1
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Buchan JR. Stress granule and P-body clearance: Seeking coherence in acts of disappearance. Semin Cell Dev Biol 2024; 159-160:10-26. [PMID: 38278052 PMCID: PMC10939798 DOI: 10.1016/j.semcdb.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 01/07/2024] [Indexed: 01/28/2024]
Abstract
Stress granules and P-bodies are conserved cytoplasmic biomolecular condensates whose assembly and composition are well documented, but whose clearance mechanisms remain controversial or poorly described. Such understanding could provide new insight into how cells regulate biomolecular condensate formation and function, and identify therapeutic strategies in disease states where aberrant persistence of stress granules in particular is implicated. Here, I review and compare the contributions of chaperones, the cytoskeleton, post-translational modifications, RNA helicases, granulophagy and the proteasome to stress granule and P-body clearance. Additionally, I highlight the potentially vital role of RNA regulation, cellular energy, and changes in the interaction networks of stress granules and P-bodies as means of eliciting clearance. Finally, I discuss evidence for interplay of distinct clearance mechanisms, suggest future experimental directions, and suggest a simple working model of stress granule clearance.
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Affiliation(s)
- J Ross Buchan
- Department of Molecular and Cellular Biology, University of Arizona, Tucson 85716, United States.
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2
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Huber K, Giralt A, Dreos R, Michenthaler H, Geller S, Barquissau V, Ziegler DV, Tavernari D, Gallart-Ayala H, Krajina K, Jonas K, Ciriello G, Ivanisevic J, Prokesch A, Pichler M, Fajas L. E2F transcription factor-1 modulates expression of glutamine metabolic genes in mouse embryonic fibroblasts and uterine sarcoma cells. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119721. [PMID: 38580088 DOI: 10.1016/j.bbamcr.2024.119721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 03/12/2024] [Accepted: 03/27/2024] [Indexed: 04/07/2024]
Abstract
Metabolic reprogramming is considered as a hallmark of cancer and is clinically exploited as a novel target for therapy. The E2F transcription factor-1 (E2F1) regulates various cellular processes, including proliferative and metabolic pathways, and acts, depending on the cellular and molecular context, as an oncogene or tumor suppressor. The latter is evident by the observation that E2f1-knockout mice develop spontaneous tumors, including uterine sarcomas. This dual role warrants a detailed investigation of how E2F1 loss impacts metabolic pathways related to cancer progression. Our data indicate that E2F1 binds to the promoter of several glutamine metabolism-related genes. Interestingly, the expression of genes in the glutamine metabolic pathway were increased in mouse embryonic fibroblasts (MEFs) lacking E2F1. In addition, we confirm that E2f1-/- MEFs are more efficient in metabolizing glutamine and producing glutamine-derived precursors for proliferation. Mechanistically, we observe a co-occupancy of E2F1 and MYC on glutamine metabolic promoters, increased MYC binding after E2F1 depletion and that silencing of MYC decreased the expression of glutamine-related genes in E2f1-/- MEFs. Analyses of transcriptomic profiles in 29 different human cancers identified uterine sarcoma that showed a negative correlation between E2F1 and glutamine metabolic genes. CRISPR/Cas9 knockout of E2F1 in the uterine sarcoma cell line SK-UT-1 confirmed elevated glutamine metabolic gene expression, increased proliferation and increased MYC binding to glutamine-related promoters upon E2F1 loss. Together, our data suggest a crucial role of E2F1 in energy metabolism and metabolic adaptation in uterine sarcoma cells.
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Affiliation(s)
- Katharina Huber
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland; Division of Oncology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Albert Giralt
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - René Dreos
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Helene Michenthaler
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Division of Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria
| | - Sarah Geller
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Valentin Barquissau
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Dorian V Ziegler
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Daniele Tavernari
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland; Swiss Cancer Center Léman, Lausanne, Switzerland; Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Hector Gallart-Ayala
- Metabolomics Unit, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Katarina Krajina
- Division of Oncology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Katharina Jonas
- Division of Oncology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Giovanni Ciriello
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland; Swiss Cancer Center Léman, Lausanne, Switzerland; Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Julijana Ivanisevic
- Metabolomics Unit, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Andreas Prokesch
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Division of Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Martin Pichler
- Division of Oncology, Department of Internal Medicine, Medical University of Graz, Graz, Austria; Translational Oncology, II. Med. Clinics, University Hospital of Augsburg, Augsburg, Germany
| | - Lluis Fajas
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland.
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3
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Sun J, Xiang Q, Ding D, Yan N. USP10 suppresses ABCG2-induced malignant characteristics of doxorubicin-resistant thyroid cancer by inhibiting PI3K/AKT pathway. J Bioenerg Biomembr 2023; 55:457-466. [PMID: 37919637 PMCID: PMC10682060 DOI: 10.1007/s10863-023-09986-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/27/2023] [Indexed: 11/04/2023]
Abstract
Doxorubicin (DOX) is the most extensively used drug in the chemotherapy of thyroid cancer (TC). However, the existence of DOX resistance is not conducive to TC treatment. Here, we investigated the role of USP10 in DOX-resistant TC and explored the underlying molecular mechanism. CCK-8 assay was used to measure cell viability in thyroid cancer FTC133 and DOX-resistant FTC133-DOX cells. RT-qPCR and western blot were used to evaluate USP10 expression. Cell migration, invasion, and apoptotic assays were conducted. Western blot was used to detect cellular signaling proteins, EMT-related proteins, and apoptosis-related proteins. We found a lower expression of USP10 in the human TC cell line FTC133 as compared to the normal human thyroid Htori-3 cells. Notably, USP10 expression was further reduced in DOX-resistant (FTC133-DOX) cells compared to the FTC133 cells. FTC133-DOX cells had increased invasion, migration, and EMT properties while less apoptosis by activating the PI3K/AKT pathway. Interestingly, overexpressing USP10 increased the chemosensitivity of FTC133 cells to DOX therapy. Overexpressing USP10 inhibited invasion, migration, and EMT properties of FTC133-DOX cells and promoted apoptosis. Mechanistically, overexpressing USP10 inhibited PI3K/AKT pathway by activating PTEN. Furthermore, overexpressed USP10 controlled all these processes by downregulating ABCG2. This study demonstrates that USP10 could reduce DOX-induced resistance of TC cells to DOX therapy and could suppress TC malignant behavior by inhibiting the PI3K/AKT pathway. Furthermore, USP10 targeted ABCG2 to inhibit all these malignant processes, therefore, either increasing USP10 expression or inhibiting ABCG2 could be used as novel targets for treating DOX-resistant thyroid cancer.
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Affiliation(s)
- Jianwei Sun
- Department of Ultrasound, Fifth Affiliated Hospital of Kunming Medical University, 17 South Goldenlake Road, Gejiu, 661000, China
| | - Qian Xiang
- Department of Endocrinology, Fifth Affiliated Hospital of Kunming Medical University, 17 South Goldenlake Road, Gejiu, 661000, China
| | - Ding Ding
- Department of Ultrasound, Fifth Affiliated Hospital of Kunming Medical University, 17 South Goldenlake Road, Gejiu, 661000, China
| | - Nan Yan
- Department of Ultrasound, Fifth Affiliated Hospital of Kunming Medical University, 17 South Goldenlake Road, Gejiu, 661000, China.
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4
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Mukhopadhyay C, Zhou P. Role(s) of G3BPs in Human Pathogenesis. J Pharmacol Exp Ther 2023; 387:100-110. [PMID: 37468286 PMCID: PMC10519580 DOI: 10.1124/jpet.122.001538] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 06/28/2023] [Accepted: 07/11/2023] [Indexed: 07/21/2023] Open
Abstract
Ras-GTPase-activating protein (SH3 domain)-binding proteins (G3BP) are RNA binding proteins that play a critical role in stress granule (SG) formation. SGs protect critical mRNAs from various environmental stress conditions by regulating mRNA stability and translation to maintain regulated gene expression. Recent evidence suggests that G3BPs can also regulate mRNA expression through interactions with RNA outside of SGs. G3BPs have been associated with a number of disease states, including cancer progression, invasion, metastasis, and viral infections, and may be useful as a cancer therapeutic target. This review summarizes the biology of G3BP including their structure, function, localization, role in cancer progression, virus replication, mRNA stability, and SG formation. We will also discuss the potential of G3BPs as a therapeutic target. SIGNIFICANCE STATEMENT: This review will discuss the molecular mechanism(s) and functional role(s) of Ras-GTPase-activating protein (SH3 domain)-binding proteins in the context of stress granule formation, interaction with viruses, stability of RNA, and tumorigenesis.
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Affiliation(s)
- Chandrani Mukhopadhyay
- Department of Pathology and Laboratory Medicine, Weill Medical College of Cornell University, New York
| | - Pengbo Zhou
- Department of Pathology and Laboratory Medicine, Weill Medical College of Cornell University, New York
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5
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Ge Y, Jin J, Li J, Ye M, Jin X. The roles of G3BP1 in human diseases (review). Gene X 2022; 821:146294. [PMID: 35176431 DOI: 10.1016/j.gene.2022.146294] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/24/2022] [Accepted: 02/03/2022] [Indexed: 11/04/2022] Open
Abstract
Ras-GTPase-activating protein binding protein 1 (G3BP1) is a multifunctional binding protein involved in a variety of biological functions, including cell proliferation, metastasis, apoptosis, differentiation and RNA metabolism. It has been revealed that G3BP1, as an antiviral factor, can interact with viral proteins and regulate the assembly of stress granules (SGs), which can inhibit viral replication. Furthermore, several viruses have the ability to hijack G3BP1 as a cofactor, recruiting translation initiation factors to promote viral proliferation. However, many functions of G3BP1 are associated with other diseases. In various cancers, G3BP1 is a cancer-promoting factor, which can promote the proliferation, invasion and metastasis of cancer cells. Moreover, compared with normal tissues, G3BP1 expression is higher in tumor tissues, indicating that it can be used as an indicator for cancer diagnosis. In this review, the structure of G3BP1 and the regulation of G3BP1 in multiple dimensions are described. In addition, the effects and potential mechanisms of G3BP1 on various carcinomas, viral infections, nervous system diseases and cardiovascular diseases are elucidated, which may provide a direction for clinical applications of G3BP1 in the future.
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Affiliation(s)
- Yidong Ge
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo 315020, China; Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathphysiology, Medical School of Ningbo University, Ningbo 315211, China
| | - Jiabei Jin
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo 315020, China; Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathphysiology, Medical School of Ningbo University, Ningbo 315211, China
| | - Jinyun Li
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo 315020, China; Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathphysiology, Medical School of Ningbo University, Ningbo 315211, China
| | - Meng Ye
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo 315020, China; Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathphysiology, Medical School of Ningbo University, Ningbo 315211, China.
| | - Xiaofeng Jin
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo 315020, China; Department of Biochemistry and Molecular Biology, and Zhejiang Key Laboratory of Pathphysiology, Medical School of Ningbo University, Ningbo 315211, China.
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6
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Asadi MR, Moslehian MS, Sabaie H, Poornabi M, Ghasemi E, Hassani M, Hussen BM, Taheri M, Rezazadeh M. Stress Granules in the Anti-Cancer Medications Mechanism of Action: A Systematic Scoping Review. Front Oncol 2021; 11:797549. [PMID: 35004322 PMCID: PMC8739770 DOI: 10.3389/fonc.2021.797549] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/08/2021] [Indexed: 12/16/2022] Open
Abstract
Stress granule (SG) formation is a well-known cellular mechanism for minimizing stress-related damage and increasing cell survival. In addition to playing a critical role in the stress response, SGs have emerged as critical mediators in human health. It seems logical that SGs play a key role in cancer cell formation, development, and metastasis. Recent studies have shown that many SG components contribute to the anti-cancer medications' responses through tumor-associated signaling pathways and other mechanisms. SG proteins are known for their involvement in the translation process, control of mRNA stability, and capacity to function in both the cytoplasm and nucleus. The current systematic review aimed to include all research on the impact of SGs on the mechanism of action of anti-cancer medications and was conducted using a six-stage methodological framework and the PRISMA guideline. Prior to October 2021, a systematic search of seven databases for eligible articles was performed. Following the review of the publications, the collected data were subjected to quantitative and qualitative analysis. Notably, Bortezomib, Sorafenib, Oxaliplatin, 5-fluorouracil, Cisplatin, and Doxorubicin accounted for the majority of the medications examined in the studies. Overall, this systematic scoping review attempts to demonstrate and give a complete overview of the function of SGs in the mechanism of action of anti-cancer medications by evaluating all research.
