo establish and maintain latency, HCMV has evolved various means by which it usurps host cell factors to alter the cellular environment to its own advantage, including altering host cell signaling cascades. As early as virus entry into myeloid cells, HCMV usurps cellular signaling to change the cellular milieu, and this regulation includes upregulation, as well as downregulation, of different signaling cascades. Indeed, given proper reactivation cues, this signaling is again altered to allow for transactivation of viral lytic genes.ConclusionsHCMV modulation of host cell signaling is not binary, and many of the cellular pathways altered are finely regulated, wherein the slightest modification imparts profound changes to the cellular milieu. It is also evident that viral-mediated cell signaling differs not only between these phases of infection, but also is myeloid cell type specific. Nonetheless, understanding the exact pathways and the means by which HCMV mediates them will undoubtedly provide novel targets for therapeutic intervention.
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Modulation of host cell signaling during cytomegalovirus latency and reactivation. Virol J 2021; 18:207. [PMID: 34663377 PMCID: PMC8524946 DOI: 10.1186/s12985-021-01674-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 09/30/2021] [Indexed: 12/15/2022] Open
Abstract
Background Human cytomegalovirus (HCMV) resides latently in cells of the myeloid compartment, including CD34+ hematopoietic progenitor cells and circulating monocytes. Healthy hosts maintain the virus latently, and this infection is, for the most part, asymptomatic. However, given the proper external cues, HCMV reactivates from latency, at which point the virus disseminates, causing disease. The viral and cellular factors dictating the balance between these phases of infection are incompletely understood, though a large body of literature support a role for viral-mediated manipulation of host cell signaling. Main body To establish and maintain latency, HCMV has evolved various means by which it usurps host cell factors to alter the cellular environment to its own advantage, including altering host cell signaling cascades. As early as virus entry into myeloid cells, HCMV usurps cellular signaling to change the cellular milieu, and this regulation includes upregulation, as well as downregulation, of different signaling cascades. Indeed, given proper reactivation cues, this signaling is again altered to allow for transactivation of viral lytic genes. Conclusions HCMV modulation of host cell signaling is not binary, and many of the cellular pathways altered are finely regulated, wherein the slightest modification imparts profound changes to the cellular milieu. It is also evident that viral-mediated cell signaling differs not only between these phases of infection, but also is myeloid cell type specific. Nonetheless, understanding the exact pathways and the means by which HCMV mediates them will undoubtedly provide novel targets for therapeutic intervention.
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Singha M, Spitalny L, Nguyen K, Vandewalle A, Spitale RC. Chemical methods for measuring RNA expression with metabolic labeling. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1650. [PMID: 33738981 DOI: 10.1002/wrna.1650] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 12/27/2022]
Abstract
Tracking the expression of RNA in a cell-specific manner is a major challenge in basic and disease research. Herein we outline the current state of employing chemical approaches for cell-specific RNA expression studies. We define the utility of metabolic labels for tracking RNA synthesis, the approaches for characterizing metabolic incorporation and enrichment of labeled RNAs, and finally outline how these approaches have been used to study biological systems by providing mechanistic insights into transcriptional dynamics. Further efforts on this front will be the continued development of novel chemical handles for RNA enrichment and profiling as well as innovative approaches to control cell-specific incorporation of chemically modified metabolic probes. These advancements in RNA metabolic labeling techniques permit sensitive detection of RNA expression dynamics within relatively small subsets of cells in living tissues and organisms that are critical to performing complex developmental and pathological processes. This article is categorized under: RNA Methods > RNA Analyses in Cells RNA Evolution and Genomics > Ribonomics RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry.
