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Chang PJ, Hung CH, Wang SS, Tsai PH, Shih YJ, Chen LY, Huang HY, Wei LH, Yen JB, Lin CL, Chen LW. Identification and characterization of two novel spliced genes located in the orf47-orf46-orf45 gene locus of Kaposi's sarcoma-associated herpesvirus. J Virol 2014; 88:10092-109. [PMID: 24965448 PMCID: PMC4136336 DOI: 10.1128/jvi.01445-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 06/16/2014] [Indexed: 12/29/2022] Open
Abstract
UNLABELLED The orf47-orf46-orf45 gene cluster of Kaposi's sarcoma-associated herpesvirus (KSHV) is known to serially encode glycoprotein L (gL), uracil DNA glycosylase, and a viral tegument protein. Here, we identify two novel mRNA variants, orf47/45-A and orf47/45-B, alternatively spliced from a tricistronic orf47-orf46-orf45 mRNA that is expressed in the orf47-orf46-orf45 gene locus during the early stages of viral reactivation. The spliced gene products, ORF47/45-A and ORF47/45-B, consist of only a partial region of gL (ORF47), a unique 7-amino-acid motif, and the complete tegument protein ORF45. Like the ORF45 protein, ORF47/45-A and ORF47/45-B expressed in cells sufficiently activate the phosphorylation of p90 ribosomal S6 kinase (RSK) and extracellular signal-regulated protein kinase (ERK). However, unlike ORF45, both ORF47/45-A and ORF47/45-B contain a signal peptide sequence and are localized at the endoplasmic reticulum (ER). Additionally, we found that ORF47/45-A and ORF47/45-B have an extra function that mediates the upregulation of GRP78, a master regulator of ER homeostasis. The important event regarding GRP78 upregulation can be observed in all tested KSHV-positive cell lines after viral reactivation, and knockdown of GRP78 in cells significantly impairs viral lytic cycle progression, especially at late lytic stages. Compared with some other viral glycoproteins synthesized through the ER, our results strongly implicate that the ORF47/45 proteins may serve as key effectors for controlling GRP78 expression and ER homeostasis in cells. Taken together, our findings provide evidence showing the reciprocal association between the modulation of ER homeostasis and the progression of the KSHV lytic cycle. IMPORTANCE Emerging evidence has shown that several viruses appear to use different strategies to control ER homeostasis for supporting their productive infections. The two parts of this study identify two aspects of the association between the regulation of ER homeostasis and the progression of the KSHV lytic cycle. The first part characterizes the function of two early lytic cycle proteins, ORF47/45-A and ORF47/45-B, on the activation of a major ER chaperone protein, GRP78. In addition to the ability to promote GRP78 upregulation, the ORF47/45 proteins also activate the phosphorylation of RSK and ERK. The second part reveals that upregulation of GRP78 is essential for the progression of the KSHV lytic cycle, especially at late stages. We therefore propose that activation of GRP78 expression by viral proteins at the early lytic stage may aid with the protection of host cells from severe ER stress and may directly involve the assembly or release of virions.
