1
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Feng SW, Wu ZS, Chiu YL, Huang SM. Exploring the Functional Roles of Telomere Maintenance 2 in the Tumorigenesis of Glioblastoma Multiforme and Drug Responsiveness to Temozolomide. Int J Mol Sci 2023; 24:ijms24119256. [PMID: 37298208 DOI: 10.3390/ijms24119256] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/13/2023] [Accepted: 05/23/2023] [Indexed: 06/12/2023] Open
Abstract
Glioblastoma multiforme (GBM) is a grade IV human glioma. It is the most malignant primary central nervous system tumor in adults, accounting for around 15% of intracranial neoplasms and 40-50% of all primary malignant brain tumors. However, the median survival time of GBM patients is still less than 15 months, even after treatment with surgical resection, concurrent chemoradiotherapy, and adjuvant chemotherapy with temozolomide (TMZ). Telomere maintenance 2 (TELO2) mRNA is highly expressed in high-grade glioma patients, and its expression correlates with shorter survival outcomes. Hence, it is urgent to address the functional role of TELO2 in the tumorigenesis and TMZ treatment of GBM. In this study, we knocked down TELO2 mRNA in GBM8401 cells, a grade IV GBM, compared with TELO2 mRNA overexpression in human embryonic glial SVG p12 cells and normal human astrocyte (NHA) cells. We first analyzed the effect of TELO2 on the Elsevier pathway and Hallmark gene sets in GBM8401, SVG p12, and NHA via an mRNA array analysis. Later, we further examined and analyzed the relationship between TELO2 and fibroblast growth factor receptor 3, cell cycle progression, epithelial-mesenchymal transient (EMT), reactive oxygen species (ROS), apoptosis, and telomerase activity. Our data showed that TELO2 is involved in several functions of GBM cells, including cell cycle progression, EMT, ROS, apoptosis, and telomerase activity. Finally, we examined the crosstalk between TELO2 and the responsiveness of TMZ or curcumin mediated through the TELO2-TTI1-TTI2 complex, the p53-dependent complex, the mitochondrial-related complex, and signaling pathways in GBM8401 cells. In summary, our work provides new insight that TELO2 might modulate target proteins mediated through the complex of phosphatidylinositol 3-kinase-related kinases in its involvement in cell cycle progression, EMT, and drug response in GBM patients.
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Affiliation(s)
- Shao-Wei Feng
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei 114, Taiwan
- Department of Neurological Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
| | - Zih-Syuan Wu
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan
| | - Yi-Lin Chiu
- Department of Biochemistry, National Defense Medical Center, Taipei 114, Taiwan
| | - Shih-Ming Huang
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei 114, Taiwan
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan
- Department of Biochemistry, National Defense Medical Center, Taipei 114, Taiwan
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2
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The Role of Hsp90-R2TP in Macromolecular Complex Assembly and Stabilization. Biomolecules 2022; 12:biom12081045. [PMID: 36008939 PMCID: PMC9406135 DOI: 10.3390/biom12081045] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/19/2022] [Accepted: 07/25/2022] [Indexed: 01/27/2023] Open
Abstract
Hsp90 is a ubiquitous molecular chaperone involved in many cell signaling pathways, and its interactions with specific chaperones and cochaperones determines which client proteins to fold. Hsp90 has been shown to be involved in the promotion and maintenance of proper protein complex assembly either alone or in association with other chaperones such as the R2TP chaperone complex. Hsp90-R2TP acts through several mechanisms, such as by controlling the transcription of protein complex subunits, stabilizing protein subcomplexes before their incorporation into the entire complex, and by recruiting adaptors that facilitate complex assembly. Despite its many roles in protein complex assembly, detailed mechanisms of how Hsp90-R2TP assembles protein complexes have yet to be determined, with most findings restricted to proteomic analyses and in vitro interactions. This review will discuss our current understanding of the function of Hsp90-R2TP in the assembly, stabilization, and activity of the following seven classes of protein complexes: L7Ae snoRNPs, spliceosome snRNPs, RNA polymerases, PIKKs, MRN, TSC, and axonemal dynein arms.