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Affiliation(s)
- Mohammad Reza Asadi
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Hani Sabaie
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Marziye Poornabi
- Student Research Committee, School of Medicine, Shahroud University of Medical Science, Shahroud, Iran
| | - Elham Ghasemi
- Department of Molecular Medicine and Biotechnology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Mehdi Hassani
- Student Research Committee, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Bashdar Mahmud Hussen
- Department of Pharmacognosy, College of Pharmacy, Hawler Medical University, Erbil, Iraq
| | - Mohammad Taheri
- Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Institute of Human Genetics, Jena University Hospital, Jena, Germany
| | - Maryam Rezazadeh
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
- Clinical Research Development Unit of Tabriz Valiasr Hospital, Tabriz University of Medical Sciences, Tabriz, Iran
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7
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Trofimenko E, Homma Y, Fukuda M, Widmann C. The endocytic pathway taken by cationic substances requires Rab14 but not Rab5 and Rab7. Cell Rep 2021; 37:109945. [PMID: 34731620 DOI: 10.1016/j.celrep.2021.109945] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 08/23/2021] [Accepted: 10/13/2021] [Indexed: 02/01/2023] Open
Abstract
Endocytosis and endosome dynamics are controlled by proteins of the small GTPase Rab family. Besides possible recycling routes to the plasma membrane and various organelles, previously described endocytic pathways (e.g., clathrin-mediated endocytosis, macropinocytosis, CLIC/GEEC pathway) all appear to funnel the endocytosed material to Rab5-positive early endosomes that then mature into Rab7-positive late endosomes/lysosomes. By studying the uptake of a series of cell-penetrating peptides (CPPs), we identify an endocytic pathway that moves material to nonacidic Lamp1-positive late endosomes. Trafficking via this endocytic route is fully independent of Rab5 and Rab7 but requires the Rab14 protein. The pathway taken by CPPs differs from the conventional Rab5-dependent endocytosis at the stage of vesicle formation already, as it is not affected by a series of compounds that inhibit macropinocytosis or clathrin-mediated endocytosis. The Rab14-dependent pathway is also used by physiological cationic molecules such as polyamines and homeodomains found in homeoproteins.
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Affiliation(s)
- Evgeniya Trofimenko
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Yuta Homma
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Christian Widmann
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.
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8
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Kang W, Wang Y, Yang W, Zhang J, Zheng H, Li D. Research Progress on the Structure and Function of G3BP. Front Immunol 2021; 12:718548. [PMID: 34526993 PMCID: PMC8435845 DOI: 10.3389/fimmu.2021.718548] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/10/2021] [Indexed: 01/10/2023] Open
Abstract
Ras-GTPase-activating protein (SH3 domain)-binding protein (G3BP) is an RNA binding protein. G3BP is a key component of stress granules (SGs) and can interact with many host proteins to regulate the expression of SGs. As an antiviral factor, G3BP can interact with viral proteins to regulate the assembly of SGs and thus exert antiviral effects. However, many viruses can also use G3BP as a proximal factor and recruit translation initiation factors to promote viral proliferation. G3BP regulates mRNA translation and attenuation to regulate gene expression; therefore, it is closely related to diseases, such as cancer, embryonic death, arteriosclerosis, and neurodevelopmental disorders. This review discusses the important discoveries and developments related G3BP in the biological field over the past 20 years, which includes the formation of SGs, interaction with viruses, stability of RNA, and disease progression.
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Affiliation(s)
- Weifang Kang
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yue Wang
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Wenping Yang
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Jing Zhang
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Haixue Zheng
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Dan Li
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
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9
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Cuesta C, Arévalo-Alameda C, Castellano E. The Importance of Being PI3K in the RAS Signaling Network. Genes (Basel) 2021; 12:1094. [PMID: 34356110 PMCID: PMC8303222 DOI: 10.3390/genes12071094] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/06/2021] [Accepted: 07/16/2021] [Indexed: 12/12/2022] Open
Abstract
Ras proteins are essential mediators of a multitude of cellular processes, and its deregulation is frequently associated with cancer appearance, progression, and metastasis. Ras-driven cancers are usually aggressive and difficult to treat. Although the recent Food and Drug Administration (FDA) approval of the first Ras G12C inhibitor is an important milestone, only a small percentage of patients will benefit from it. A better understanding of the context in which Ras operates in different tumor types and the outcomes mediated by each effector pathway may help to identify additional strategies and targets to treat Ras-driven tumors. Evidence emerging in recent years suggests that both oncogenic Ras signaling in tumor cells and non-oncogenic Ras signaling in stromal cells play an essential role in cancer. PI3K is one of the main Ras effectors, regulating important cellular processes such as cell viability or resistance to therapy or angiogenesis upon oncogenic Ras activation. In this review, we will summarize recent advances in the understanding of Ras-dependent activation of PI3K both in physiological conditions and cancer, with a focus on how this signaling pathway contributes to the formation of a tumor stroma that promotes tumor cell proliferation, migration, and spread.
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Affiliation(s)
| | | | - Esther Castellano
- Tumour-Stroma Signalling Laboratory, Centro de Investigación del Cáncer, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain; (C.C.); (C.A.-A.)
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10
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Conde-Rubio MDC, Mylonas R, Widmann C. The proteolytic landscape of cells exposed to non-lethal stresses is shaped by executioner caspases. Cell Death Discov 2021; 7:164. [PMID: 34226511 PMCID: PMC8257705 DOI: 10.1038/s41420-021-00539-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/26/2021] [Accepted: 05/29/2021] [Indexed: 02/06/2023] Open
Abstract
Cells are in constant adaptation to environmental changes to insure their proper functioning. When exposed to stresses, cells activate specific pathways to elicit adaptive modifications. Those changes can be mediated by selective modulation of gene and protein expression as well as by post-translational modifications, such as phosphorylation and proteolytic processing. Protein cleavage, as a controlled and limited post-translational modification, is involved in diverse physiological processes such as the maintenance of protein homeostasis, activation of repair pathways, apoptosis and the regulation of proliferation. Here we assessed by quantitative proteomics the proteolytic landscape in two cell lines subjected to low cisplatin concentrations used as a mild non-lethal stress paradigm. This landscape was compared to the one obtained in the same cells stimulated with cisplatin concentrations inducing apoptosis. These analyses were performed in wild-type cells and in cells lacking the two main executioner caspases: caspase-3 and caspase-7. Ninety-two proteins were found to be cleaved at one or a few sites (discrete cleavage) in low stress conditions compared to four hundred and fifty-three in apoptotic cells. Many of the cleaved proteins in stressed cells were also found to be cleaved in apoptotic conditions. As expected, ~90% of the cleavage events were dependent on caspase-3/caspase-7 in apoptotic cells. Strikingly, upon exposure to non-lethal stresses, no discrete cleavage was detected in cells lacking caspase-3 and caspase-7. This indicates that the proteolytic landscape in stressed viable cells fully depends on the activity of executioner caspases. These results suggest that the so-called executioner caspases fulfill important stress adaptive responses distinct from their role in apoptosis. Mass spectrometry data are available via ProteomeXchange with identifier PXD023488.
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Affiliation(s)
| | - Roman Mylonas
- Protein Analysis Facility, University of Lausanne, Génopode, Lausanne, Switzerland.,SIB Swiss Institute of Bioinformatics, Amphipole, Lausanne, Switzerland
| | - Christian Widmann
- Department of Biomedical Sciences, University of Lausanne, Bugnon 7, Lausanne, Switzerland.
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11
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Sidibé H, Dubinski A, Vande Velde C. The multi-functional RNA-binding protein G3BP1 and its potential implication in neurodegenerative disease. J Neurochem 2021; 157:944-962. [PMID: 33349931 PMCID: PMC8248322 DOI: 10.1111/jnc.15280] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022]
Abstract
Ras-GTPase-activating protein (GAP)-binding protein 1 (G3BP1) is a multi-functional protein that is best known for its role in the assembly and dynamics of stress granules. Recent studies have highlighted that G3BP1 also has other functions related to RNA metabolism. In the context of disease, G3BP1 has been therapeutically targeted in cancers because its over-expression is correlated with proliferation of cancerous cells and metastasis. However, evidence suggests that G3BP1 is essential for neuronal development and possibly neuronal maintenance. In this review, we will examine the many functions that are carried out by G3BP1 in the context of neurons and speculate how these functions are critical to the progression of neurodegenerative diseases. Additionally, we will highlight the similarities and differences between G3BP1 and the closely related protein G3BP2, which is frequently overlooked. Although G3BP1 and G3BP2 have both been deemed important for stress granule assembly, their roles may differ in other cellular pathways, some of which are specific to the CNS, and presents an opportunity for further exploration.
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Affiliation(s)
- Hadjara Sidibé
- Department of NeurosciencesUniversité de Montréal, and CHUM Research CenterMontréalQCCanada
| | - Alicia Dubinski
- Department of NeurosciencesUniversité de Montréal, and CHUM Research CenterMontréalQCCanada
| | - Christine Vande Velde
- Department of NeurosciencesUniversité de Montréal, and CHUM Research CenterMontréalQCCanada
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12
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Porcine Epidemic Diarrhea Virus Infection Induces Caspase-8-Mediated G3BP1 Cleavage and Subverts Stress Granules To Promote Viral Replication. J Virol 2021; 95:JVI.02344-20. [PMID: 33568512 DOI: 10.1128/jvi.02344-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/03/2021] [Indexed: 12/19/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) is an α-coronavirus causing severe diarrhea and high mortality rates in suckling piglets and posing significant economic impact. PEDV replication is completed and results in a large amount of RNA in the cytoplasm. Stress granules (SGs) are dynamic cytosolic RNA granules formed under various stress conditions, including viral infections. Several previous studies suggested that SGs were involved in the antiviral activity of host cells to limit viral propagation. However, the underlying mechanisms are poorly understood. This study aimed to delineate the molecular mechanisms regulating the SG response to PEDV infection. SG formation is induced early during PEDV infection, but as infection proceeds, this ability is lost and SGs disappear at late stages of infection (>18 h postinfection). PEDV infection resulted in the cleavage of Ras-GTPase-activating protein-binding protein 1 (G3BP1) mediated by caspase-8. Using mutational analysis, the PEDV-induced cleavage site within G3BP1 was identified, which differed from the 3C protease cleavage site previously identified. Furthermore, G3BP1 cleavage by caspase-8 at D168 and D169 was confirmed in vitro as well as in vivo The overexpression of cleavage-resistant G3BP1 conferred persistent SG formation and suppression of viral replication. Additionally, the knockdown of endogenous G3BP1 abolished SG formation and potentiated viral replication. Taken together, these data provide new insights into novel strategies in which PEDV limits the host stress response and antiviral responses and indicate that caspase-8-mediated G3BP1 cleavage is important in the failure of host defense against PEDV infection.IMPORTANCE Coronaviruses (CoVs) are drawing extensive attention again since the outbreaks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019. CoVs are prone to variation and own the transmission capability by crossing the species barrier resulting in reemergence. How CoVs manipulate the antiviral responses of their hosts needs to be explored. Overall, the study provides new insight into how porcine epidemic diarrhea virus (PEDV) impaired SG assembly by targeting G3BP1 via the host proteinase caspase-8. These findings enhanced the understanding of PEDV infection and might help identify new antiviral targets that could inhibit viral replication and limit the pathogenesis of PEDV.