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Affiliation(s)
- Monika Singha
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, California, USA
| | - Leslie Spitalny
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, California, USA
| | - Kim Nguyen
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, California, USA
| | - Abigail Vandewalle
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, California, USA
| | - Robert C Spitale
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, California, USA.,Department of Developmental and Cellular Biology, University of California, Irvine, Irvine, California, USA.,Department of Chemistry, University of California, Irvine, Irvine, California, USA
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Activator protein-1 transactivation of the major immediate early locus is a determinant of cytomegalovirus reactivation from latency. Proc Natl Acad Sci U S A 2020; 117:20860-20867. [PMID: 32788362 DOI: 10.1073/pnas.2009420117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous pathogen that latently infects hematopoietic cells and has the ability to reactivate when triggered by immunological stress. This reactivation causes significant morbidity and mortality in immune-deficient patients, who are unable to control viral dissemination. While a competent immune system helps prevent clinically detectable viremia, a portrait of the factors that induce reactivation following the proper cues remains incomplete. Our understanding of the complex molecular mechanisms underlying latency and reactivation continues to evolve. We previously showed the HCMV-encoded G protein-coupled receptor US28 is expressed during latency and facilitates latent infection by attenuating the activator protein-1 (AP-1) transcription factor subunit, c-fos, expression and activity. We now show AP-1 is a critical component for HCMV reactivation. Pharmacological inhibition of c-fos significantly attenuates viral reactivation. In agreement, infection with a virus in which we disrupted the proximal AP-1 binding site in the major immediate early (MIE) enhancer results in inefficient reactivation compared to WT. Concomitantly, AP-1 recruitment to the MIE enhancer is significantly decreased following reactivation of the mutant virus. Furthermore, AP-1 is critical for derepression of MIE-driven transcripts and downstream early and late genes, while immediate early genes from other loci remain unaffected. Our data also reveal MIE transcripts driven from the MIE promoter, the distal promoter, and the internal promoter, iP2, are dependent upon AP-1 recruitment, while iP1-driven transcripts are AP-1-independent. Collectively, our data demonstrate AP-1 binding to and activation of the MIE enhancer is a key molecular process controlling reactivation from latency.
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Poole E, Sinclair J. Understanding HCMV Latency Using Unbiased Proteomic Analyses. Pathogens 2020; 9:E590. [PMID: 32698381 PMCID: PMC7399836 DOI: 10.3390/pathogens9070590] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 02/07/2023] Open
Abstract
Human cytomegalovirus (HCMV) establishes either a latent (non-productive) or lytic (productive) infection depending upon cell type, cytokine milieu and the differentiation status of the infected cell. Undifferentiated cells, such as precursor cells of the myeloid lineage, support a latent infection whereas terminally differentiated cells, such as monocytes or dendritic cells are an environment conducive to reactivation and support a lytic infection. The mechanisms which regulate HCMV in either a latent or lytic infection have been the focus of intense investigation with a view to developing novel treatments for HCMV-associated disease which can have a heavy clinical burden after reactivation or primary infection in, especially, the immune compromised. To this end, a number of studies have been carried out in an unbiased manner to address global changes occurring within the latently infected cell to address the molecular changes associated with HCMV latency. In this review, we will concentrate on the proteomic analyses which have been carried out in undifferentiated myeloid cells which either stably express specific viral latency associated genes in isolation or on cells which have been latently infected with virus.
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Affiliation(s)
- Emma Poole
- Department of Medicine, University of Cambridge, box 157, Level 5 Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK;
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Human Cytomegalovirus Decreases Major Histocompatibility Complex Class II by Regulating Class II Transactivator Transcript Levels in a Myeloid Cell Line. J Virol 2020; 94:JVI.01901-19. [PMID: 31915281 DOI: 10.1128/jvi.01901-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/02/2020] [Indexed: 12/17/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous pathogen that encodes many proteins to modulate the host immune response. Extensive efforts have led to the elucidation of multiple strategies employed by HCMV to effectively block NK cell targeting of virus-infected cells and the major histocompatibility complex (MHC) class I-primed CD8+ T cell response. However, viral regulation of the MHC class II-mediated CD4+ T cell response is understudied in endogenous MHC class II-expressing cells, largely because the popular cell culture systems utilized for studying HCMV do not endogenously express MHC class II. Of the many cell types infected by HCMV in the host, myeloid cells, such as monocytes, are of particular importance due to their role in latency and subsequent dissemination throughout the host. We investigated the impact of HCMV infection on MHC class II in Kasumi-3 cells, a myeloid-progenitor cell line that endogenously expresses the MHC class II gene, HLA-DR. We observed a significant reduction in the expression of surface and total HLA-DR at 72 h postinfection (hpi) and 120 hpi in infected cells. The decrease in HLA-DR expression was independent of the expression of previously described viral genes that regulate the MHC class II complex or the unique short (US) region of HCMV, a region expressing many immunomodulatory genes. The altered surface level of HLA-DR was not a result of increased endocytosis and degradation but was a result of a reduction in HLA-DR transcripts due to a decrease in the expression of the class II transactivator (CIITA).IMPORTANCE Human cytomegalovirus (HCMV) is an opportunistic herpesvirus that is asymptomatic for healthy individuals but that can lead to severe pathology in patients with congenital infections and immunosuppressed patients. Thus, it is important to understand the modulation of the immune response by HCMV, which is understudied in the context of endogenous MHC class II regulation. Using Kasumi-3 cells as a myeloid progenitor cell model endogenously expressing MHC class II (HLA-DR), this study shows that HCMV decreases the expression of HLA-DR in infected cells by reducing the transcription of HLA-DR transcripts early during infection independently of the expression of previously implicated genes. This is an important finding, as it highlights a mechanism of immune evasion utilized by HCMV to decrease the expression of MHC class II in a relevant cell system that endogenously expresses the MHC class II complex.