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3
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Tel2 regulates redifferentiation of bipotential progenitor cells via Hhex during zebrafish liver regeneration. Cell Rep 2022; 39:110596. [PMID: 35385752 DOI: 10.1016/j.celrep.2022.110596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/27/2022] [Accepted: 03/09/2022] [Indexed: 02/07/2023] Open
Abstract
Upon extensive hepatocyte loss or impaired hepatocyte proliferation, liver regeneration occurs via biliary epithelial cell (BEC) transdifferentiation, which includes dedifferentiation of BECs into bipotential progenitor cells (BP-PCs) and then redifferentiation of BP-PCs to nascent hepatocytes and BECs. This BEC-driven liver regeneration involves reactivation of hepatoblast markers, but the underpinning mechanisms and their effects on liver regeneration remain largely unknown. Using a zebrafish extensive hepatocyte ablation model, we perform an N-ethyl-N-nitrosourea (ENU) forward genetic screen and identify a liver regeneration mutant, liver logan (lvl), in which the telomere maintenance 2 (tel2) gene is mutated. During liver regeneration, the tel2 mutation specifically inhibits transcriptional activation of a hepatoblast marker, hematopoietically expressed homeobox (hhex), in BEC-derived cells, which blocks BP-PC redifferentiation. Mechanistic studies show that Tel2 associates with the hhex promoter region and promotes hhex transcription. Our results reveal roles of Tel2 in the BP-PC redifferentiation process of liver regeneration by activating hhex.
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4
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Palma M, Leroy C, Salomé-Desnoulez S, Werkmeister E, Kong R, Mongy M, Le Hir H, Lejeune F. A role for AKT1 in nonsense-mediated mRNA decay. Nucleic Acids Res 2021; 49:11022-11037. [PMID: 34634811 PMCID: PMC8565340 DOI: 10.1093/nar/gkab882] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 09/15/2021] [Accepted: 09/17/2021] [Indexed: 12/16/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a highly regulated quality control mechanism through which mRNAs harboring a premature termination codon are degraded. It is also a regulatory pathway for some genes. This mechanism is subject to various levels of regulation, including phosphorylation. To date only one kinase, SMG1, has been described to participate in NMD, by targeting the central NMD factor UPF1. Here, screening of a kinase inhibitor library revealed as putative NMD inhibitors several molecules targeting the protein kinase AKT1. We present evidence demonstrating that AKT1, a central player in the PI3K/AKT/mTOR signaling pathway, plays an essential role in NMD, being recruited by the UPF3X protein to phosphorylate UPF1. As AKT1 is often overactivated in cancer cells and as this should result in increased NMD efficiency, the possibility that this increase might affect cancer processes and be targeted in cancer therapy is discussed.
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Affiliation(s)
- Martine Palma
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France.,Unité tumorigenèse et résistance aux traitements, Institut Pasteur de Lille, F-59000 Lille, France
| | - Catherine Leroy
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France.,Unité tumorigenèse et résistance aux traitements, Institut Pasteur de Lille, F-59000 Lille, France
| | - Sophie Salomé-Desnoulez
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UMS 2014 - PLBS, F-59000 Lille, France
| | - Elisabeth Werkmeister
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UMS 2014 - PLBS, F-59000 Lille, France.,Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR9017 - CIIL - center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Rebekah Kong
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France.,Unité tumorigenèse et résistance aux traitements, Institut Pasteur de Lille, F-59000 Lille, France
| | - Marc Mongy
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UMS 2014 - PLBS, F-59000 Lille, France
| | - Hervé Le Hir
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, 46 rue d'Ulm, 75005 Paris, France
| | - Fabrice Lejeune
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France.,Unité tumorigenèse et résistance aux traitements, Institut Pasteur de Lille, F-59000 Lille, France
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5
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Guo Y, Tocchini C, Ciosk R. CLK-2/TEL2 is a conserved component of the nonsense-mediated mRNA decay pathway. PLoS One 2021; 16:e0244505. [PMID: 33444416 PMCID: PMC7808604 DOI: 10.1371/journal.pone.0244505] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/10/2020] [Indexed: 11/19/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) controls eukaryotic mRNA quality, inducing the degradation of faulty transcripts. Key players in the NMD pathway were originally identified, through genetics, in Caenorhabditis elegans as smg (suppressor with morphological effect on genitalia) genes. Using forward genetics and fluorescence-based NMD reporters, we reexamined the genetic landscape underlying NMD. Employing a novel strategy for mapping sterile mutations, Het-Map, we identified clk-2, a conserved gene previously implicated in DNA damage signaling, as a player in the nematode NMD. We find that CLK-2 is expressed predominantly in the germline, highlighting the importance of auxiliary factors in tissue-specific mRNA decay. Importantly, the human counterpart of CLK-2/TEL2, TELO2, has been also implicated in the NMD, suggesting a conserved role of CLK-2/TEL2 proteins in mRNA surveillance. Recently, variants of TELO2 have been linked to an intellectual disability disorder, the You-Hoover-Fong syndrome, which could be related to its function in the NMD.