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MESH Headings
- DNA, Recombinant
- DNA, Viral/chemistry
- DNA, Viral/genetics
- Endoplasmic Reticulum Chaperone BiP
- Gene Expression Regulation, Viral
- Genes, Viral
- Herpesvirus 8, Human/genetics
- Herpesvirus 8, Human/physiology
- Humans
- Immediate-Early Proteins/genetics
- Molecular Sequence Data
- Multigene Family
- RNA, Messenger/genetics
- RNA, Viral/genetics
- Sequence Analysis, DNA
- Virus Replication
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Affiliation(s)
- Pey-Jium Chang
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang-Gung University, Taoyuan, Taiwan Department of Medical Research, Chang-Gung Memorial Hospital, Chiayi, Taiwan
| | - Chien-Hui Hung
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang-Gung University, Taoyuan, Taiwan
| | - Shie-Shan Wang
- Department of Pediatric Surgery, Chang-Gung Memorial Hospital, Chiayi, Taiwan
| | - Ping-Hsin Tsai
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang-Gung University, Taoyuan, Taiwan
| | - Ying-Ju Shih
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang-Gung University, Taoyuan, Taiwan
| | - Li-Yu Chen
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang-Gung University, Taoyuan, Taiwan
| | - Hsiao-Yun Huang
- Department of Pediatric Surgery, Chang-Gung Memorial Hospital, Chiayi, Taiwan
| | - Ling-Huei Wei
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang-Gung University, Taoyuan, Taiwan
| | - Ju-Bei Yen
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang-Gung University, Taoyuan, Taiwan Department of Pediatrics, Chang-Gung Memorial Hospital, Chiayi, Taiwan
| | - Chun-Liang Lin
- Department of Nephrology, Chang-Gung Memorial Hospital, Chiayi, Taiwan
| | - Lee-Wen Chen
- Department of Respiratory Care, Chang-Gung University of Science and Technology, Chiayi, Taiwan
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Wang F, Agnello G, Sotolongo N, Segatori L. Ca2+ homeostasis modulation enhances the amenability of L444P glucosylcerebrosidase to proteostasis regulation in patient-derived fibroblasts. ACS Chem Biol 2011; 6:158-68. [PMID: 21043486 DOI: 10.1021/cb100321m] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Gaucher's disease is caused by deficiency of lysosomal glucocerebrosidase (GC) activity and accumulation of GC substrate, glucosylceramide. A number of point mutations in GC encoding gene have been reported to destabilize the enzyme native structure, resulting in protein misfolding and degradation. Particularly, the L444P GC variant, often associated with neuropathic manifestations of the disease, is severely destabilized and immediately degraded, resulting in complete loss of enzymatic activity. In addition, glucosylceramide accumulation causes Ca(2+) efflux from the endoplasmic reticulum (ER) through ryanodine receptors (RyRs) in the neurons of Gaucher's disease patients. We hypothesized that excessive [Ca(2+)](ER) efflux impairs ER folding and studied how modulation of [Ca(2+)](ER) affects folding of L444P GC in patient-derived fibroblasts. We report that RyRs blockers mediated [Ca(2+)] modulation, recreating a "wild type-like" folding environment in the ER, more amenable to rescuing the folding of mutated L444P GC through proteostasis regulation. Treating patient-derived fibroblasts with a RyRs blocker and a proteostasis modulator, MG-132, results in enhanced folding, trafficking, and activity of the severely destabilized L444P GC variant. Global gene expression profiling and mechanistic studies were conducted to investigate the folding quality control expression pattern conducive to native folding of mutated L444P GC and revealed that the ER-lumenal BiP/GRP78 plays a key role in the biogenesis of this GC variant.
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Affiliation(s)
- Fan Wang
- Department of Chemical and Biomolecular Engineering and ‡Department of Biochemistry and Cell Biology, Rice University, CHBE-MS 362, 6100 Main St., Houston, Texas 77005, United States
| | - Giulia Agnello
- Department of Chemical and Biomolecular Engineering and ‡Department of Biochemistry and Cell Biology, Rice University, CHBE-MS 362, 6100 Main St., Houston, Texas 77005, United States
| | - Natasha Sotolongo
- Department of Chemical and Biomolecular Engineering and ‡Department of Biochemistry and Cell Biology, Rice University, CHBE-MS 362, 6100 Main St., Houston, Texas 77005, United States
| | - Laura Segatori
- Department of Chemical and Biomolecular Engineering and ‡Department of Biochemistry and Cell Biology, Rice University, CHBE-MS 362, 6100 Main St., Houston, Texas 77005, United States