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13
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Prentzell MT, Rehbein U, Cadena Sandoval M, De Meulemeester AS, Baumeister R, Brohée L, Berdel B, Bockwoldt M, Carroll B, Chowdhury SR, von Deimling A, Demetriades C, Figlia G, de Araujo MEG, Heberle AM, Heiland I, Holzwarth B, Huber LA, Jaworski J, Kedra M, Kern K, Kopach A, Korolchuk VI, van 't Land-Kuper I, Macias M, Nellist M, Palm W, Pusch S, Ramos Pittol JM, Reil M, Reintjes A, Reuter F, Sampson JR, Scheldeman C, Siekierska A, Stefan E, Teleman AA, Thomas LE, Torres-Quesada O, Trump S, West HD, de Witte P, Woltering S, Yordanov TE, Zmorzynska J, Opitz CA, Thedieck K. G3BPs tether the TSC complex to lysosomes and suppress mTORC1 signaling. Cell 2021; 184:655-674.e27. [PMID: 33497611 PMCID: PMC7868890 DOI: 10.1016/j.cell.2020.12.024] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 11/03/2020] [Accepted: 12/14/2020] [Indexed: 12/22/2022]
Abstract
Ras GTPase-activating protein-binding proteins 1 and 2 (G3BP1 and G3BP2, respectively) are widely recognized as core components of stress granules (SGs). We report that G3BPs reside at the cytoplasmic surface of lysosomes. They act in a non-redundant manner to anchor the tuberous sclerosis complex (TSC) protein complex to lysosomes and suppress activation of the metabolic master regulator mechanistic target of rapamycin complex 1 (mTORC1) by amino acids and insulin. Like the TSC complex, G3BP1 deficiency elicits phenotypes related to mTORC1 hyperactivity. In the context of tumors, low G3BP1 levels enhance mTORC1-driven breast cancer cell motility and correlate with adverse outcomes in patients. Furthermore, G3bp1 inhibition in zebrafish disturbs neuronal development and function, leading to white matter heterotopia and neuronal hyperactivity. Thus, G3BPs are not only core components of SGs but also a key element of lysosomal TSC-mTORC1 signaling.
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Affiliation(s)
- Mirja Tamara Prentzell
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department of Bioinformatics and Molecular Genetics (Faculty of Biology), University of Freiburg, Freiburg 79104, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg 79104, Germany
| | - Ulrike Rehbein
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Marti Cadena Sandoval
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Ann-Sofie De Meulemeester
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium
| | - Ralf Baumeister
- Department of Bioinformatics and Molecular Genetics (Faculty of Biology), University of Freiburg, Freiburg 79104, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg 79104, Germany; Signalling Research Centres BIOSS and CIBSS & ZBMZ Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, Freiburg 79104, Germany
| | - Laura Brohée
- Cell Growth Control in Health and Age-Related Disease Group, Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne 50931, Germany
| | - Bianca Berdel
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Mathias Bockwoldt
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø 9037, Norway
| | - Bernadette Carroll
- School of Biochemistry, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Suvagata Roy Chowdhury
- Cell Signaling and Metabolism Group, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Andreas von Deimling
- German Consortium of Translational Cancer Research (DKTK), Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Neuropathology, Institute of Pathology, Heidelberg University, Heidelberg 69120, Germany
| | - Constantinos Demetriades
- Cell Growth Control in Health and Age-Related Disease Group, Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne 50931, Germany; CECAD Cluster of Excellence, University of Cologne, Cologne 50931, Germany
| | - Gianluca Figlia
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Heidelberg University, Heidelberg 69120, Germany
| | | | - Alexander M Heberle
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Ines Heiland
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø 9037, Norway
| | - Birgit Holzwarth
- Department of Bioinformatics and Molecular Genetics (Faculty of Biology), University of Freiburg, Freiburg 79104, Germany
| | - Lukas A Huber
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria; Austrian Drug Screening Institute (ADSI), Innsbruck 6020, Austria
| | - Jacek Jaworski
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Magdalena Kedra
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Katharina Kern
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Andrii Kopach
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Viktor I Korolchuk
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Ineke van 't Land-Kuper
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany
| | - Matylda Macias
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam 3015 GD, The Netherlands
| | - Wilhelm Palm
- Cell Signaling and Metabolism Group, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Stefan Pusch
- German Consortium of Translational Cancer Research (DKTK), Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Neuropathology, Institute of Pathology, Heidelberg University, Heidelberg 69120, Germany
| | - Jose Miguel Ramos Pittol
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Michèle Reil
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Anja Reintjes
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Friederike Reuter
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Julian R Sampson
- Institute of Medical Genetics, Division of Cancer and Genetics, Cardiff University Medical School, Cardiff CF14 4AY, UK
| | - Chloë Scheldeman
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium; Neurogenetics Research Group, VUB, Brussels 1090, Belgium
| | - Aleksandra Siekierska
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium
| | - Eduard Stefan
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Aurelio A Teleman
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Heidelberg University, Heidelberg 69120, Germany
| | - Laura E Thomas
- Institute of Life Science, Swansea University, Swansea SA2 8PP, UK
| | - Omar Torres-Quesada
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Saskia Trump
- Molecular Epidemiology Unit, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Berlin 13353, Germany
| | - Hannah D West
- Institute of Medical Genetics, Division of Cancer and Genetics, Cardiff University Medical School, Cardiff CF14 4AY, UK
| | - Peter de Witte
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium
| | - Sandra Woltering
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Teodor E Yordanov
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria; Division of Cell and Developmental Biology, Institute for Molecular Bioscience, University of Queensland, St Lucia QLD 4072, Australia
| | - Justyna Zmorzynska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Christiane A Opitz
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Neurology, University Hospital Heidelberg and National Center for Tumor Diseases, Heidelberg 69120, Germany.
| | - Kathrin Thedieck
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria.
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14
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Cloux AJ, Aubry D, Heulot M, Widmann C, ElMokh O, Piacente F, Cea M, Nencioni A, Bellotti A, Bouzourène K, Pellegrin M, Mazzolai L, Duchosal MA, Nahimana A. Reactive oxygen/nitrogen species contribute substantially to the antileukemia effect of APO866, a NAD lowering agent. Oncotarget 2019; 10:6723-6738. [PMID: 31803365 PMCID: PMC6877101 DOI: 10.18632/oncotarget.27336] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 11/07/2019] [Indexed: 02/03/2023] Open
Abstract
APO866 is a small molecule drug that specifically inhibits nicotinamide phosphoribosyltransferase (NAMPT), a key enzyme involved in nicotinamide adenine dinucleotide (NAD) biosynthesis from the natural precursor nicotinamide. Although, the antitumor activity of APO866 on various types of cancer models has been reported, information regarding mechanisms by which APO866 exerts its cytotoxic effects is not well defined. Here we show that APO866 induces a strong, time-dependent increase in highly reactive ROS, nitric oxide, cytosolic/mitochondrial superoxide anions and hydrogen peroxide. We provide evidence that APO866-mediated ROS production is modulated by PARP1 and triggers cell death through mitochondria depolarization and ATP loss. Genetic or pharmacologic inhibition of PARP1 prevented hydrogen peroxide accumulation, caspase activation, mitochondria depolarization, ATP loss and abrogates APO866-induced cell death, suggesting that the integrity of PARP1 status is required for cell death. Conversely, PARP1 activating drugs enhanced the anti-leukemia activity of APO866 Collectively, our studies show that APO866 induces ROS/RNS productions, which mediate its anti-leukemia effect. These results support testing new combinatorial strategies to enhance the antitumor activities of APO866.
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Affiliation(s)
- Anne-Julie Cloux
- Central Laboratory of Hematology, University Hospital of Lausanne, Lausanne, Switzerland
| | - Dominique Aubry
- Central Laboratory of Hematology, University Hospital of Lausanne, Lausanne, Switzerland
| | - Mathieu Heulot
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Christian Widmann
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Oussama ElMokh
- Central Laboratory of Hematology, University Hospital of Lausanne, Lausanne, Switzerland
| | | | - Michele Cea
- Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Alessio Nencioni
- Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Axel Bellotti
- Central Laboratory of Hematology, University Hospital of Lausanne, Lausanne, Switzerland
| | - Karima Bouzourène
- Division of Angiology, Heart and Vessel Department, Lausanne University Hospital, Lausanne, Switzerland
| | - Maxime Pellegrin
- Division of Angiology, Heart and Vessel Department, Lausanne University Hospital, Lausanne, Switzerland
| | - Lucia Mazzolai
- Division of Angiology, Heart and Vessel Department, Lausanne University Hospital, Lausanne, Switzerland
| | - Michel A Duchosal
- Central Laboratory of Hematology, University Hospital of Lausanne, Lausanne, Switzerland.,Service of Hematology, University Hospital of Lausanne, Lausanne, Switzerland
| | - Aimable Nahimana
- Central Laboratory of Hematology, University Hospital of Lausanne, Lausanne, Switzerland
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15
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Zhang LN, Zhao L, Yan XL, Huang YH. Loss of G3BP1 suppresses proliferation, migration, and invasion of esophageal cancer cells via Wnt/β-catenin and PI3K/AKT signaling pathways. J Cell Physiol 2019; 234:20469-20484. [PMID: 30989663 DOI: 10.1002/jcp.28648] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 03/21/2019] [Accepted: 03/25/2019] [Indexed: 01/06/2023]
Abstract
Accumulating evidence suggests that Ras GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is very crucial to regulate tumorigenesis and metastasis. Recently, many research works have suggested that G3BP1 is overexpressed in many human cancers including esophageal cancer. Nevertheless, the functional roles of G3BP1 in esophageal cancer are still unknown. Here, the results suggested that silencing of G3BP1 inhibited proliferation, migration, and invasion of esophageal cancer cells, whereas overexpression of G3BP1 led to opposite effects on the growth and metastasis. Surprisingly, G3BP1-depletion had no effect on cell death but caused the arrest of cell cycle in the G0 /G1 phase and increased the levels of p53 and p21. In addition, loss of G3BP1 led to a significant elevation of E-cadherin and decrease of N-cadherin, Vimentin, Snail, MMP-9, and MMP-2. Mechanistically, loss of G3BP1 dramatically suppressed Wnt-stimulated T-cell factor/lymphoid enhancer factor (TCF/LEF) transcription factor activity and downregulated its target genes including c-Myc, Axin2, and cyclin D1. Moreover, knockdown of G3BP1 downregulated the expression levels of p-PI3K, p-AKT, and p-GSK-3β, but the total PI3K, AKT, and GSK-3β were not changed. Furthermore, our data proved that the promoting effects of G3BP1-overexpression on cell proliferation, migration, and invasion could be rescued by PI3K inhibitor LY294002 treatment. Collectively, our results here elucidate that G3BP1-depletion suppresses proliferation, migration, and invasion capabilities of esophageal cancer cells via the inactivation of Wnt/β-catenin and PI3K/AKT signaling pathways. Furthermore, our findings imply that G3BP1 can participate in the regulation of esophageal cancer progression, and will be taken as a promising target to treat esophageal cancer.