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Affiliation(s)
- Yanwu Guo
- Department of Biosciences, University of Oslo, Oslo, Norway
| | | | - Rafal Ciosk
- Department of Biosciences, University of Oslo, Oslo, Norway
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
- * E-mail:
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6
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Zhang C, Mi J, Deng Y, Deng Z, Long D, Liu Z. DNMT1 Enhances the Radiosensitivity of HPV-Positive Head and Neck Squamous Cell Carcinomas via Downregulating SMG1. Onco Targets Ther 2020; 13:4201-4211. [PMID: 32523356 PMCID: PMC7237113 DOI: 10.2147/ott.s227395] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 02/18/2020] [Indexed: 01/21/2023] Open
Abstract
Introduction Head and neck squamous cell carcinoma (HNSCC), which rank the 7th malignant tumors worldwide, is closely related to methylation and HPV infection. Ionizing radiation therapy is the main strategy for HNSCC patients in advanced stage. Previously, HPV-positive HNSCC predict better prognosis than HPV-negative HNSCCs under radiotherapy, however its molecular mechanism is unresolved. SMG1 serves as a potential tumor suppressor in various cancers, including HNSCC. Methods The mRNAs and proteins expression of HPV E6/E7, p16, p53, DNMT1, SMG1 were detected after different treatments by qPCR and Western blot. The clone formation ability was measured in radiation dose after different treatments. Results In our study, the expression of HPV16 E6, DNA Methyltransferase 1(DNMT1) and SMG1 in head and neck carcinomas cell lines was detected by RT-qPCR and Western blot. Forced E6 level in HPV-negative cells by overexpression plasmid promoted the expression of DNMT1, which resulted in decreased SMG1 expression. Silenced SMG1 in HPV-negative HNSCC cells elicited increased radiation sensitivity, suggesting that SMG1 may be an effective switch to regulate the effect of radiotherapy in HNSCC. Conclusion Our study indicated that DNMT1 enhances the radiosensitivity of HPV-positive head and neck squamous cell carcinomas via downregulating SMG1.
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Affiliation(s)
- Chunlin Zhang
- Department of Otorhinolaryngology, Head and Neck Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People's Republic of China
| | - Jiaoping Mi
- Department of Otorhinolaryngology, Head and Neck Surgery, The Fifth Affiliated Hospital of Sun Yat-Sun University, Zunyi, People's Republic of China
| | - Yuan Deng
- Department of Otorhinolaryngology, Head and Neck Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People's Republic of China
| | - Zeyi Deng
- Department of Otorhinolaryngology, Head and Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, People's Republic of China
| | - Dan Long
- Department of Otorhinolaryngology, Head and Neck Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People's Republic of China.,The Graduate School of Zunyi Medical University, Zunyi, People's Republic of China
| | - Zhaohui Liu
- Department of Otorhinolaryngology, Head and Neck Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People's Republic of China
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7
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Park J, Seo JW, Ahn N, Park S, Hwang J, Nam JW. UPF1/SMG7-dependent microRNA-mediated gene regulation. Nat Commun 2019; 10:4181. [PMID: 31519907 PMCID: PMC6744440 DOI: 10.1038/s41467-019-12123-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 08/20/2019] [Indexed: 12/16/2022] Open
Abstract
The stability and quality of metazoan mRNAs are under microRNA (miRNA)-mediated and nonsense-mediated control. Although UPF1, a core mediator of nonsense-mediated mRNA decay (NMD), mediates the decay of target mRNA in a 3′UTR-length-dependent manner, the detailed mechanism remains unclear. Here, we suggest that 3′UTR-length-dependent mRNA decay is not mediated by nonsense mRNAs but rather by miRNAs that downregulate target mRNAs via Ago-associated UPF1/SMG7. Global analyses of mRNAs in response to UPF1 RNA interference in miRNA-deficient cells reveal that 3′UTR-length-dependent mRNA decay by UPF1 requires canonical miRNA targeting. The destabilization of miRNA targets is accomplished by the combination of Ago2 and UPF1/SMG7, which may recruit the CCR4-NOT deadenylase complex. Indeed, loss of the SMG7-deadenylase complex interaction increases the levels of transcripts regulated by UPF1-SMG7. This UPF1/SMG7-dependent miRNA-mediated mRNA decay pathway may enable miRNA targeting to become more predictable and expand the miRNA-mRNA regulatory network. UPF1 mediates the decay of target mRNA in a 3′ untranslated region (UTR)-length-dependent manner. Here the authors reveal that the 3′UTR-length-dependent regulation of UPF1-dependent mRNA decay occurs through EJC-independent but miRNA-dependent regulation.