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Koziol C, Kobayashi N, Müller IM, Müller WEG. Cloning of sponge heat shock proteins: evolutionary relationships between the major kingdoms. J ZOOL SYST EVOL RES 2009. [DOI: 10.1111/j.1439-0469.1998.tb00782.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Renna M, Caporaso MG, Bonatti S, Kaufman RJ, Remondelli P. Regulation of ERGIC-53 gene transcription in response to endoplasmic reticulum stress. J Biol Chem 2007; 282:22499-512. [PMID: 17535801 DOI: 10.1074/jbc.m703778200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Accumulation of unfolded proteins within the endoplasmic reticulum (ER) activates the unfolded protein response, also known as the ER stress response. We previously demonstrated that ER stress induces transcription of the ER Golgi intermediate compartment protein ERGIC-53. To investigate the molecular events that regulate unfolded protein response-mediated induction of the gene, we have analyzed the transcriptional regulation of ERGIC-53. We found that the ERGIC-53 promoter contains a single cis-acting element that mediates induction of the gene by thapsigargin and other ER stress-causing agents. This ER stress response element proved to retain a novel structure and to be highly conserved in mammalian ERGIC-53 genes. The ER stress response element identified contains a 5'-end CCAAT sequence that constitutively binds NFY/CBF and, 9 nucleotides away, a 3'-end region (5'-CCCTGTTGGCCATC-3') that is equally important for ER stress-mediated induction of the gene. This sequence is the binding site for endogenous YY1 at the 5'-CCCTGTTGG-3' part and for undefined factors at the CCATC 3'-end. ATF6 alpha-YY1, but not XBP1, interacted with the ERGIC-53 regulatory region and activated ERGIC-53 ER stress response element-dependent transcription. A molecular model for the transcriptional regulation of the ERGIC-53 gene is proposed.
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Affiliation(s)
- Maurizio Renna
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Salerno, Fisciano-Salerno I-84034, Italy
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Ramsay RG, Ciznadija D, Mantamadiotis T, Anderson R, Pearson R. Expression of stress response protein glucose regulated protein-78 mediated by c-Myb. Int J Biochem Cell Biol 2005; 37:1254-68. [PMID: 15778089 DOI: 10.1016/j.biocel.2004.12.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Revised: 12/10/2004] [Accepted: 12/23/2004] [Indexed: 10/25/2022]
Abstract
Glucose regulated protein-78, GRP78 has been implicated in the protection of tumor cells from cytotoxic damage and apoptosis. When protein profiles of colon cell lines were investigated we found remarkably high GRP78 expression in two cell lines. These cell lines express elevated levels of the transcription factor c-Myb due to genomic amplification of the c-myb locus and we hypothesized that c-Myb regulates GRP78 expression in colon cancer cells. The promoters of human and murine GRP78 and the related family member GRP94 were examined and potential c-Myb binding sites were identified and characterized. DNA binding studies with recombinant c-Myb and nuclear extracts together with ChIP assays on colon cell lines validated these sites. Endogenous GRP78 expression was further induced in these colon cells in response to Thapsigargin treatment, a potent inducer of the unfolded protein response. Transactivation studies with the human GRP78 promoter in colon cell lines showed reporter activity was dependent upon the presence of a conserved c-Myb binding site independent of sequences associated with the unfolded protein response. Finally, over-expression of c-Myb induced the endogenous GRP78 gene. These data suggest that amplification of c-myb in tumor cells may lead to robust GRP78 gene induction, which may in turn assist cells in survival under conditions of oxygen deprivation and nutrient stress.
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Affiliation(s)
- Robert G Ramsay
- Differentiation and Transcription Laboratory, Trescowthick Research Laboratories, Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne 3002, Australia.
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Portig I, Pankuweit S, Lottspeich F, Maisch B. Identification of stress proteins in endothelial cells. Electrophoresis 1996; 17:803-8. [PMID: 8738348 DOI: 10.1002/elps.1150170431] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Endothelial cells have been shown to play a major role in the pathophysiology of various diseases including ischemic heart disease and viral infection leading to myocarditis or dilated cardiomyopathy, conditions in which stress proteins (heat shock protein-hsp; glucose-related protein - grp) are likely to be involved. For further characterization of stress proteins and their possible role in these diseases, the major stress proteins in human endothelial cells were separated by two-dimensional polyacrylamide gel electrophoresis with immobilized pH gradients in the first dimension and identified by immunoblotting and either N-terminal or internal amino acid sequencing, respectively. Ubiquitin, hsp27, hsp60, hsp70, heat shock cognate protein 70, grp78 and grp75 were found to be constitutively expressed; hsp72 was found in stressed cells, exclusively, in line with results obtained in other human cell lines. Three additional proteins with molecular masses between 34 and 40 were regularly detected in stressed cells that were found to have identical amino acid sequences with those of members of the hsp70 family.