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Affiliation(s)
- Li-Na Zhang
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, P. R. China
| | - Lei Zhao
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, P. R. China
| | - Xin-Long Yan
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, P. R. China
| | - Ying-Hui Huang
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, P. R. China
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16
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Identification of Clotrimazole Derivatives as Specific Inhibitors of Arenavirus Fusion. J Virol 2019; 93:JVI.01744-18. [PMID: 30626681 DOI: 10.1128/jvi.01744-18] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 12/21/2018] [Indexed: 02/06/2023] Open
Abstract
Arenaviruses are a large family of emerging enveloped negative-strand RNA viruses that include several causative agents of viral hemorrhagic fevers. For cell entry, human-pathogenic arenaviruses use different cellular receptors and endocytic pathways that converge at the level of acidified late endosomes, where the viral envelope glycoprotein mediates membrane fusion. Inhibitors of arenavirus entry hold promise for therapeutic antiviral intervention and the identification of "druggable" targets is of high priority. Using a recombinant vesicular stomatitis virus pseudotype platform, we identified the clotrimazole-derivative TRAM-34, a highly selective antagonist of the calcium-activated potassium channel KCa3.1, as a specific entry inhibitor for arenaviruses. TRAM-34 specifically blocked entry of most arenaviruses, including hemorrhagic fever viruses, but not Lassa virus and other enveloped viruses. Anti-arenaviral activity was likewise observed with the parental compound clotrimazole and the derivative senicapoc, whereas structurally unrelated KCa3.1 inhibitors showed no antiviral effect. Deletion of KCa3.1 by CRISPR/Cas9 technology did not affect the antiarenaviral effect of TRAM-34, indicating that the observed antiviral effect of clotrimazoles was independent of the known pharmacological target. The drug affected neither virus-cell attachment, nor endocytosis, suggesting an effect on later entry steps. Employing a quantitative cell-cell fusion assay that bypasses endocytosis, we demonstrate that TRAM-34 specifically inhibits arenavirus-mediated membrane fusion. In sum, we uncover a novel antiarenaviral action of clotrimazoles that currently undergo in vivo evaluation in the context of other human diseases. Their favorable in vivo toxicity profiles and stability opens the possibility to repurpose clotrimazole derivatives for therapeutic intervention against human-pathogenic arenaviruses.IMPORTANCE Emerging human-pathogenic arenaviruses are causative agents of severe hemorrhagic fevers with high mortality and represent serious public health problems. The current lack of a licensed vaccine and the limited treatment options makes the development of novel antiarenaviral therapeutics an urgent need. Using a recombinant pseudotype platform, we uncovered that clotrimazole drugs, in particular TRAM-34, specifically inhibit cell entry of a range of arenaviruses, including important emerging human pathogens, with the exception of Lassa virus. The antiviral effect was independent of the known pharmacological drug target and involved inhibition of the unusual membrane fusion mechanism of arenaviruses. TRAM-34 and its derivatives currently undergo evaluation against a number of human diseases and show favorable toxicity profiles and high stability in vivo Our study provides the basis for further evaluation of clotrimazole derivatives as antiviral drug candidates. Their advanced stage of drug development will facilitate repurposing for therapeutic intervention against human-pathogenic arenaviruses.
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17
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Zhang CH, Wang JX, Cai ML, Shao R, Liu H, Zhao WL. The roles and mechanisms of G3BP1 in tumour promotion. J Drug Target 2018; 27:300-305. [PMID: 30207743 DOI: 10.1080/1061186x.2018.1523415] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is a SH3 domain-binding protein that is overexpressed in a variety of tumour tissues and cancers, such as head and neck cancer, lung cancer, prostate cancer, colon cancer and breast cancer. G3BP1 promotes tumour cell proliferation and metastasis and inhibits apoptosis by regulating the Ras, TGF-β/Smad, Src/FAK and p53 signalling pathways. At present, polypeptides targeting G3BP1 have shown anti-tumour activity and G3BP1 also involved in anti-cancer effects of some polyphenolic compounds (resveratrol and EGCG). Therefore G3BP1 may be a potential target for tumour treatment.
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Affiliation(s)
- Cong-Hui Zhang
- a NHC Key Laboratory of Biotechnology of Antibiotics , Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences , Beijing , China
| | - Jun-Xia Wang
- a NHC Key Laboratory of Biotechnology of Antibiotics , Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences , Beijing , China
| | - Mei-Lian Cai
- a NHC Key Laboratory of Biotechnology of Antibiotics , Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences , Beijing , China
| | - Rongguang Shao
- a NHC Key Laboratory of Biotechnology of Antibiotics , Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences , Beijing , China
| | - Hong Liu
- a NHC Key Laboratory of Biotechnology of Antibiotics , Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences , Beijing , China
| | - Wu-Li Zhao
- a NHC Key Laboratory of Biotechnology of Antibiotics , Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences , Beijing , China
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18
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Rasputin a decade on and more promiscuous than ever? A review of G3BPs. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:360-370. [PMID: 30595162 PMCID: PMC7114234 DOI: 10.1016/j.bbamcr.2018.09.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/29/2018] [Accepted: 09/04/2018] [Indexed: 12/12/2022]
Abstract
Ras-GTPase-activating protein (SH3 domain)-binding proteins (G3BPs, also known as Rasputin) are a family of RNA binding proteins that regulate gene expression in response to environmental stresses by controlling mRNA stability and translation. G3BPs appear to facilitate this activity through their role in stress granules for which they are considered a core component, however, it should be noted that not all stress granules contain G3BPs and this appears to be contextual depending on the environmental stress and the cell type. Although the role of G3BPs in stress granules appears to be one of its major roles, data also strongly suggests that they interact with mRNAs outside of stress granules to regulate gene expression. G3BPs have been implicated in several diseases including cancer progression, invasion, and metastasis as well as virus survival. There is now a body of evidence that suggests targeting of G3BPs could be explored as a form of cancer therapeutic. This review discusses the important discoveries and advancements made in the field of G3BPs biology over the last two decades including their roles in RNA stability, translational control of cellular transcripts, stress granule formation, cancer progression and its interactions with viruses during infection. An emerging theme for G3BPs is their ability to regulate gene expression in response to environmental stimuli, disease progression and virus infection making it an intriguing target for disease therapies. Triage of many cellular mRNA occurs via stress granules in a G3BP-dependant manner. G3BPs control intra cellular responses to viral infection. Transcript stability, degradation and translation are controlled by G3BPs. G3BPs can control cancer progression.
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19
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Wang Y, Fu D, Chen Y, Su J, Wang Y, Li X, Zhai W, Niu Y, Yue D, Geng H. G3BP1 promotes tumor progression and metastasis through IL-6/G3BP1/STAT3 signaling axis in renal cell carcinomas. Cell Death Dis 2018; 9:501. [PMID: 29717134 PMCID: PMC5931548 DOI: 10.1038/s41419-018-0504-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/18/2018] [Accepted: 03/20/2018] [Indexed: 12/12/2022]
Abstract
The chronic inflammatory microenvironment within or surrounding the primary renal cell carcinoma (RCC) site promotes oncogenic transformation as well as contributes to the development of metastasis. G3BP stress granule assembly factor 1 (G3BP1) was found to be involved in the regulation of multiple cellular functions. However, its functions in RCC have not been previously explored. Here, we first showed that the expression of G3BP1 is elevated in human RCC and correlates with RCC progression. In cultured RCC cells, knockdown of G3BP1 results in inhibition of tumor cell proliferation, migration, and invasion, consistently with the alteration of epithelial–mesenchymal transition (EMT) and cell proliferative markers, including Cadherins, Vimentin, Snail, Slug, c-Myc, and cyclin D1. Remarkably, knockdown of G3BP1 dramatically impaired the signaling connection of pro-inflammatory cytokine IL-6 stimulation and downstream STAT3 activation in RCC, thus eventually contributing to the disruption of IL-6-elicited RCC migration and metastasis. In addition, in vivo orthotopic tumor xenografts results confirmed that knockdown of G3BP1 suppressed RCC tumor growth and metastasis in mice. Collectively, our findings support the notion that G3BP1 promotes tumor progression and metastasis through IL-6/G3BP1/STAT3 signaling axis in RCC.
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Affiliation(s)
- Yong Wang
- Department of Urology, The Second Hospital of Tianjin Medical University, Tianjin Institute of Urology, Tianjin Medical University, Tianjin, 300211, China
| | - Donghe Fu
- Department of Microbiology, School of Medical Laboratory, Tianjin Medical University, Tianjin, 300203, China
| | - Yajing Chen
- Research Center of Molecular Biology, Inner Mongolia Medical University, Hohhot, 010059, China
| | - Jing Su
- Department of Microbiology, School of Medical Laboratory, Tianjin Medical University, Tianjin, 300203, China.,Research Center of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Yiting Wang
- Department of Microbiology, School of Medical Laboratory, Tianjin Medical University, Tianjin, 300203, China.,Research Center of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Xin Li
- Department of Pharmacology, Tianjin Medical University, Tianjin, 300070, China
| | - Wei Zhai
- Department of Urology, Renji Hospital, School of Medicine in Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Yuanjie Niu
- Department of Urology, The Second Hospital of Tianjin Medical University, Tianjin Institute of Urology, Tianjin Medical University, Tianjin, 300211, China
| | - Dan Yue
- Department of Microbiology, School of Medical Laboratory, Tianjin Medical University, Tianjin, 300203, China.
| | - Hua Geng
- Research Center of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China.
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20
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Mammalian Orthoreovirus Factories Modulate Stress Granule Protein Localization by Interaction with G3BP1. J Virol 2017; 91:JVI.01298-17. [PMID: 28794026 DOI: 10.1128/jvi.01298-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 08/03/2017] [Indexed: 01/28/2023] Open
Abstract
Mammalian orthoreovirus (MRV) infection induces phosphorylation of translation initiation factor eIF2α, which promotes the formation of discrete cytoplasmic inclusions, termed stress granules (SGs). SGs are emerging as a component of the innate immune response to virus infection, and modulation of SG assembly is a common mechanism employed by viruses to counter this antiviral response. We previously showed that MRV infection induces SGs early and then interferes with SG formation as infection proceeds. In this work, we found that SG-associated proteins localized to the periphery of virus-encoded cytoplasmic structures, termed virus factories (VFs), where viral transcription, translation, and replication occur. The localization of SG proteins to VFs was dependent on polysome dissociation and occurred via association of the SG effector protein, Ras-GAP SH3-binding protein 1 (G3BP1), with the MRV nonstructural protein σNS, which localizes to VFs via association with VF nucleating protein, μNS. Deletion analysis of the σNS RNA binding domain and G3BP1 RNA (RRM) and ribosomal (RGG) binding domains showed that σNS association and VF localization phenotypes of G3BP1 do not occur solely through RNA or ribosomal binding but require both the RRM and RGG domains of G3BP1 for maximal viral-factory-like structure (VFL) localization and σNS association. Coexpression of σNS and μNS resulted in disruption of normal SG puncta, and in cells lacking G3BP1, MRV replication was enhanced in a manner correlating with strain-dependent induction of host translation shutoff. These results suggest that σNS association with G3BP1 and relocalization of G3BP1 to the VF periphery play roles in SG disruption to facilitate MRV replication in the host translational shutoff environment.IMPORTANCE SGs and SG effector proteins have emerged as important, yet poorly understood, players in the host's innate immune response to virus infection. MRV infection induces SGs early during infection that are dispersed and/or prevented from forming during late stages of infection despite continued activation of the eIF2α signaling pathway. Cellular and viral components involved in disruption of SGs during late stages of MRV infection remain to be elucidated. This work provides evidence that MRV disruption of SGs may be facilitated by association of the MRV nonstructural protein σNS with the major SG effector protein G3BP1 and subsequent localization of G3BP1 and other SG-associated proteins around the peripheries of virus-encoded factories, interrupting the normal formation of SGs. Our findings also reveal the importance of G3BP1 as an inhibitor of MRV replication during infection for the first time.