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Lee JH, Pasquarella JR, Kalejta RF. Cell Line Models for Human Cytomegalovirus Latency Faithfully Mimic Viral Entry by Macropinocytosis and Endocytosis. J Virol 2019; 93:e01021-19. [PMID: 31391271 PMCID: PMC6803280 DOI: 10.1128/jvi.01021-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/05/2019] [Indexed: 02/06/2023] Open
Abstract
Human cytomegalovirus (HCMV) enters primary CD34+ hematopoietic progenitor cells by macropinocytosis, where it establishes latency in part because its tegument-transactivating protein, pp71, remains associated with endosomes and is therefore unable to initiate productive, lytic replication. Here we show that multiple HCMV strains also enter cell line models used to study latency by macropinocytosis and endocytosis. In all latency models tested, tegument-delivered pp71 was found to be colocalized with endosomal markers and was not associated with the seven other cytoplasmic localization markers tested. Like the capsid-associated pp150 tegument protein, we initially detected capsid proteins in association with endosomes but later detected them in the nucleus. Inhibitors of macropinocytosis and endocytosis reduced latent viral gene expression and precluded reactivation. Importantly, we utilized electron microscopy to observe entry by macropinocytosis and endocytosis, providing additional visual corroboration of the findings of our functional studies. Our demonstration that HCMV enters cell line models for latency in a manner indistinguishable from that of its entry into primary cells illustrates the utility of these cell lines for probing the mechanisms, host genetics, and small-molecule-mediated inhibition of HCMV entry into the cell types where it establishes latency.IMPORTANCE Primary cells cultured in vitro currently provide the highest available relevance for examining molecular and genetic requirements for the establishment, maintenance, and reactivation of HCMV latency. However, their expense, heterogeneity, and intransigence to both long-term culture and molecular or genetic modification create rigor and reproducibility challenges for HCMV latency studies. There are several cell line models for latency not obstructed by deficiencies inherent in primary cells. However, many researchers view cell line studies of latency to be physiologically irrelevant because of the perception that these models display numerous and significant differences from primary cells. Here, we show that the very first step in a latent HCMV infection, entry of the virus into cells, occurs in cell line models in a manner indistinguishable from that in which it occurs in primary CD34+ hematopoietic progenitor cells. Our data argue that experimental HCMV latency is much more similar than it is different in cell lines and primary cells.
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Affiliation(s)
- Jeong-Hee Lee
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Joseph R Pasquarella
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Robert F Kalejta
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Poole E, Huang CJZ, Forbester J, Shnayder M, Nachshon A, Kweider B, Basaj A, Smith D, Jackson SE, Liu B, Shih J, Kiskin FN, Roche K, Murphy E, Wills MR, Morrell NW, Dougan G, Stern-Ginossar N, Rana AA, Sinclair J. An iPSC-Derived Myeloid Lineage Model of Herpes Virus Latency and Reactivation. Front Microbiol 2019; 10:2233. [PMID: 31649625 PMCID: PMC6795026 DOI: 10.3389/fmicb.2019.02233] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 09/11/2019] [Indexed: 02/02/2023] Open
Abstract
Herpesviruses undergo life-long latent infection which can be life-threatening in the immunocompromised. Models of latency and reactivation of human cytomegalovirus (HCMV) include primary myeloid cells, cells known to be important for HCMV latent carriage and reactivation in vivo. However, primary cells are limited in availability, and difficult to culture and to genetically modify; all of which have hampered our ability to fully understand virus/host interactions of this persistent human pathogen. We have now used iPSCs to develop a model cell system to study HCMV latency and reactivation in different cell types after their differentiation down the myeloid lineage. Our results show that iPSCs can effectively mimic HCMV latency/reactivation in primary myeloid cells, allowing molecular interrogations of the viral latent/lytic switch. This model may also be suitable for analysis of other viruses, such as HIV and Zika, which also infect cells of the myeloid lineage.
