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Ma X, Li J, Liu N, Banerjee S, Hu X, Wang X, Dong J, Liu K, Yang C, Dong Z. Insights into the distinct membrane targeting mechanisms of WDR91 family proteins. Structure 2024:S0969-2126(24)00423-4. [PMID: 39426373 DOI: 10.1016/j.str.2024.09.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 07/15/2024] [Accepted: 09/24/2024] [Indexed: 10/21/2024]
Abstract
WDR91 and SORF1, members of the WD repeat-containing protein 91 family, control phosphoinositide conversion by inhibiting phosphatidylinositol 3-kinase activity on endosomes, which promotes endosome maturation. Here, we report the crystal structure of the human WDR91 WD40 domain complexed with Rab7 that has an unusual interface at the C-terminus of the Rab7 switch II region. WDR91 is highly selective for Rab7 among the tested GTPases. A LIS1 homology (LisH) motif within the WDR91 N-terminal domain (NTD) mediates self-association and may contribute partly to the augmented interaction between full-length WDR91 and Rab7. Both the Rab7 binding site and the LisH motif are indispensable for WDR91 function in endocytic trafficking. For the WDR91 orthologue SORF1 lacking the C-terminal WD40 domain, a C-terminal amphipathic helix (AH) mediates strong interactions with liposomes containing acidic lipids. During evolution the human WDR91 ancestor gene might have acquired a WD40 domain to replace the AH for endosomal membrane targeting.
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Affiliation(s)
- Xinli Ma
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, Henan 450003, China
| | - Jian Li
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, Henan 450003, China
| | - Nan Liu
- State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan and Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Surajit Banerjee
- Northeastern Collaborative Access Team, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Xiaotong Hu
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, Henan 450003, China
| | - Xiaoyu Wang
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, Henan 450003, China
| | - Jianshu Dong
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Kangdong Liu
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, Henan 450003, China; College of Medicine, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Chonglin Yang
- State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan and Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Zigang Dong
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, Henan 450003, China; College of Medicine, Zhengzhou University, Zhengzhou, Henan 450052, China.
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2
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Zhang Y, Chen Y, Mou H, Huang Q, Jian C, Tao Y, Tan F, Ou Y. Synergistic induction of ferroptosis by targeting HERC1-NCOA4 axis to enhance the photodynamic sensitivity of osteosarcoma. Redox Biol 2024; 76:103328. [PMID: 39216271 PMCID: PMC11402416 DOI: 10.1016/j.redox.2024.103328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 08/16/2024] [Accepted: 08/24/2024] [Indexed: 09/04/2024] Open
Abstract
Over the past 30 years, the survival rate for osteosarcoma (OS) has remained stagnant, indicating persistent challenges in diagnosis and treatment. Photodynamic therapy (PDT) has emerged as a novel and promising treatment modality for OS. Despite apoptosis being the primary mechanism attributed to PDT, it fails to overcome issues such as low efficacy and resistance. Ferroptosis, a Fe2+-dependent cell death process, has the potential to enhance PDT's efficacy by increasing reactive oxygen species (ROS) through the Fenton reaction. In this study, we investigated the anti-tumor mechanism of PDT and introduced an innovative therapeutic strategy that synergistically induces apoptosis and ferroptosis. Furthermore, we have identified HERC1 as a pivotal protein involved in the ubiquitination and degradation of NCOA4, while also uncovering a potential regulatory factor involving NRF2. Ultimately, by targeting the HERC1-NCOA4 axis during PDT, we successfully achieved full activation of ferroptosis, which significantly enhanced the anti-tumor efficacy of PDT. In conclusion, these findings provide new theoretical evidence for further characterizing mechanism of PDT and offer new molecular targets for the treatment of OS.
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Affiliation(s)
- Ye Zhang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing, 400016, China; Orthopaedic Research Laboratory of Chongqing Medical University, Yuzhong, Chongqing, 400016, China
| | - Yuxing Chen
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing, 400016, China; Orthopaedic Research Laboratory of Chongqing Medical University, Yuzhong, Chongqing, 400016, China
| | - Hai Mou
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Yuzhong, Chongqing, 400016, China
| | - Qiu Huang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing, 400016, China; Orthopaedic Research Laboratory of Chongqing Medical University, Yuzhong, Chongqing, 400016, China
| | - Changchun Jian
- Department of Orthopaedics, The Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, 637000, China
| | - Yong Tao
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing, 400016, China; Orthopaedic Research Laboratory of Chongqing Medical University, Yuzhong, Chongqing, 400016, China
| | - Fuqiang Tan
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing, 400016, China; Orthopaedic Research Laboratory of Chongqing Medical University, Yuzhong, Chongqing, 400016, China
| | - Yunsheng Ou
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing, 400016, China; Orthopaedic Research Laboratory of Chongqing Medical University, Yuzhong, Chongqing, 400016, China.