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Affiliation(s)
- Jungyun Park
- Graduate School for Biomedical Science & Engineering, Hanyang University, Seoul, Republic of Korea
| | - Jwa-Won Seo
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea
| | - Narae Ahn
- Graduate School for Biomedical Science & Engineering, Hanyang University, Seoul, Republic of Korea
| | - Seokju Park
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea
| | - Jungwook Hwang
- Graduate School for Biomedical Science & Engineering, Hanyang University, Seoul, Republic of Korea. .,Department of Medical Genetics, College of Medicine, Hanyang University, Seoul, Republic of Korea.
| | - Jin-Wu Nam
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea. .,Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul, Republic of Korea.
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8
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Hong D, Park T, Jeong S. Nuclear UPF1 Is Associated with Chromatin for Transcription-Coupled RNA Surveillance. Mol Cells 2019; 42:523-529. [PMID: 31234619 PMCID: PMC6681869 DOI: 10.14348/molcells.2019.0116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 06/19/2019] [Accepted: 06/19/2019] [Indexed: 01/26/2023] Open
Abstract
mRNA quality is controlled by multiple RNA surveillance machineries to reduce errors during gene expression processes in eukaryotic cells. Nonsense-mediated mRNA decay (NMD) is a well-characterized mechanism that degrades error-containing transcripts during translation. The ATP-dependent RNA helicase up-frameshift 1 (UPF1) is a key player in NMD that is mostly prevalent in the cytoplasm. However, recent studies on UPF1-RNA interaction suggest more comprehensive roles of UPF1 on diverse forms of target transcripts. Here we used subcellular fractionation and immunofluorescence to understand such complex functions of UPF1. We demonstrated that UPF1 can be localized to the nucleus and predominantly associated with the chromatin. Moreover, we showed that UPF1 associates more strongly with the chromatin when the transcription elongation and translation inhibitors were used. These findings suggest a novel role of UPF1 in transcription elongation-coupled RNA machinery in the chromatin, as well as in translation-coupled NMD in the cytoplasm. Thus, we propose that cytoplasmic UPF1-centric RNA surveillance mechanism could be extended further up to the chromatin-associated UPF1 and cotranscriptional RNA surveillance. Our findings could provide the mechanistic insights on extensive regulatory roles of UPF1 for many cellular RNAs.