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21
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Beheshtizadeh M, Moslemi E. Analysis of G3BP1 and VEZT Expression in Gastric Cancer and Their Possible Correlation with Tumor Clinicopathological Factors. J Gastric Cancer 2017; 17:43-51. [PMID: 28337362 PMCID: PMC5362833 DOI: 10.5230/jgc.2017.17.e5] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/04/2017] [Accepted: 03/04/2017] [Indexed: 12/21/2022] Open
Abstract
Purpose This study aimed to analyze G3BP1 and VEZT expression profiles in patients with gastric cancer, and examine the possible relationship between the expressions of each gene and clinicopathological factors. Materials and Methods Expression of these genes in formalin-fixed paraffin embedded (FFPE) tissues, collected from 40 patients with gastric cancer and 40 healthy controls, was analyzed. Differences in gene expression among patient and normal samples were identified using the GraphPad Prism 5 software. For the analysis of real-time polymerase chain reaction products, GelQuantNET software was used. Results Our findings demonstrated that both VEZT and G3BP1 mRNA expression levels were downregulated in gastric cancer samples compared with those in the normal controls. No significant relationship was found between the expression of these genes and gender (P-value, 0.4835 vs. 0.6350), but there were significant changes associated with age (P-value, 0.0004 vs. 0.0001) and stage of disease (P-value, 0.0019 vs. 0.0001). In addition, there was a direct relationship between VEZT gene expression and metastasis (P-value, 0.0462), in contrast to G3BP1 that did not demonstrate any significant correlation (P-value, 0.1833). Conclusions The results suggest that expression profiling of VEZT and G3BP1 can be used for diagnosis of gastric cancer, and specifically, VEZT gene could be considered as a biomarker for the detection of gastric cancer progression.
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Affiliation(s)
| | - Elham Moslemi
- Department of Biology, East Tehran Branch, Islamic Azad University, Tehran, Iran
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22
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Tsoutsou P, Annibaldi A, Viertl D, Ollivier J, Buchegger F, Vozenin MC, Bourhis J, Widmann C, Matzinger O. TAT-RasGAP 317-326 Enhances Radiosensitivity of Human Carcinoma Cell Lines In Vitro and In Vivo through Promotion of Delayed Mitotic Cell Death. Radiat Res 2017; 187:562-569. [PMID: 28323576 DOI: 10.1667/rr14509.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The synthetic peptide TAT-RasGAP317-326 has been shown to potentiate the efficacy of anti-cancer drugs. In this study, we explored the action of TAT-RasGAP317-326 when combined with radiation by investigating its radiosensitizing activity in vitro and in vivo. To investigate the modulation of intrinsic radiosensitivity induced by TAT-RasGAP317-326, clonogenic assays were performed using four human cancer cell lines, HCT116 p53+/+ (ATCC: CCL-247), HCT116 p53-/-, PANC-1 (ATCC: CRL-1469) and HeLa (ATCC: CCL-2), as well as one nontumor cell line, HaCaT (CLS: 300493). Next, to investigate tumor growth delay after irradiation, HCT116 cell lines were selected and xenografted onto nude mice that were then treated with TAT-RasGAP317-326 alone or in combination with radiation or cisplatin. Afterwards, cell cycle and death modulation were investigated by quantification of micronuclei and apoptosis-related protein array. TAT-RasGAP317-326 radiosensitized all four human carcinoma cell lines tested but displayed no effect on normal cells. It also displayed no effect when administered as monotherapy. This radiosensitizing effect was confirmed in vivo in both p53-positive and p53-negative HCT116 xenografts. TAT-RasGAP317-326 combined with radiation enhanced the number of cells in S phase and subsequently delayed cell death, but had almost no effect on major apoptosis-related proteins. TAT-RasGAP317-326 is a radiosensitizing agent that acts on carcinoma cells and its radiosensitizing effect might be mediated, at least in part, by the enhancement of mitotic cell death.
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Affiliation(s)
- Pelagia Tsoutsou
- Department of a Radiation Oncology, Lausanne University Hospital, Lausanne, Switzerland.,c Laboratoire de Radio-Oncologie, CHUV, Lausanne, Switzerland.,e Department of Radiation Oncology, Hôpital Neuchâtelois, La Chaux-de-Fonds, Switzerland
| | | | - David Viertl
- Department of a Radiation Oncology, Lausanne University Hospital, Lausanne, Switzerland.,b Department of Nuclear Medicine, Lausanne University Hospital, Lausanne, Switzerland.,c Laboratoire de Radio-Oncologie, CHUV, Lausanne, Switzerland
| | | | - Franz Buchegger
- b Department of Nuclear Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | | | - Jean Bourhis
- Department of a Radiation Oncology, Lausanne University Hospital, Lausanne, Switzerland
| | - Christian Widmann
- d Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Oscar Matzinger
- Department of a Radiation Oncology, Lausanne University Hospital, Lausanne, Switzerland
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23
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Vanli G, Sempoux C, Widmann C. The caspase-3/p120 RasGAP stress-sensing module reduces liver cancer incidence but does not affect overall survival in gamma-irradiated and carcinogen-treated mice. Mol Carcinog 2017; 56:1680-1684. [PMID: 28150874 DOI: 10.1002/mc.22624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 01/25/2017] [Indexed: 11/08/2022]
Abstract
Activation of oncogenes is the initial step in cellular transformation. Oncogenes favor aberrant proliferation, which, at least initially, induces cellular stress. This oncogenic stress can act as a safeguard mechanism against further transformation by inducing senescence or apoptosis. Yet, the few premalignant cells that tolerate and escape these senescent or apoptotic responses are those that will ultimately generate tumors. The caspase-3/p120 RasGAP module is a stress-sensing device that promotes survival under mild stress conditions. A point mutation in RasGAP that prevents its cleavage by caspase-3 inactivates the pro-survival capacity of the device. When the mice homozygous for this mutation (D455A knock-in mice) are patho-physiologically challenged, they experience much stronger cellular damage than their wild-type counterparts and the affected organs rapidly lose their functionality. We reasoned that the caspase-3/p120 RasGAP module could help premalignant cells to cope with oncogenic stress and hence favor the development of tumors. Using gamma-irradiation and N-ethyl-N-nitrosourea (ENU) as tumor initiators, we assessed the survival advantage that the caspase-3/p120 RasGAP module could provide to premalignant cells. No difference in overall mortality between wild-type and D455A knock-in mice were observed. However, the number of ENU-induced liver tumors in the knock-in mice was higher than in control mice. These results indicate that the caspase-3/p120 RasGAP stress-sensing module impacts on carcinogen-induced liver cancer incidence but not sufficiently so as to affect overall survival. Hence, gamma irradiation and ENU-induced tumorigenesis processes do not critically rely on a survival mechanism that contributes to the maintenance of organ homeostasis in stressed healthy tissues.
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Affiliation(s)
- Güliz Vanli
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Christine Sempoux
- Institute of Pathology, University of Lausanne, Lausanne, Switzerland
| | - Christian Widmann
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
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24
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Tao Y, Hu K, Tan F, Zhang S, Zhou M, Luo J, Wang Z. SH3-domain binding protein 1 in the tumor microenvironment promotes hepatocellular carcinoma metastasis through WAVE2 pathway. Oncotarget 2017; 7:18356-70. [PMID: 26933917 PMCID: PMC4951293 DOI: 10.18632/oncotarget.7786] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Accepted: 02/11/2016] [Indexed: 02/06/2023] Open
Abstract
SH3-domain binding protein-1 (SH3BP1) specifically inactivating Rac1 and its target WAVE2 is required for cell motility. The present study shows SH3BP1 expression patterns in human HCC tissues and cell lines were examined. The regulation of SH3BP1 on HCC cell migration and invasion related to Rac1-WAVE2 signaling was characterized using in vitro and in vivo models. SH3BP1 overexpressed in HCC tissues and highly metastatic HCC cells was significantly associated vascular invasion (VI). SH3BP1 promoted VEGF secretion via Rac1-WAVE2 signaling, so as to exert an augmentation on cell invasion and microvessel formation. In three study cohorts with a total of 516 HCC patients, high SH3BP1 expression combined with high microvessel density (MVD) was confirmed as a powerful independent predictor of HCC prognosis in both training cohorts and validation cohort. Being an important angiogenic factor of HCC through Rac1-WAVE2 signaling, SH3BP1 promotes tumor invasion and microvessel formation contributing to HCC metastasis and recurrence. SH3BP1 is a novel WAVE2 regulator, a prognostic marker and a potential therapeutic target of HCC.
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Affiliation(s)
- Yiming Tao
- Department of Hepatobiliary Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Kuan Hu
- Department of Hepatobiliary Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Fengbo Tan
- Department of Hepatobiliary Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Sai Zhang
- Institute of Medical Sciences, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ming Zhou
- Institute of Cancer Research, Central South University, Changsha, Hunan, China
| | - Jia Luo
- Department of Hepatobiliary Surgery, Hunan Provincial Tumor Hospital, Changsha, Hunan, China
| | - Zhiming Wang
- Department of Hepatobiliary Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
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25
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Casein Kinase 2 Is Linked to Stress Granule Dynamics through Phosphorylation of the Stress Granule Nucleating Protein G3BP1. Mol Cell Biol 2017; 37:MCB.00596-16. [PMID: 27920254 DOI: 10.1128/mcb.00596-16] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 11/29/2016] [Indexed: 12/27/2022] Open
Abstract
Stress granules (SGs) are large macromolecular aggregates that contain translation initiation complexes and mRNAs. Stress granule formation coincides with translational repression, and stress granules actively signal to mediate cell fate decisions by signaling to the translation apparatus to (i) maintain translational repression, (ii) mount various transcriptional responses, including innate immunity, and (iii) repress apoptosis. Previous work showed that G3BP1 is phosphorylated at serine 149, which regulates G3BP1 oligomerization, stress granule assembly, and RNase activity intrinsic to G3BP1. However, the kinase that phosphorylates G3BP1 was not identified, leaving a key step in stress granule regulation uncharacterized. Here, using chemical inhibition, genetic depletion, and overexpression experiments, we show that casein kinase 2 (CK2) promotes stress granule dynamics. These results link CK2 activity with SG disassembly. We also show that casein kinase 2 phosphorylates G3BP1 at serine 149 in vitro and in cells. These data support a role for casein kinase 2 in regulation of protein synthesis by downregulating stress granule formation through G3BP1.
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26
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Dou N, Chen J, Yu S, Gao Y, Li Y. G3BP1 contributes to tumor metastasis via upregulation of Slug expression in hepatocellular carcinoma. Am J Cancer Res 2016; 6:2641-2650. [PMID: 27904777 PMCID: PMC5126279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 06/06/2023] Open
Abstract
RasGAP SH3-domain-Binding Protein 1 (G3BP1) has been implicated in cell growth, migration, and metastasis of some cancers, yet its function in hepatocellular carcinoma (HCC) remains to be explored. In the present study, we reported that G3BP1 was upregulated in HCC tissues compared with adjacent non-cancerous liver tissues both in mRNA and protein levels, and its high expression was significantly correlated with poor prognosis of HCC patients. Functional analyses demonstrated that forced expression of G3BP1 in HCC cells promoted cell migration, and silenced expression of G3BP1 by RNA interference caused opposite effects. Moreover, G3BP1 knockdown attenuated the distant metastasis capacity of HCC cells through tail vein injection approach in nude mice model. At molecular mechanism, we found G3BP1 knockdown decreased Slug expression, and increased the expression of the epithelial cell marker E-cadherin. Overexpression of Slug could restore the phenotype of G3BP1 silencing induced cell migration inhibition. Together, our data establish G3BP1 as an oncogenic factor involved in the metastasis of HCC and suggest that G3BP1 might serve as a novel predictor for patients' outcome.