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Affiliation(s)
- I Portig
- Klinikum der Philipps-Universität, SP Kardiologie, Marburg, Germany
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Nguyen TO, Capra JD, Sontheimer RD. Calreticulin is transcriptionally upregulated by heat shock, calcium and heavy metals. Mol Immunol 1996; 33:379-86. [PMID: 8676889 DOI: 10.1016/0161-5890(95)00149-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Calreticulin is a new human rheumatic disease-associated autoantigen that plays a multifaceted role in cell biology. In earlier studies, this protein was shown to share an intimate relationship with the Ro/SS-A autoantigen complex, although the nature of this association continues to be debated. Since modulation of the Ro/SS-A autoantigen in epidermal keratinocytes has been implicated in the pathogenesis of subacute cutaneous lupus erythematosus and neonatal lupus erythematosus, we have begun to examine the transcriptional regulation of calreticulin. A 504 bp calreticulin promoter fragment was subcloned into a reporter gene plasmid containing firefly luciferase. Calcium ionophore, heat shock, and heavy metals such as zinc and cadmium were consistently found to increase calreticulin transcriptional activities in A431 cells (a human epidermoid squamous carcinoma cell line) under transient transfection conditions. These studies suggest that (a) calreticulin is regulated at the transcriptional level, and (b) calreticulin, like some other LE-related autoantigens, appears to function as a heat shock/stress-response gene.
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Affiliation(s)
- T O Nguyen
- Department of Dermatology, University of Texas Southwestern Medical Center, Dallas 75235, USA
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Koumenis C, Nunez-Regueiro M, Raju U, Cook R, Eskin A. Identification of three proteins in the eye of Aplysia, whose synthesis is altered by serotonin (5-HT). Possible involvement of these proteins in the ocular circadian system. J Biol Chem 1995; 270:14619-27. [PMID: 7782325 DOI: 10.1074/jbc.270.24.14619] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Previous results using translation inhibitors in the ocular circadian system of Aplysia suggest that protein synthesis may be involved in the light and serotonin (5-HT) entrainment pathways or perhaps in the circadian oscillator. Proteins have been previously identified whose synthesis was altered by treatments of light capable of perturbing the phase of the circadian rhythm in the eye of Aplysia. We extended these studies by investigating the effects of other treatments that perturb the ocular circadian rhythm on protein synthesis. 5-HT altered the synthesis of nine proteins. Interestingly, five of the proteins affected by treatments with 5-HT were previously shown to be affected by treatments with light. Four of the proteins affected by treatments with 5-HT were also affected by treatments with analogs of cAMP, a treatment which mimics the effects of 5-HT on the ocular circadian rhythm. To identify the cellular function of some of these proteins, we obtained their partial amino acid sequences. Based on these sequences and additional characterizations, a 78-kDa, pI 5.6 Aplysia protein appears to be glucose-regulated protein 78/binding protein, and a 36-kDa, pI 5.7 Aplysia protein appears to be porin/voltage-dependent anion channel. Heat shock experiments on Aplysia eyes revealed that yet another one of the Aplysia proteins (70 kDa) affected by 5-HT appears to be a heat-inducible member (heat shock protein 70) of the family of heat shock proteins. These findings suggest that these three identified proteins, together or individually, may be involved in some way in the regulation of the timing of the circadian oscillator in the eye of Aplysia.
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Affiliation(s)
- C Koumenis
- Department of Biochemical and Biophysical Sciences, University of Houston, Texas 77204, USA
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