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Affiliation(s)
- Dawon Hong
- Graduate Department of Bioconvergence Science and Technology, Dankook University, Yongin 16892,
Korea
| | - Taeyoung Park
- Graduate Department of Bioconvergence Science and Technology, Dankook University, Yongin 16892,
Korea
| | - Sunjoo Jeong
- Graduate Department of Bioconvergence Science and Technology, Dankook University, Yongin 16892,
Korea
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9
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Oh Y, Park J, Kim JI, Chang MY, Lee SH, Cho YH, Hwang J. Lin28B and miR-142-3p regulate neuronal differentiation by modulating Staufen1 expression. Cell Death Differ 2017; 25:432-443. [PMID: 29099484 DOI: 10.1038/cdd.2017.182] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 08/15/2017] [Accepted: 09/19/2017] [Indexed: 02/06/2023] Open
Abstract
Staufen1 (STAU1) and Lin28B are RNA-binding proteins that are involved in neuronal differentiation as a function of post-transcriptional regulation. STAU1 triggers post-transcriptional regulation, including mRNA export, mRNA relocation, translation and mRNA decay. Lin28B also has multiple functions in miRNA biogenesis and the regulation of translation. Here, we examined the connection between STAU1 and Lin28B and found that Lin28B regulates the abundance of STAU1 mRNA via miRNA maturation. Decreases in the expression of both STAU1 and Lin28B were observed during neuronal differentiation. Depletion of STAU1 or Lin28B inhibited neuronal differentiation, and overexpression of STAU1 or Lin28B enhanced neuronal differentiation. Interestingly, the stability of STAU1 mRNA was modulated by miR-142-3p, whose maturation was regulated by Lin28B. Thus, miR-142-3p expression increased as Lin28B expression decreased during differentiation, leading to the reduction of STAU1 expression. The transcriptome from Staufen-mediated mRNA decay (SMD) targets during differentiation was analyzed, confirming that STAU1 was a key factor in neuronal differentiation. In support of this finding, regulation of STAU1 expression in mouse neural precursor cells had the same effects on neuronal differentiation as it did in human neuroblastoma cells. These results revealed the collaboration of two RNA-binding proteins, STAU1 and Lin28B, as a regulatory mechanism in neuronal differentiation.
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Affiliation(s)
- Younseo Oh
- Graduate School for Biomedical Science & Engineering, Seoul, Korea
| | - Jungyun Park
- Graduate School for Biomedical Science & Engineering, Seoul, Korea
| | - Jin-Il Kim
- Graduate School for Biomedical Science & Engineering, Seoul, Korea
| | | | - Sang-Hun Lee
- Department of Biochemistry and Molecular Biology, College of Medicine, Seoul, Korea
| | - Youl-Hee Cho
- Department of Medical Genetics, College of Medicine, Hanyang University, Seoul, Korea
| | - Jungwook Hwang
- Graduate School for Biomedical Science & Engineering, Seoul, Korea.,Department of Medical Genetics, College of Medicine, Hanyang University, Seoul, Korea
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10
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Mammalian ECD Protein Is a Novel Negative Regulator of the PERK Arm of the Unfolded Protein Response. Mol Cell Biol 2017; 37:MCB.00030-17. [PMID: 28652267 PMCID: PMC5574048 DOI: 10.1128/mcb.00030-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 06/17/2017] [Indexed: 01/01/2023] Open
Abstract
Mammalian Ecdysoneless (ECD) is a highly conserved ortholog of the DrosophilaEcd gene product whose mutations impair the synthesis of Ecdysone and produce cell-autonomous survival defects, but the mechanisms by which ECD functions are largely unknown. Here we present evidence that ECD regulates the endoplasmic reticulum (ER) stress response. ER stress induction led to a reduced ECD protein level, but this effect was not seen in PKR-like ER kinase knockout (PERK-KO) or phosphodeficient eukaryotic translation initiation factor 2α (eIF2α) mouse embryonic fibroblasts (MEFs); moreover, ECD mRNA levels were increased, suggesting impaired ECD translation as the mechanism for reduced protein levels. ECD colocalizes and coimmunoprecipitates with PERK and GRP78. ECD depletion increased the levels of both phospho-PERK (p-PERK) and p-eIF2α, and these effects were enhanced upon ER stress induction. Reciprocally, overexpression of ECD led to marked decreases in p-PERK, p-eIF2α, and ATF4 levels but robust increases in GRP78 protein levels. However, GRP78 mRNA levels were unchanged, suggesting a posttranscriptional event. Knockdown of GRP78 reversed the attenuating effect of ECD overexpression on PERK signaling. Significantly, overexpression of ECD provided a survival advantage to cells upon ER stress induction. Taken together, our data demonstrate that ECD promotes survival upon ER stress by increasing GRP78 protein levels to enhance the adaptive folding protein in the ER to attenuate PERK signaling.