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3
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Huang SK, Rubinstein JL, Kay LE. Cryo-EM of the Nucleosome Core Particle Bound to Ran-RCC1 Reveals a Dynamic Complex. Biochemistry 2024; 63:880-892. [PMID: 38501608 DOI: 10.1021/acs.biochem.3c00724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Ras-related nuclear protein (Ran) is a member of the Ras superfamily of small guanosine triphosphatases (GTPases) and a regulator of multiple cellular processes. In healthy cells, the GTP-bound form of Ran is concentrated at chromatin, creating a Ran•GTP gradient that provides the driving force for nucleocytoplasmic transport, mitotic spindle assembly, and nuclear envelope formation. The Ran•GTP gradient is maintained by the regulator of chromatin condensation 1 (RCC1), a guanine nucleotide exchange factor that accelerates GDP/GTP exchange in Ran. RCC1 interacts with nucleosomes, which are the fundamental repeating units of eukaryotic chromatin. Here, we present a cryo-EM analysis of a trimeric complex composed of the nucleosome core particle (NCP), RCC1, and Ran. While the contacts between RCC1 and Ran in the complex are preserved compared with a previously determined structure of RCC1-Ran, our study reveals that RCC1 and Ran interact dynamically with the NCP and undergo rocking motions on the nucleosome surface. Furthermore, the switch 1 region of Ran, which plays an important role in mediating conformational changes associated with the substitution of GDP and GTP nucleotides in Ras family members, appears to undergo disorder-order transitions and forms transient contacts with the C-terminal helix of histone H2B. Nucleotide exchange assays performed in the presence and absence of NCPs are not consistent with an active role for nucleosomes in nucleotide exchange, at least in vitro. Instead, the nucleosome stabilizes RCC1 and serves as a hub that concentrates RCC1 and Ran to promote efficient Ran•GDP to Ran•GTP conversion.
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Affiliation(s)
- Shuya Kate Huang
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Hospital for Sick Children, Program in Molecular Medicine, Toronto, ON M5G 1X8, Canada
| | - John L Rubinstein
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Hospital for Sick Children, Program in Molecular Medicine, Toronto, ON M5G 1X8, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Lewis E Kay
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Hospital for Sick Children, Program in Molecular Medicine, Toronto, ON M5G 1X8, Canada
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4
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Yang Y, Guo L, Chen L, Gong B, Jia D, Sun Q. Nuclear transport proteins: structure, function, and disease relevance. Signal Transduct Target Ther 2023; 8:425. [PMID: 37945593 PMCID: PMC10636164 DOI: 10.1038/s41392-023-01649-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 11/12/2023] Open
Abstract
Proper subcellular localization is crucial for the functioning of biomacromolecules, including proteins and RNAs. Nuclear transport is a fundamental cellular process that regulates the localization of many macromolecules within the nuclear or cytoplasmic compartments. In humans, approximately 60 proteins are involved in nuclear transport, including nucleoporins that form membrane-embedded nuclear pore complexes, karyopherins that transport cargoes through these complexes, and Ran system proteins that ensure directed and rapid transport. Many of these nuclear transport proteins play additional and essential roles in mitosis, biomolecular condensation, and gene transcription. Dysregulation of nuclear transport is linked to major human diseases such as cancer, neurodegenerative diseases, and viral infections. Selinexor (KPT-330), an inhibitor targeting the nuclear export factor XPO1 (also known as CRM1), was approved in 2019 to treat two types of blood cancers, and dozens of clinical trials of are ongoing. This review summarizes approximately three decades of research data in this field but focuses on the structure and function of individual nuclear transport proteins from recent studies, providing a cutting-edge and holistic view on the role of nuclear transport proteins in health and disease. In-depth knowledge of this rapidly evolving field has the potential to bring new insights into fundamental biology, pathogenic mechanisms, and therapeutic approaches.