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Affiliation(s)
- Emma Poole
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Jessica Forbester
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Miri Shnayder
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Aharon Nachshon
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Baraa Kweider
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Anna Basaj
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Daniel Smith
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Bin Liu
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Joy Shih
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Fedir N. Kiskin
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - K. Roche
- Cleveland Clinic, Lerner Research Institute, Cleveland, OH, United States
| | - E. Murphy
- Cleveland Clinic, Lerner Research Institute, Cleveland, OH, United States
| | - Mark R. Wills
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Gordon Dougan
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Noam Stern-Ginossar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Amer A. Rana
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - John Sinclair
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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Alcolea Palafox M, Franklin Benial AM, K Rastogi V. Biomolecules of 2-Thiouracil, 4-Thiouracil and 2,4-Dithiouracil: A DFT Study of the Hydration, Molecular Docking and Effect in DNA:RNAMicrohelixes. Int J Mol Sci 2019; 20:E3477. [PMID: 31311161 PMCID: PMC6678171 DOI: 10.3390/ijms20143477] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 12/17/2022] Open
Abstract
The molecular structure of 2-thiouracil, 4-thiouracil and 2,4-dithiouracil was analyzed under the effect of the first and second hydration shell by using the B3LYP density functional (DFT) method, and the results were compared to those obtained for the uracil molecule. A slight difference in the water distribution appears in these molecules. On the hydration of these molecules several trends in bond lengths and atomic charges were established. The ring in uracil molecule appears easier to be deformed and adapted to different environments as compared to that when it is thio-substituted. Molecular docking calculations of 2-thiouracil against three different pathogens: Bacillus subtilis, Escherichia coli and Candida albicans were carried out. Docking calculations of 2,4-dithiouracil ligand with various targeted proteins were also performed. Different DNA: RNA hybrid microhelixes with uridine, 2-thiouridine, 4-thiouridine and 2,4-dithiouridine nucleosides were optimized in a simple model with three nucleotide base pairs. Two main types of microhelixes were analyzed in detail depending on the intramolecular H-bond of the 2'-OH group. The weaker Watson-Crick (WC) base pair formed with thio-substituted uracil than with unsubstituted ones slightly deforms the helical and backbone parameters, especially with 2,4-dithiouridine. However, the thio-substitution significantly increases the dipole moment of the A-type microhelixes, as well as the rise and propeller twist parameters.
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Affiliation(s)
- M Alcolea Palafox
- Departamento de Química-Física, Facultad de CienciasQuímicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | | | - V K Rastogi
- Indian Spectroscopy Society, KC 68/1, Old Kavinagar, Ghaziabad 201002, India
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Human cytomegalovirus G protein-coupled receptor US28 promotes latency by attenuating c-fos. Proc Natl Acad Sci U S A 2019; 116:1755-1764. [PMID: 30647114 DOI: 10.1073/pnas.1816933116] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous pathogen that undergoes latency in cells of the hematopoietic compartment, although the mechanisms underlying establishment and maintenance of latency remain elusive. We previously reported that the HCMV-encoded G protein-coupled receptor (GPCR) homolog US28 is required for successful latent infection. We now show that US28 protein (pUS28) provided in trans complements the US28Δ lytic phenotype in myeloid cells, suggesting that sustained US28 expression is necessary for long-term latency. Furthermore, expression of pUS28 at the time of infection represses transcription from the major immediate early promoter (MIEP) within 24 h. However, this repression is only maintained in the presence of continual pUS28 expression provided in trans Our data also reveal that pUS28-mediated signaling attenuates both expression and phosphorylation of cellular fos (c-fos), an AP-1 transcription factor subunit, to repress MIEP-driven transcription. AP-1 binds to the MIEP and promotes lytic replication, and in line with this we find that US28Δ infection results in an increase in AP-1 binding to the MIEP, compared with WT latent infection. Pharmacological inhibition of c-fos represses the MIEP during US28Δ infection to levels similar to those we observe during WT latent infection. Together, our data reveal that US28 is required for both establishment and long-term maintenance of HCMV latency, which is modulated, at least in part, by repressing functional AP-1 binding to the MIEP.
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