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11
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Inoue H, Sugimoto S, Takeshita Y, Takeuchi M, Hatanaka M, Nagao K, Hayashi T, Kokubu A, Yanagida M, Kanoh J. CK2 phospho-independent assembly of the Tel2-associated stress-signaling complexes in Schizosaccharomyces pombe. Genes Cells 2016; 22:59-70. [PMID: 27935167 DOI: 10.1111/gtc.12454] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 10/30/2016] [Indexed: 02/03/2023]
Abstract
An evolutionarily conserved protein Tel2 regulates a variety of stress signals. In mammals, TEL2 associates with TTI1 and TTI2 to form the Triple T (TTT: TEL2-TTI1-TTI2) complex as well as with all the phosphatidylinositol 3-kinase-like kinases (PIKKs) and the R2TP (Ruvbl1-Ruvbl2-Tah1-Pih1 in budding yeast)/prefoldin-like complex that associates with HSP90. The phosphorylation of TEL2 by casein kinase 2 (CK2) enables direct binding of PIHD1 (mammalian Pih1) to TEL2 and is important for the stability and the functions of PIKKs. However, the regulatory mechanisms of Tel2 in fission yeast Schizosaccharomyces pombe remain largely unknown. Here, we report that S. pombe Tel2 is phosphorylated by CK2 at Ser490 and Thr493. Tel2 forms the TTT complex with Tti1 and Tti2 and also associates with PIKKs, Rvb2, and Hsp90 in vivo; however, the phosphorylation of Tel2 affects neither the stability of the Tel2-associated proteins nor their association with Tel2. Thus, Tel2 stably associates with its binding partners irrespective of its phosphorylation. Furthermore, the Tel2 phosphorylation by CK2 is not required for the various stress responses to which PIKKs are pivotal. Our results suggest that the Tel2-containing protein complexes are conserved among eukaryotes, but the molecular regulation of their formation has been altered during evolution.
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Affiliation(s)
- Haruna Inoue
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shizuka Sugimoto
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yumiko Takeshita
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Miho Takeuchi
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Mitsuko Hatanaka
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 909-0495, Japan
| | - Koji Nagao
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 909-0495, Japan
| | - Takeshi Hayashi
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 909-0495, Japan
| | - Aya Kokubu
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 909-0495, Japan
| | - Mitsuhiro Yanagida
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 909-0495, Japan
| | - Junko Kanoh
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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12
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Park J, Ahn S, Jayabalan AK, Ohn T, Koh HC, Hwang J. Insulin Signaling Augments eIF4E-Dependent Nonsense-Mediated mRNA Decay in Mammalian Cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1859:896-905. [PMID: 26708722 DOI: 10.1016/j.bbagrm.2015.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 12/14/2015] [Accepted: 12/17/2015] [Indexed: 12/13/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) modulates the level of mRNA harboring a premature termination codon (PTC) in a translation-dependent manner. Inhibition of translation is known to impair NMD; however, few studies have investigated the correlation between enhanced translation and increased NMD. Here, we demonstrate that insulin signaling events increase translation, leading to an increase in NMD of eIF4E-bound transcripts. We provide evidence that (i) insulin-mediated enhancement of translation augments NMD and rapamycin abrogates this enhancement; (ii) an increase in AKT phosphorylation due to inhibition of PTEN facilitates NMD; (iii) insulin stimulation increases the binding of up-frameshift factor 1 (UPF1), most likely to eIF4E-bound PTC-containing transcripts; and (iv) insulin stimulation induces the colocalization of UPF1 and eIF4E in processing bodies. These results illustrate how extracellular signaling promotes the removal of eIF4E-bound NMD targets.