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Affiliation(s)
- Ning Dou
- Department of Oncology, Shanghai East Hospital, Tongji University School of MedicineShanghai 200120, China
| | - Jingde Chen
- Department of Oncology, Shanghai East Hospital, Tongji University School of MedicineShanghai 200120, China
| | - Shijun Yu
- Department of Oncology, Shanghai East Hospital, Tongji University School of MedicineShanghai 200120, China
| | - Yong Gao
- Department of Oncology, Shanghai East Hospital, Tongji University School of MedicineShanghai 200120, China
| | - Yandong Li
- Department of Oncology, Shanghai East Hospital, Tongji University School of MedicineShanghai 200120, China
- Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of MedicineShanghai 200120, China
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27
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Martin S, Bellora N, González-Vallinas J, Irimia M, Chebli K, de Toledo M, Raabe M, Eyras E, Urlaub H, Blencowe BJ, Tazi J. Preferential binding of a stable G3BP ribonucleoprotein complex to intron-retaining transcripts in mouse brain and modulation of their expression in the cerebellum. J Neurochem 2016; 139:349-368. [PMID: 27513819 DOI: 10.1111/jnc.13768] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 08/02/2016] [Accepted: 08/02/2016] [Indexed: 12/13/2022]
Abstract
Neuronal granules play an important role in the localization and transport of translationally silenced messenger ribonucleoproteins in neurons. Among the factors associated with these granules, the RNA-binding protein G3BP1 (stress-granules assembly factor) is involved in neuronal plasticity and is induced in Alzheimer's disease. We immunopurified a stable complex containing G3BP1 from mouse brain and performed high-throughput sequencing and cross-linking immunoprecipitation to identify the associated RNAs. The G3BP-complex contained the deubiquitinating protease USP10, CtBP1 and the RNA-binding proteins Caprin-1, G3BP2a and splicing factor proline and glutamine rich, or PSF. The G3BP-complex binds preferentially to transcripts that retain introns, and to non-coding sequences like 3'-untranslated region and long non-coding RNAs. Specific transcripts with retained introns appear to be enriched in the cerebellum compared to the rest of the brain and G3BP1 depletion decreased this intron retention in the cerebellum of G3BP1 knockout mice. Among the enriched transcripts, we found an overrepresentation of genes involved in synaptic transmission, especially glutamate-related neuronal transmission. Notably, G3BP1 seems to repress the expression of the mature Grm5 (metabotropic glutamate receptor 5) transcript, by promoting the retention of an intron in the immature transcript in the cerebellum. Our results suggest that G3BP is involved in a new functional mechanism to regulate non-coding RNAs including intron-retaining transcripts, and thus have broad implications for neuronal gene regulation, where intron retention is widespread.
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Affiliation(s)
- Sophie Martin
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR5535, Montpellier, France
| | - Nicolas Bellora
- Computational Genomics Group Universitat Pompeu Fabra PRBB, Barcelona, Spain.,Laboratorio de Microbiología Aplicada y Biotecnología, Instituto Andino-Patagónico de Tecnologías Biológicas y Geoambientales (IPATEC), CONICET - UNComahue, Bariloche, Argentina
| | | | - Manuel Irimia
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Karim Chebli
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR5535, Montpellier, France
| | - Marion de Toledo
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR5535, Montpellier, France
| | - Monika Raabe
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Eduardo Eyras
- Computational Genomics Group Universitat Pompeu Fabra PRBB, Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, Barcelona, Spain
| | - Henning Urlaub
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ben J Blencowe
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Jamal Tazi
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR5535, Montpellier, France.
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28
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Heulot M, Chevalier N, Puyal J, Margue C, Michel S, Kreis S, Kulms D, Barras D, Nahimana A, Widmann C. The TAT-RasGAP317-326 anti-cancer peptide can kill in a caspase-, apoptosis-, and necroptosis-independent manner. Oncotarget 2016; 7:64342-64359. [PMID: 27602963 PMCID: PMC5325447 DOI: 10.18632/oncotarget.11841] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 08/24/2016] [Indexed: 01/07/2023] Open
Abstract
Tumor cell resistance to apoptosis, which is triggered by many anti-tumor therapies, remains a major clinical problem. Therefore, development of more efficient therapies is a priority to improve cancer prognosis. We have previously shown that a cell-permeable peptide derived from the p120 Ras GTPase-activating protein (RasGAP), called TAT-RasGAP317-326, bears anti-malignant activities in vitro and in vivo, such as inhibition of metastatic progression and tumor cell sensitization to cell death induced by various anti-cancer treatments. Recently, we discovered that this RasGAP-derived peptide possesses the ability to directly kill some cancer cells. TAT-RasGAP317-326 can cause cell death in a manner that can be either partially caspase-dependent or fully caspase-independent. Indeed, TAT-RasGAP317-326-induced toxicity was not or only partially prevented when apoptosis was inhibited. Moreover, blocking other forms of cell death, such as necroptosis, parthanatos, pyroptosis and autophagy did not hamper the killing activity of the peptide. The death induced by TAT-RasGAP317-326 can therefore proceed independently from these modes of death. Our finding has potentially interesting clinical relevance because activation of a death pathway that is distinct from apoptosis and necroptosis in tumor cells could lead to the generation of anti-cancer drugs that target pathways not yet considered for cancer treatment.
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Affiliation(s)
- Mathieu Heulot
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Nadja Chevalier
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Julien Puyal
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Christiane Margue
- Signal Transduction Laboratory, Life Sciences Research Unit, University of Luxembourg, Luxembourg, Luxembourg
| | - Sébastien Michel
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Stephanie Kreis
- Signal Transduction Laboratory, Life Sciences Research Unit, University of Luxembourg, Luxembourg, Luxembourg
| | - Dagmar Kulms
- Experimental Dermatology, Department of Dermatology, TU-Dresden, Dresden, Germany
- Center for Regenerative Therapies, TU-Dresden, Dresden, Germany
| | - David Barras
- Bioinformatics Core Facility, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Aimable Nahimana
- Service and Central Laboratory of Hematology, University Hospital of Lausanne, Lausanne, Switzerland
| | - Christian Widmann
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
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29
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Kristensen O. Crystal structure of the G3BP2 NTF2-like domain in complex with a canonical FGDF motif peptide. Biochem Biophys Res Commun 2015; 467:53-7. [PMID: 26410532 DOI: 10.1016/j.bbrc.2015.09.123] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 09/22/2015] [Indexed: 01/09/2023]
Abstract
The crystal structure of the NTF2-like domain of the human Ras GTPase SH3 Binding Protein (G3BP), isoform 2, was determined at a resolution of 2.75 Å in complex with a peptide containing a FGDF sequence motif. The overall structure of the protein is highly similar to the homodimeric N-terminal domains of the G3BP1 and Rasputin proteins. Recently, a subset of G3BP interacting proteins was recognized to share a common sequence motif, FGDF. The most studied binding partners, USP10 and viral nsP3, interfere with essential G3BP functions related to assembly of cellular stress granules. Reported molecular modeling suggested that FGDF-motif containing peptides bind in an extended conformation into a hydrophobic groove on the surface of the G3BP NTF2-like domain in a manner similar to the known binding of FxFG nucleoporin repeats. The results in this paper provide evidence for a different binding mode. The FGDF peptide binds and changes conformation of the protruding N-terminal residues by providing hydrophobic interactions to a symmetry related molecule that facilitated crystallization of the G3BP2 isoform.
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Affiliation(s)
- Ole Kristensen
- Biostructural Research, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
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30
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Cailliau K, Lescuyer A, Burnol AF, Cuesta-Marbán Á, Widmann C, Browaeys-Poly E. RasGAP Shields Akt from Deactivating Phosphatases in Fibroblast Growth Factor Signaling but Loses This Ability Once Cleaved by Caspase-3. J Biol Chem 2015; 290:19653-65. [PMID: 26109071 DOI: 10.1074/jbc.m115.644633] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Indexed: 11/06/2022] Open
Abstract
Fibroblast growth factor receptors (FGFRs) are involved in proliferative and differentiation physiological responses. Deregulation of FGFR-mediated signaling involving the Ras/PI3K/Akt and the Ras/Raf/ERK MAPK pathways is causally involved in the development of several cancers. The caspase-3/p120 RasGAP module is a stress sensor switch. Under mild stress conditions, RasGAP is cleaved by caspase-3 at position 455. The resulting N-terminal fragment, called fragment N, stimulates anti-death signaling. When caspase-3 activity further increases, fragment N is cleaved at position 157. This generates a fragment, called N2, that no longer protects cells. Here, we investigated in Xenopus oocytes the impact of RasGAP and its fragments on FGF1-mediated signaling during G2/M cell cycle transition. RasGAP used its N-terminal Src homology 2 domain to bind FGFR once stimulated by FGF1, and this was necessary for the recruitment of Akt to the FGFR complex. Fragment N, which did not associate with the FGFR complex, favored FGF1-induced ERK stimulation, leading to accelerated G2/M transition. In contrast, fragment N2 bound the FGFR, and this inhibited mTORC2-dependent Akt Ser-473 phosphorylation and ERK2 phosphorylation but not phosphorylation of Akt on Thr-308. This also blocked cell cycle progression. Inhibition of Akt Ser-473 phosphorylation and entry into G2/M was relieved by PHLPP phosphatase inhibition. Hence, full-length RasGAP favors Akt activity by shielding it from deactivating phosphatases. This shielding was abrogated by fragment N2. These results highlight the role played by RasGAP in FGFR signaling and how graded stress intensities, by generating different RasGAP fragments, can positively or negatively impact this signaling.
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Affiliation(s)
- Katia Cailliau
- From the Université de Lille 1, Sciences et Technologies, Team Signal Division Regulation, CNRS UMR 8576, SN3, 59655 Villeneuve d'Ascq Cedex, France,
| | - Arlette Lescuyer
- From the Université de Lille 1, Sciences et Technologies, Team Signal Division Regulation, CNRS UMR 8576, SN3, 59655 Villeneuve d'Ascq Cedex, France
| | - Anne-Françoise Burnol
- INSERM, U1016, Institut Cochin, Paris, France, CNRS UMR8104, Institut Cochin, 22 rue Méchain, 75014 Paris, France, the Université Paris Descartes, Sorbonne Paris Cité, 24 Rue du Faubourg Saint Jacques, 75014 Paris, France, and
| | - Álvaro Cuesta-Marbán
- the Department of Physiology, Université de Lausanne, Rue du Bugnon 7, 1005 Lausanne, Switzerland
| | - Christian Widmann
- the Department of Physiology, Université de Lausanne, Rue du Bugnon 7, 1005 Lausanne, Switzerland
| | - Edith Browaeys-Poly
- From the Université de Lille 1, Sciences et Technologies, Team Signal Division Regulation, CNRS UMR 8576, SN3, 59655 Villeneuve d'Ascq Cedex, France
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31
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Min L, Ruan Y, Shen Z, Jia D, Wang X, Zhao J, Sun Y, Gu J. Overexpression of Ras-GTPase-activating protein SH3 domain-binding protein 1 correlates with poor prognosis in gastric cancer patients. Histopathology 2015; 67:677-88. [PMID: 25809930 DOI: 10.1111/his.12695] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 03/16/2015] [Indexed: 01/28/2023]
Abstract
AIMS Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is a downstream effector of Ras signalling, and is overexpressed in several types of human malignancy. However, its role in gastric cancer remains unclear. The aim of this study was to investigate the prognostic significance of G3BP1 in gastric cancer. METHODS AND RESULTS G3BP1 mRNA and protein levels in paired frozen tumour samples were detected by real-time polymerase chain reaction and western blotting, respectively. Paraffin-embedded tumour samples were used for immunohistochemistry. Gastric cancer cells were used to detect the tumorigenic role of G3BP1 in vitro. We found that G3BP1 protein expression was markedly increased in gastric cancer tissues as compared with corresponding non-malignant mucosa, whereas corresponding changes in mRNA levels were not observed. G3BP1 staining was positively correlated with tumour size, vascular invasion, T classification, lymph node metastasis, TNM stage, and reduced overall survival. Further analysis identified G3BP1 as an independent prognostic factor for poor prognosis, and combining G3BP1 with TNM stage generated a better predictive model for patient outcomes. G3BP1 also promoted proliferation, migration/invasion and extracellular signal-related kinase and AKT activation in gastric cancer cells. CONCLUSIONS Our data define G3BP1 as a novel independent prognostic factor that is correlated with gastric cancer progression.