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Affiliation(s)
- Yang Yang
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Lu Guo
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Lin Chen
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Bo Gong
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China.
| | - Qingxiang Sun
- Department of Pulmonary and Critical Care Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu, China.
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5
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Hodáková Z, Grishkovskaya I, Brunner HL, Bolhuis DL, Belačić K, Schleiffer A, Kotisch H, Brown NG, Haselbach D. Cryo-EM structure of the chain-elongating E3 ubiquitin ligase UBR5. EMBO J 2023; 42:e113348. [PMID: 37409633 PMCID: PMC10425842 DOI: 10.15252/embj.2022113348] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/30/2023] [Accepted: 06/14/2023] [Indexed: 07/07/2023] Open
Abstract
UBR5 is a nuclear E3 ligase that ubiquitinates a vast range of substrates for proteasomal degradation. This HECT domain-containing ubiquitin ligase has recently been identified as an important regulator of oncogenes, e.g., MYC, but little is known about its structure or mechanisms of substrate engagement and ubiquitination. Here, we present the cryo-EM structure of human UBR5, revealing an α-solenoid scaffold with numerous protein-protein interacting motifs, assembled into an antiparallel dimer that adopts further oligomeric states. Using cryo-EM processing tools, we observe the dynamic nature of the UBR5 catalytic domain, which we postulate is important for its enzymatic activity. We characterise the proteasomal nuclear import factor AKIRIN2 as an interacting protein and propose UBR5 as an efficient ubiquitin chain elongator. This preference for ubiquitinated substrates and several distinct domains for protein-protein interactions may explain how UBR5 is linked to several different signalling pathways and cancers. Together, our data expand on the limited knowledge of the structure and function of HECT E3 ligases.
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Affiliation(s)
- Zuzana Hodáková
- Research Institute of Molecular Pathology (IMP), ViennaBioCenter (VBC)ViennaAustria
| | - Irina Grishkovskaya
- Research Institute of Molecular Pathology (IMP), ViennaBioCenter (VBC)ViennaAustria
| | - Hanna L Brunner
- Research Institute of Molecular Pathology (IMP), ViennaBioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD ProgramDoctoral School of the University of Vienna and Medical University of ViennaViennaAustria
| | - Derek L Bolhuis
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer CenterUniversity of North Carolina School of MedicineChapel HillNCUSA
| | - Katarina Belačić
- Research Institute of Molecular Pathology (IMP), ViennaBioCenter (VBC)ViennaAustria
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP), ViennaBioCenter (VBC)ViennaAustria
| | - Harald Kotisch
- Research Institute of Molecular Pathology (IMP), ViennaBioCenter (VBC)ViennaAustria
| | - Nicholas G Brown
- Department of Pharmacology and Lineberger Comprehensive Cancer CenterUniversity of North Carolina School of MedicineChapel HillNCUSA
| | - David Haselbach
- Research Institute of Molecular Pathology (IMP), ViennaBioCenter (VBC)ViennaAustria
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6
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Liu X, Han S, Liu F, Yu S, Qin Y, Li J, Jia D, Gao P, Chen X, Tang Z, Liu M, Huang Y. Retinal degeneration in rpgra mutant zebrafish. Front Cell Dev Biol 2023; 11:1169941. [PMID: 37351277 PMCID: PMC10282147 DOI: 10.3389/fcell.2023.1169941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 05/24/2023] [Indexed: 06/24/2023] Open
Abstract
Introduction: Pathogenic mutations in RPGR ORF15, one of two major human RPGR isoforms, were responsible for most X-linked retinitis pigmentosa cases. Previous studies have shown that RPGR plays a critical role in ciliary protein transport. However, the precise mechanisms of disease triggered by RPGR ORF15 mutations have yet to be clearly defined. There are two homologous genes in zebrafish, rpgra and rpgrb. Zebrafish rpgra has a single transcript homologous to human RPGR ORF15; rpgrb has two major transcripts: rpgrb ex1-17 and rpgrb ORF15, similar to human RPGR ex1-19 and RPGR ORF15, respectively. rpgrb knockdown in zebrafish resulted in both abnormal development and increased cell death in the dysplastic retina. However, the impact of knocking down rpgra in zebrafish remains undetermined. Here, we constructed a rpgra mutant zebrafish model to investigate the retina defect and related molecular mechanism. Methods: we utilized transcription activator-like effector nuclease (TALEN) to generate a rpgra mutant zebrafish. Western blot was used to determine protein expression. RT-PCR was used to quantify gene transcription levels. The visual function of embryonic zebrafish was detected by electroretinography. Immunohistochemistry was used to observe the pathological changes in the retina of mutant zebrafish and transmission electron microscope was employed to view subcellular structure of photoreceptor cells. Results: A homozygous rpgra mutant zebrafish with c.1675_1678delins21 mutation was successfully constructed. Despite the normal morphological development of the retina at 5 days post-fertilization, visual dysfunction was observed in the mutant zebrafish. Further histological and immunofluorescence assays indicated that rpgra mutant zebrafish retina photoreceptors progressively began to degenerate at 3-6 months. Additionally, the mislocalization of cone outer segment proteins (Opn1lw and Gnb3) and the accumulation of vacuole-like structures around the connecting cilium below the OSs were observed in mutant zebrafish. Furthermore, Rab8a, a key regulator of opsin-carrier vesicle trafficking, exhibited decreased expression and evident mislocalization in mutant zebrafish. Discussion: This study generated a novel rpgra mutant zebrafish model, which showed retinal degeneration. our data suggested Rpgra is necessary for the ciliary transport of cone-associated proteins, and further investigation is required to determine its function in rods. The rpgra mutant zebrafish constructed in this study may help us gain a better understanding of the molecular mechanism of retinal degeneration caused by RPGR ORF15 mutation and find some useful treatment in the future.