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Affiliation(s)
- Jungyun Park
- Graduate School for Biomedical Science & Engineering, FTC1202-8, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Seyoung Ahn
- Graduate School for Biomedical Science & Engineering, FTC1202-8, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Aravinth K Jayabalan
- Department of Cellular and Molecular Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea
| | - Takbum Ohn
- Department of Cellular and Molecular Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea
| | - Hyun Chul Koh
- Department of Pharmacology, College of Medicine, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
| | - Jungwook Hwang
- Graduate School for Biomedical Science & Engineering, FTC1202-8, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea; Department of Medical Genetics, College of Medicine, FTC1202-8, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
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13
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Kim MY, Park J, Lee JJ, Ha DH, Kim J, Kim CG, Hwang J, Kim CG. Staufen1-mediated mRNA decay induces Requiem mRNA decay through binding of Staufen1 to the Requiem 3'UTR. Nucleic Acids Res 2014; 42:6999-7011. [PMID: 24799437 PMCID: PMC4066795 DOI: 10.1093/nar/gku388] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Requiem (REQ/DPF2) was originally identified as an apoptosis-inducing protein in mouse myeloid cells and belongs to the novel Krüppel-type zinc finger d4-protein family of proteins, which includes neuro-d4 (DPF1) and cer-d4 (DPF3). Interestingly, when a portion of the REQ messenger ribonucleic acid (mRNA) 3′ untranslated region (3′UTR), referred to as G8, was overexpressed in K562 cells, β-globin expression was induced, suggesting that the 3′UTR of REQ mRNA plays a physiological role. Here, we present evidence that the REQ mRNA 3′UTR, along with its trans-acting factor, Staufen1 (STAU1), is able to reduce the level of REQ mRNA via STAU1-mediated mRNA decay (SMD). By screening a complementary deoxyribonucleic acid (cDNA) expression library with an RNA–ligand binding assay, we identified STAU1 as an interactor of the REQ mRNA 3′UTR. Specifically, we provide evidence that STAU1 binds to putative 30-nucleotide stem–loop-structured RNA sequences within the G8 region, which we term the protein binding site core; this binding triggers the degradation of REQ mRNA and thus regulates translation. Furthermore, we demonstrate that siRNA-mediated silencing of either STAU1 or UPF1 increases the abundance of cellular REQ mRNA and, consequently, the REQ protein, indicating that REQ mRNA is a target of SMD.
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Affiliation(s)
- Min Young Kim
- Department of Life Science and Research Institute for Natural Sciences, College of Natural Sciences
| | - Jungyun Park
- Graduate School for Biomedical Science and Engineering, Hanyang University, Seoul 133-791, Korea
| | - Jong Joo Lee
- Department of Life Science and Research Institute for Natural Sciences, College of Natural Sciences
| | - Dae Hyun Ha
- Department of Life Science and Research Institute for Natural Sciences, College of Natural Sciences
| | - Jonghwan Kim
- Department of Life Science and Research Institute for Natural Sciences, College of Natural Sciences
| | - Chan Gil Kim
- Department of Biotechnology, Konkuk University, Chungju 380-701, Korea
| | - Jungwook Hwang
- Graduate School for Biomedical Science and Engineering, Hanyang University, Seoul 133-791, Korea
| | - Chul Geun Kim
- Department of Life Science and Research Institute for Natural Sciences, College of Natural Sciences
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14
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Hořejší Z, Stach L, Flower TG, Joshi D, Flynn H, Skehel JM, O'Reilly NJ, Ogrodowicz RW, Smerdon SJ, Boulton SJ. Phosphorylation-dependent PIH1D1 interactions define substrate specificity of the R2TP cochaperone complex. Cell Rep 2014; 7:19-26. [PMID: 24656813 PMCID: PMC3989777 DOI: 10.1016/j.celrep.2014.03.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 03/04/2014] [Accepted: 03/07/2014] [Indexed: 12/21/2022] Open
Abstract
The R2TP cochaperone complex plays a critical role in the assembly of multisubunit machines, including small nucleolar ribonucleoproteins (snoRNPs), RNA polymerase II, and the mTORC1 and SMG1 kinase complexes, but the molecular basis of substrate recognition remains unclear. Here, we describe a phosphopeptide binding domain (PIH-N) in the PIH1D1 subunit of the R2TP complex that preferentially binds to highly acidic phosphorylated proteins. A cocrystal structure of a PIH-N domain/TEL2 phosphopeptide complex reveals a highly specific phosphopeptide recognition mechanism in which Lys57 and 64 in PIH1D1, along with a conserved DpSDD phosphopeptide motif within TEL2, are essential and sufficient for binding. Proteomic analysis of PIH1D1 interactors identified R2TP complex substrates that are recruited by the PIH-N domain in a sequence-specific and phosphorylation-dependent manner suggestive of a common mechanism of substrate recognition. We propose that protein complexes assembled by the R2TP complex are defined by phosphorylation of a specific motif and recognition by the PIH1D1 subunit.