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Affiliation(s)
- Lingqiang Min
- Department of General Surgery, Zhongshan Hospital, Shanghai, China
| | - Yuanyuan Ruan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Zhenbin Shen
- Department of General Surgery, Zhongshan Hospital, Shanghai, China
| | - Dongwei Jia
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Xuefei Wang
- Department of General Surgery, Zhongshan Hospital, Shanghai, China
| | - Junjie Zhao
- Department of General Surgery, Zhongshan Hospital, Shanghai, China
| | - Yihong Sun
- Department of General Surgery, Zhongshan Hospital, Shanghai, China
| | - Jianxin Gu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China
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32
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Oi N, Yuan J, Malakhova M, Luo K, Li Y, Ryu J, Zhang L, Bode AM, Xu Z, Li Y, Lou Z, Dong Z. Resveratrol induces apoptosis by directly targeting Ras-GTPase-activating protein SH3 domain-binding protein 1. Oncogene 2015; 34:2660-71. [PMID: 24998844 PMCID: PMC4286533 DOI: 10.1038/onc.2014.194] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 05/06/2014] [Accepted: 05/09/2014] [Indexed: 12/12/2022]
Abstract
Resveratrol (trans-3,5,4'-truhydroxystilbene) possesses a strong anticancer activity exhibited as the induction of apoptosis through p53 activation. However, the molecular mechanism and direct target(s) of resveratrol-induced p53 activation remain elusive. Here, the Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) was identified as a potential target of resveratrol, and in vitro binding assay results using resveratrol-conjugated Sepharose 4B beads confirmed their direct binding. Depletion of G3BP1 significantly diminishes resveratrol-induced p53 expression and apoptosis. We also found that G3BP1 negatively regulates p53 expression by interacting with ubiquitin-specific protease 10 (USP10), a deubiquitinating enzyme of p53. Disruption of the interaction of p53 with USP10 by G3BP1 interference leads to the suppression of p53 deubiquitination. Resveratrol, on the other hand, directly binds to G3BP1 and prevents the G3BP1/USP10 interaction, resulting in enhanced USP10-mediated deubiquitination of p53, and consequently increased p53 expression. These findings disclose a novel mechanism of resveratrol-induced p53 activation and resveratrol-induced apoptosis by direct targeting of G3BP1.
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Affiliation(s)
- Naomi Oi
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Jian Yuan
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
| | - Margarita Malakhova
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Kuntian Luo
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Division of Oncology Research, Department of Oncology, Mayo Clinic, 200 1st St. SW, Rochester, MN 55905, USA
| | - Yunhui Li
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Division of Oncology Research, Department of Oncology, Mayo Clinic, 200 1st St. SW, Rochester, MN 55905, USA
| | - Joohyun Ryu
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Lei Zhang
- Division of Oncology Research, Department of Oncology, Mayo Clinic, 200 1st St. SW, Rochester, MN 55905, USA
| | - Ann M. Bode
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Zengguang Xu
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Shanghai 200120, China
| | - Yan Li
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
| | - Zhenkun Lou
- Division of Oncology Research, Department of Oncology, Mayo Clinic, 200 1st St. SW, Rochester, MN 55905, USA
| | - Zigang Dong
- The Hormel Institute, University of Minnesota, 801 16th Ave. NE, Austin, MN 55912, USA
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33
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Annibaldi A, Heulot M, Martinou JC, Widmann C. TAT-RasGAP317-326-mediated tumor cell death sensitization can occur independently of Bax and Bak. Apoptosis 2015; 19:719-33. [PMID: 24362790 DOI: 10.1007/s10495-013-0958-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The increase of cancer specificity and efficacy of anti-tumoral agents are prime strategies to overcome the deleterious side effects associated with anti-cancer treatments. We described earlier a cell-permeable protease-resistant peptide derived from the p120 RasGAP protein, called TAT-RasGAP317-326, as being an efficient tumor-specific sensitizer to apoptosis induced by genotoxins in vitro and in vivo. Bcl-2 family members regulate the intrinsic apoptotic response and as such could be targeted by TAT-RasGAP317-326. Our results indicate that the RasGAP-derived peptide increases cisplatin-induced Bax activation. We found no evidence, using in particular knock-out cells, of an involvement of other Bcl-2 family proteins in the tumor-specific sensitization activity of TAT-RasGAP317-326. The absence of Bax and Bak in mouse embryonic fibroblasts rendered them resistant to cisplatin-induced apoptosis and consequently to the sensitizing action of the RasGAP-derived peptide. Surprisingly, in the HCT116 colon carcinoma cell line, the absence of Bax and Bak did not prevent cisplatin-induced apoptosis and the ability of TAT-RasGAP317-326 to augment this response. Our study also revealed that p53, while required for an efficient genotoxin-induced apoptotic response, is dispensable for the ability of the RasGAP-derived peptide to improve the capacity of genotoxins to decrease long-term survival of cancer cells. Hence, even though genotoxin-induced Bax activity can be increased by TAT-RasGAP317-326, the sensitizing activity of the RasGAP-derived peptide can operate in the absence of a functional mitochondrial intrinsic death pathway.
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Affiliation(s)
- Alessandro Annibaldi
- Department of Physiology, University of Lausanne, Rue du Bugnon 7, 1005, Lausanne, Switzerland
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34
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Khalil H, Loukili N, Regamey A, Cuesta-Marban A, Santori E, Huber M, Widmann C. The caspase-3/p120 RasGAP module generates a NF-κB repressor in response to cellular stress. J Cell Sci 2015. [DOI: 10.1242/jcs.174409] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The NF-κB transcription factor is a master regulator of inflammation. Short-term NF-κB activation is generally beneficial. However, sustained NF-κB may be detrimental, directly causing apoptosis of cells or leading to a persistent damaging inflammatory response. NF-κB activity in stressed cells needs therefore to be controlled for homeostasis maintenance. Here we show that fragment N that is produced by the caspase-3/p120 RasGAP sensor in mildly stressed cells is a potent NF-κB inhibitor. Fragment N decreases the transcriptional activity of NF-κB by promoting its export from the nucleus. Cells unable to generate fragment N displayed increased NF-κB activation upon stress. Knock-in mice expressing the uncleavable RasGAP mutant showed exaggerated NF-κB activation when their epidermis was treated with anthralin, a drug used for the treatment of psoriasis. Our study provides biochemical and genetic evidence of the importance of the caspase-3/p120 RasGAP stress-sensing module in the control of stress-induced NF-κB activation.
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Affiliation(s)
- Hadi Khalil
- Department of Physiology, Biology and Medicine Faculty, University of Lausanne, Switzerland
| | - Noureddine Loukili
- Department of Physiology, Biology and Medicine Faculty, University of Lausanne, Switzerland
| | - Alexandre Regamey
- Department of Dermatology, Lausanne University Hospital, Lausanne, Switzerland
| | - Alvaro Cuesta-Marban
- Department of Physiology, Biology and Medicine Faculty, University of Lausanne, Switzerland
| | - Elettra Santori
- Department of Physiology, Biology and Medicine Faculty, University of Lausanne, Switzerland
| | - Marcel Huber
- Department of Dermatology, Lausanne University Hospital, Lausanne, Switzerland
| | - Christian Widmann
- Department of Physiology, Biology and Medicine Faculty, University of Lausanne, Switzerland
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35
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Zhao X, Kang L, Zhang T, Chen J, Ren X, Bao Y, Cheng Y. Rapid quantification of a chemically synthesized peptide GAP162 in rat plasma by liquid chromatography/triple quadrupole tandem mass spectrometry and application to a pharmacokinetic study. RSC Adv 2015. [DOI: 10.1039/c5ra05188f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Liquid chromatography/tandem mass spectrometry (LC-MS/MS) is a promising analytical platform for the quantification of therapeutic peptide in biological fluids for pharmacokinetics (PK) studies.
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Affiliation(s)
- Xiaoping Zhao
- State Key Laboratory of Pathogen and Biosecurity
- Beijing Institute of Microbiology and Epidemiology
- Beijing
- China
| | - Liping Kang
- State Key Laboratory Breeding Base of Dao-di Herbs
- National Resource Center of Chinese Materia Medica
- China Academy of Chinese Medical Sciences
- Beijing
- China
| | | | | | - Xinyi Ren
- State Key Laboratory of Pathogen and Biosecurity
- Beijing Institute of Microbiology and Epidemiology
- Beijing
- China
| | - Yuanwu Bao
- DMPK Department
- BioDuro (Shanghai) Inc
- Shanghai
- China
| | - Yuanguo Cheng
- State Key Laboratory of Pathogen and Biosecurity
- Beijing Institute of Microbiology and Epidemiology
- Beijing
- China
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36
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Vanli G, Peltzer N, Dubuis G, Widmann C. The activity of the anti-apoptotic fragment generated by the caspase-3/p120 RasGAP stress-sensing module displays strict Akt isoform specificity. Cell Signal 2014; 26:2992-7. [PMID: 25246356 DOI: 10.1016/j.cellsig.2014.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/22/2014] [Accepted: 09/15/2014] [Indexed: 02/06/2023]
Abstract
The caspase-3/p120 RasGAP module acts as a stress sensor that promotes pro-survival or pro-death signaling depending on the intensity and the duration of the stressful stimuli. Partial cleavage of p120 RasGAP generates a fragment, called fragment N, which protects stressed cells by activating Akt signaling. Akt family members regulate many cellular processes including proliferation, inhibition of apoptosis and metabolism. These cellular processes are regulated by three distinct Akt isoforms: Akt1, Akt2 and Akt3. However, which of these isoforms are required for fragment N mediated protection have not been defined. In this study, we investigated the individual contribution of each isoform in fragment N-mediated cell protection against Fas ligand induced cell death. To this end, DLD1 and HCT116 isogenic cell lines lacking specific Akt isoforms were used. It was found that fragment N could activate Akt1 and Akt2 but that only the former could mediate the protective activity of the RasGAP-derived fragment. Even overexpression of Akt2 or Akt3 could not rescue the inability of fragment N to protect cells lacking Akt1. These results demonstrate a strict Akt isoform requirement for the anti-apoptotic activity of fragment N.
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Affiliation(s)
- Güliz Vanli
- Department of Physiology, University of Lausanne, Switzerland
| | - Nieves Peltzer
- Department of Physiology, University of Lausanne, Switzerland
| | - Gilles Dubuis
- Department of Physiology, University of Lausanne, Switzerland
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37
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Martin S, Tazi J. Visualization of G3BP stress granules dynamics in live primary cells. J Vis Exp 2014. [PMID: 24893963 DOI: 10.3791/51197] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
SGs can be visualized in cells by immunostaining of specific protein components or polyA+ mRNAs. SGs are highly dynamic and the study of their assembly and fate is important to understand the cellular response to stress. The deficiency in key factors of SGs like G3BP (RasGAP SH3 domain Binding Protein) leads to developmental defects in mice and alterations of the Central Nervous System. To study the dynamics of SGs in cells from an organism, one can culture primary cells and follow the localization of a transfected tagged component of SGs. We describe time-lapse experiment to observe G3BP1-containing SGs in Mouse Embryonic Fibroblasts (MEFs). This technique can also be used to study G3BP-containing SGs in live neurons, which is crucial as it was recently shown that these SGs are formed at the onset of neurodegenerative diseases like Alzheimer's disease. This approach can be adapted to any other cellular body and granule protein component, and performed with transgenic animals, allowing the live study of granules dynamics for example in the absence of a specific factor of these granules.