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Affiliation(s)
- Xiliang Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Sansure Biotech Inc., Changsha, Hunan, China
| | - Shanshan Han
- Medical College, China Three Gorges University, Yichang, China
- The Institute of Infection and Inflammation, China Three Gorges University, Yichang, Hubei, China
| | - Fei Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Science, Wuhan, Hubei, China
| | - Shanshan Yu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Visual Neuroscience and Stem Cell Engineering, College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, Hubei, China
| | - Yayun Qin
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jingzhen Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Danna Jia
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Pan Gao
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xiang Chen
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhaohui Tang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yuwen Huang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
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7
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Mathy CJP, Mishra P, Flynn JM, Perica T, Mavor D, Bolon DNA, Kortemme T. A complete allosteric map of a GTPase switch in its native cellular network. Cell Syst 2023; 14:237-246.e7. [PMID: 36801015 PMCID: PMC10173951 DOI: 10.1016/j.cels.2023.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 11/08/2022] [Accepted: 01/06/2023] [Indexed: 02/19/2023]
Abstract
Allosteric regulation is central to protein function in cellular networks. A fundamental open question is whether cellular regulation of allosteric proteins occurs only at a few defined positions or at many sites distributed throughout the structure. Here, we probe the regulation of GTPases-protein switches that control signaling through regulated conformational cycling-at residue-level resolution by deep mutagenesis in the native biological network. For the GTPase Gsp1/Ran, we find that 28% of the 4,315 assayed mutations show pronounced gain-of-function responses. Twenty of the sixty positions enriched for gain-of-function mutations are outside the canonical GTPase active site switch regions. Kinetic analysis shows that these distal sites are allosterically coupled to the active site. We conclude that the GTPase switch mechanism is broadly sensitive to cellular allosteric regulation. Our systematic discovery of new regulatory sites provides a functional map to interrogate and target GTPases controlling many essential biological processes.
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Affiliation(s)
- Christopher J P Mathy
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA; The UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Parul Mishra
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA 01605, USA; School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | - Julia M Flynn
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Tina Perica
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - David Mavor
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Daniel N A Bolon
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Tanja Kortemme
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA; The UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco, San Francisco, CA 94158, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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8
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Czigleczki J, de Resende Lara PT, Dudas B, Jang H, Perahia D, Nussinov R, Balog E. Small GTPase Ran: Depicting the nucleotide-specific conformational landscape of the functionally important C-terminus. Front Mol Biosci 2023; 10:1111574. [PMID: 36726377 PMCID: PMC9885160 DOI: 10.3389/fmolb.2023.1111574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/04/2023] [Indexed: 01/17/2023] Open
Abstract
The small GTPase Ran is the main regulator of the nucleo-cytoplasmic import and export through the nuclear pore complex. It functions as a molecular switch cycling between the GDP-bound inactive and GTP-bound active state. It consists of a globular (G) domain and a C-terminal region, which is bound to the G-domain in the inactive, GDP-bound states. Crystal structures of the GTP-bound active form complexed with Ran binding proteins (RanBP) show that the C-terminus undergoes a large conformational change, embracing Ran binding domains (RanBD). Whereas in the crystal structures of macromolecular complexes not containing RanBDs the structure of the C-terminal segment remains unresolved, indicating its large conformational flexibility. This movement could not have been followed either by experimental or simulation methods. Here, starting from the crystal structure of Ran in both GDP- and GTP-bound forms we show how rigid the C-terminal region in the inactive structure is during molecular dynamics (MD) simulations. Furthermore, we show how MD simulations of the active form are incapable of mapping the open conformations of the C-terminus. By using the MDeNM (Molecular Dynamics with excited Normal Modes) method, we were able to widely map the conformational surface of the C-terminus of Ran in the active GTP-bound form, which allows us to envisage how it can embrace RanBDs.