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Affiliation(s)
- Zuzana Hořejší
- DNA Damage Response Laboratory, London Research Institute, Clare Hall, South Mimms EN6 3LD, UK
| | - Lasse Stach
- MRC National Institute for Medical Research, Division of Molecular Structure, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Thomas G Flower
- MRC National Institute for Medical Research, Division of Molecular Structure, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Dhira Joshi
- Peptide Chemistry, London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Helen Flynn
- DNA Damage Response Laboratory, London Research Institute, Clare Hall, South Mimms EN6 3LD, UK
| | - J Mark Skehel
- DNA Damage Response Laboratory, London Research Institute, Clare Hall, South Mimms EN6 3LD, UK; Biological Mass Spectrometry and Proteomics Group, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Nicola J O'Reilly
- DNA Damage Response Laboratory, London Research Institute, Clare Hall, South Mimms EN6 3LD, UK
| | - Roksana W Ogrodowicz
- MRC National Institute for Medical Research, Division of Molecular Structure, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Stephen J Smerdon
- MRC National Institute for Medical Research, Division of Molecular Structure, The Ridgeway, Mill Hill, London NW7 1AA, UK.
| | - Simon J Boulton
- DNA Damage Response Laboratory, London Research Institute, Clare Hall, South Mimms EN6 3LD, UK.
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15
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Ahn S, Park J, An I, Jung SJ, Hwang J. Transient receptor potential cation channel V1 (TRPV1) is degraded by starvation- and glucocorticoid-mediated autophagy. Mol Cells 2014; 37:257-63. [PMID: 24658385 PMCID: PMC3969047 DOI: 10.14348/molcells.2014.2384] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/13/2014] [Accepted: 02/17/2014] [Indexed: 01/09/2023] Open
Abstract
A mammalian cell renovates itself by autophagy, a process through which cellular components are recycled to produce energy and maintain homeostasis. Recently, the abundance of gap junction proteins was shown to be regulated by autophagy during starvation conditions, suggesting that transmembrane proteins are also regulated by autophagy. Transient receptor potential vanilloid type 1 (TRPV1), an ion channel localized to the plasma membrane and endoplasmic reticulum (ER), is a sensory transducer that is activated by a wide variety of exogenous and endogenous physical and chemical stimuli. Intriguingly, the abundance of cellular TRPV1 can change dynamically under pathological conditions. However, the mechanisms by which the protein levels of TRPV1 are regulated have not yet been explored. Therefore, we investigated the mechanisms of TRPV1 recycling using HeLa cells constitutively expressing TRPV1. Endogenous TRPV1 was degraded in starvation conditions; this degradation was blocked by chloroquine (CLQ), 3MA, or downregulation of Atg7. Interestingly, a glucocorticoid (cortisol) was capable of inducing autophagy in HeLa cells. Cortisol increased cellular conversion of LC3-I to LC-3II, leading autophagy and resulting in TRPV1 degradation, which was similarly inhibited by treatment with CLQ, 3MA, or downregulation of Atg7. Furthermore, cortisol treatment induced the colocalization of GFP-LC3 with endogenous TRPV1. Cumulatively, these observations provide evidence that degradation of TRPV1 is mediated by autophagy, and that this pathway can be enhanced by cortisol.
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Affiliation(s)
- Seyoung Ahn
- Graduate School for Biomedical Science and Engineering, Hanyang University, Seoul 133-791,
Korea
| | - Jungyun Park
- Graduate School for Biomedical Science and Engineering, Hanyang University, Seoul 133-791,
Korea
| | - Inkyung An
- Graduate School for Biomedical Science and Engineering, Hanyang University, Seoul 133-791,
Korea
| | - Sung Jun Jung
- Department of Physiology, College of Medicine, Hanyang University, Seoul 133-791,
Korea
| | - Jungwook Hwang
- Graduate School for Biomedical Science and Engineering, Hanyang University, Seoul 133-791,
Korea
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