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Affiliation(s)
- Sophie Martin
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR 5535;
| | - Jamal Tazi
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR 5535
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38
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Winslow S, Leandersson K, Larsson C. Regulation of PMP22 mRNA by G3BP1 affects cell proliferation in breast cancer cells. Mol Cancer 2013; 12:156. [PMID: 24321297 PMCID: PMC3866477 DOI: 10.1186/1476-4598-12-156] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 11/27/2013] [Indexed: 12/21/2022] Open
Abstract
Background Regulation of mRNAs is one way to control protein levels and thereby important cellular processes such as growth, invasion and apoptosis. G3BPs constitute a family of mRNA-binding proteins, shown to be overexpressed in several cancer types, including breast, colon and pancreas cancer. G3BP has been reported to both stabilize and induce degradation of specific mRNAs. Results Here, we show that G3BP1, but not G3BP2, supports proliferation of several breast cancer cell lines. Global gene expression analyses of G3BP1- and G3BP2-depleted cells indicate that primarily G3BP1, and much less G3BP2, influences mRNA expression levels. Peripheral myelin protein 22 (PMP22) was one gene that was significantly influenced by G3BP1 depletion which led to a 2–3 fold increased expression. Depletion of PMP22 resulted in increased proliferation and the G3BP1-mediated effect on proliferation was not seen upon PMP22-depletion. Conclusions This indicates a novel role for G3BP1 in the regulation of cell proliferation in breast cancer cells, perhaps via a regulatory effect on PMP22 expression.
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Affiliation(s)
| | | | - Christer Larsson
- Department of Laboratory Medicine, Translational Cancer Research, Lund University, Medicon Village, Building 404:C3, Lund, 223 81, Sweden.
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39
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Crystal structures of the human G3BP1 NTF2-like domain visualize FxFG Nup repeat specificity. PLoS One 2013; 8:e80947. [PMID: 24324649 PMCID: PMC3852005 DOI: 10.1371/journal.pone.0080947] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 10/08/2013] [Indexed: 11/19/2022] Open
Abstract
Ras GTPase Activating Protein SH3 Domain Binding Protein (G3BP) is a potential anti-cancer drug target implicated in several cellular functions. We have used protein crystallography to solve crystal structures of the human G3BP1 NTF2-like domain both alone and in complex with an FxFG Nup repeat peptide. Despite high structural similarity, the FxFG binding site is located between two alpha helices in the G3BP1 NTF2-like domain and not at the dimer interface as observed for nuclear transport factor 2. ITC studies showed specificity towards the FxFG motif but not FG and GLFG motifs. The unliganded form of the G3BP1 NTF2-like domain was solved in two crystal forms to resolutions of 1.6 and 3.3 Å in space groups P212121 and P6322 based on two different constructs, residues 1–139 and 11–139, respectively. Crystal packing of the N-terminal residues against a symmetry related molecule in the P212121 crystal form might indicate a novel ligand binding site that, however, remains to be validated. The crystal structures give insight into the nuclear transportation mechanisms of G3BP and provide a basis for future structure based drug design.
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40
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Peltzer N, Vanli G, Yang JY, Widmann C. Role of mTOR, Bad, and Survivin in RasGAP Fragment N-Mediated Cell Protection. PLoS One 2013; 8:e68123. [PMID: 23826368 PMCID: PMC3694949 DOI: 10.1371/journal.pone.0068123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 05/30/2013] [Indexed: 01/04/2023] Open
Abstract
Partial cleavage of p120 RasGAP by caspase-3 in stressed cells generates an N-terminal fragment, called fragment N, which activates an anti-apoptotic Akt-dependent survival response. Akt regulates several effectors but which of these mediate fragment N-dependent cell protection has not been defined yet. Here we have investigated the role of mTORC1, Bad, and survivin in the capacity of fragment N to protect cells from apoptosis. Neither rapamycin, an inhibitor of mTORC1, nor silencing of raptor, a subunit of the mTORC1 complex, altered the ability of fragment N from inhibiting cisplatin- and Fas ligand-induced death. Cells lacking Bad, despite displaying a stronger resistance to apoptosis, were still protected by fragment N against cisplatin-induced death. Fragment N was also able to protect cells from Fas ligand-induced death in conditions where Bad plays no role in apoptosis regulation. Fragment N expression in cells did neither modulate survivin mRNA nor its protein expression. Moreover, the expression of cytoplasmic survivin, known to exert anti-apoptotic actions in cells, still occurred in UV-B-irradiated epidermis of mouse expressing a caspase-3-resistant RasGAP mutant that cannot produce fragment N. Additionally, survivin function in cell cycle progression was not affected by fragment N. These results indicate that, taken individually, mTOR, Bad, or Survivin are not required for fragment N to protect cells from cell death. We conclude that downstream targets of Akt other than mTORC1, Bad, or survivin mediate fragment N-induced protection or that several Akt effectors can compensate for each other to induce the pro-survival fragment N-dependent response.
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Affiliation(s)
- Nieves Peltzer
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Güliz Vanli
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Jiang-Yan Yang
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Christian Widmann
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
- * E-mail:
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41
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Xu C, Wang P, Liu Y, Zhang Y, Fan W, Upton MP, Lohavanichbutr P, Houck JR, Doody DR, Futran ND, Zhao LP, Schwartz SM, Chen C, Méndez E. Integrative genomics in combination with RNA interference identifies prognostic and functionally relevant gene targets for oral squamous cell carcinoma. PLoS Genet 2013; 9:e1003169. [PMID: 23341773 PMCID: PMC3547824 DOI: 10.1371/journal.pgen.1003169] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 10/29/2012] [Indexed: 12/22/2022] Open
Abstract
In oral squamous cell carcinoma (OSCC), metastasis to lymph nodes is associated with a 50% reduction in 5-year survival. To identify a metastatic gene set based on DNA copy number abnormalities (CNAs) of differentially expressed genes, we compared DNA and RNA of OSCC cells laser-microdissected from non-metastatic primary tumors (n = 17) with those from lymph node metastases (n = 20), using Affymetrix 250K Nsp single-nucleotide polymorphism (SNP) arrays and U133 Plus 2.0 arrays, respectively. With a false discovery rate (FDR)<5%, 1988 transcripts were found to be differentially expressed between primary and metastatic OSCC. Of these, 114 were found to have a significant correlation between DNA copy number and gene expression (FDR<0.01). Among these 114 correlated transcripts, the corresponding genomic regions of each of 95 transcripts had CNAs differences between primary and metastatic OSCC (FDR<0.01). Using an independent dataset of 133 patients, multivariable analysis showed that the OSCC–specific and overall mortality hazards ratio (HR) for patients carrying the 95-transcript signature were 4.75 (95% CI: 2.03–11.11) and 3.45 (95% CI: 1.84–6.50), respectively. To determine the degree by which these genes impact cell survival, we compared the growth of five OSCC cell lines before and after knockdown of over-amplified transcripts via a high-throughput siRNA–mediated screen. The expression-knockdown of 18 of the 26 genes tested showed a growth suppression ≥30% in at least one cell line (P<0.01). In particular, cell lines derived from late-stage OSCC were more sensitive to the knockdown of G3BP1 than cell lines derived from early-stage OSCC, and the growth suppression was likely caused by increase in apoptosis. Further investigation is warranted to examine the biological role of these genes in OSCC progression and their therapeutic potentials. Neck lymph node metastasis is the most important prognostic factor in oral squamous cell carcinoma (OSCC). To identify genes associated with this critical step of OSCC progression, we compared DNA copy number aberrations and gene expression differences between tumor cells found in metastatic lymph nodes versus those in non-metastatic primary tumors. We identified 95 transcripts (87 genes) with metastasis-specific genome abnormalities and gene expression. Tested in an independent cohort of 133 OSCC patients, the 95 gene signature was an independent risk factor of disease-specific and overall death, suggesting a disease progression phenotype. We knocked down the expression of over-amplified genes in five OSCC cell lines. Knockdown of 18 of the 26 tested genes suppressed the cell growth in at least one cell line. Interestingly, cell lines derived from late-stage OSCC were more sensitive to the knockdown of G3BP1 than cell lines derived from early-stage OSCC. The knockdown of G3BP1 increased programmed cell death in the p53-mutant but not wild-type OSCC cell lines. Taken together, we demonstrate that CNA–associated transcripts differentially expressed in carcinoma cells with an aggressive phenotype (i.e., metastatic to lymph nodes) can be biomarkers with both prognostic information and functional relevance. Moreover, results suggest that G3BP1 is a potential therapeutic target against late-stage p53-negative OSCC.
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Affiliation(s)
- Chang Xu
- Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle, Washington, United States of America
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Pei Wang
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Yan Liu
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Yuzheng Zhang
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Wenhong Fan
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Melissa P. Upton
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - Pawadee Lohavanichbutr
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - John R. Houck
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - David R. Doody
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Neal D. Futran
- Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle, Washington, United States of America
| | - Lue Ping Zhao
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Stephen M. Schwartz
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - Chu Chen
- Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle, Washington, United States of America
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - Eduardo Méndez
- Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle, Washington, United States of America
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Surgery and Perioperative Care Service, VA Puget Sound Health Care System, Seattle, Washington, United States of America
- * E-mail:
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42
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Khalil H, Rosenblatt N, Liaudet L, Widmann C. The role of endogenous and exogenous RasGAP-derived fragment N in protecting cardiomyocytes from peroxynitrite-induced apoptosis. Free Radic Biol Med 2012; 53:926-35. [PMID: 22721922 DOI: 10.1016/j.freeradbiomed.2012.06.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 05/18/2012] [Accepted: 06/07/2012] [Indexed: 11/15/2022]
Abstract
Peroxynitrite (PN) is a potent nitrating and oxidizing agent generated during various pathological situations affecting the heart. The negative effects of PN result, at least in part, from its ability to activate caspases and apoptosis. RasGAP is a ubiquitously expressed protein that is cleaved sequentially by caspase-3. At low caspase-3 activity, RasGAP is cleaved into an N-terminal fragment, called fragment N, that protects cells by activating the Ras/PI3K/Akt pathway. At high caspase-3 activity, fragment N is further cleaved and this abrogates its capacity to stimulate the antiapoptotic Akt kinase. Fragment N formation is crucial for the survival of cells exposed to a variety of stresses. Here we investigate the pattern of RasGAP cleavage upon PN stimulation and the capacity of fragment N to protect cardiomyocytes. PN did not lead to sequential cleavage of RasGAP. Indeed, PN did not allow accumulation of fragment N because it induced its rapid cleavage into smaller fragments. No situations were found in cells treated with PN in which the presence of fragment N was associated with survival. However, expression of a caspase-resistant form of fragment N in cardiomyocytes protected them from PN-induced apoptosis. Our results indicate that the antiapoptotic pathway activated by fragment N is effective at inhibiting PN-induced apoptosis (as seen when cardiomyocytes express a capase-3-resistant form of fragment N) but because fragment N is too transiently generated in response to PN, no survival response is effectively produced. This may explain the marked deleterious consequences of PN generation in various organs, including the heart.
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Affiliation(s)
- Hadi Khalil
- Department of Physiology, Biology and Medicine Faculty, University of Lausanne, 1005 Lausanne, Switzerland
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Crystal structure of the Rasputin NTF2-like domain from Drosophila melanogaster. Biochem Biophys Res Commun 2012; 420:188-92. [PMID: 22414690 DOI: 10.1016/j.bbrc.2012.02.140] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 02/27/2012] [Indexed: 11/22/2022]
Abstract
The crystal structure of the NTF2-like domain of the Drosophila homolog of Ras GTPase SH3 Binding Protein (G3BP), Rasputin, was determined at 2.7Å resolution. The overall structure is highly similar to nuclear transport factor 2: It is a homodimer comprised of a β-sheet and three α-helices forming a cone-like shape. However, known binding sites for RanGDP and FxFG containing peptides show electrostatic and steric differences compared to nuclear transport factor 2. A HEPES molecule bound in the structure suggests a new, and possibly physiologically relevant, ligand binding site.
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