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Affiliation(s)
- Janka Czigleczki
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Pedro Tulio de Resende Lara
- Department of Medical Genetics and Genomic Medicine, School of Medical Sciences, University of Campinas—UNICAMP, Campinas, Brazil
| | - Balint Dudas
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary,Inserm U1268 MCTR, CiTCoM UMR 8038 CNRS—Université Paris Cité, Paris, France,Laboratoire et Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure Paris-Saclay, Gif-sur-Yvette, France
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, National Cancer Institute, Frederick, MD, United States
| | - David Perahia
- Laboratoire et Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure Paris-Saclay, Gif-sur-Yvette, France
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, National Cancer Institute, Frederick, MD, United States,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Erika Balog
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary,*Correspondence: Erika Balog,
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9
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Lokareddy RK, Hou CFD, Li F, Yang R, Cingolani G. Viral Small Terminase: A Divergent Structural Framework for a Conserved Biological Function. Viruses 2022; 14:v14102215. [PMID: 36298770 PMCID: PMC9611059 DOI: 10.3390/v14102215] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/07/2022] Open
Abstract
The genome packaging motor of bacteriophages and herpesviruses is built by two terminase subunits, known as large (TerL) and small (TerS), both essential for viral genome packaging. TerL structure, composition, and assembly to an empty capsid, as well as the mechanisms of ATP-dependent DNA packaging, have been studied in depth, shedding light on the chemo-mechanical coupling between ATP hydrolysis and DNA translocation. Instead, significantly less is known about the small terminase subunit, TerS, which is dispensable or even inhibitory in vitro, but essential in vivo. By taking advantage of the recent revolution in cryo-electron microscopy (cryo-EM) and building upon a wealth of crystallographic structures of phage TerSs, in this review, we take an inventory of known TerSs studied to date. Our analysis suggests that TerS evolved and diversified into a flexible molecular framework that can conserve biological function with minimal sequence and quaternary structure conservation to fit different packaging strategies and environmental conditions.
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10
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Abdelraheem E, Thair B, Varela RF, Jockmann E, Popadić D, Hailes HC, Ward JM, Iribarren AM, Lewkowicz ES, Andexer JN, Hagedoorn P, Hanefeld U. Methyltransferases: Functions and Applications. Chembiochem 2022; 23:e202200212. [PMID: 35691829 PMCID: PMC9539859 DOI: 10.1002/cbic.202200212] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/10/2022] [Indexed: 11/25/2022]
Abstract
In this review the current state-of-the-art of S-adenosylmethionine (SAM)-dependent methyltransferases and SAM are evaluated. Their structural classification and diversity is introduced and key mechanistic aspects presented which are then detailed further. Then, catalytic SAM as a target for drugs, and approaches to utilise SAM as a cofactor in synthesis are introduced with different supply and regeneration approaches evaluated. The use of SAM analogues are also described. Finally O-, N-, C- and S-MTs, their synthetic applications and potential for compound diversification is given.
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Affiliation(s)
- Eman Abdelraheem
- BiocatalysisDepartment of BiotechnologyDelft University of TechnologyVan der Maasweg 92629 HZDelft (TheNetherlands
| | - Benjamin Thair
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - Romina Fernández Varela
- Laboratorio de Biotransformaciones y Química de Ácidos NucleicosUniversidad Nacional de QuilmesRoque S. Peña 352B1876BXDBernalArgentina
| | - Emely Jockmann
- Institute of Pharmaceutical SciencesUniversity of FreiburgAlbertstr. 2579104FreiburgGermany
| | - Désirée Popadić
- Institute of Pharmaceutical SciencesUniversity of FreiburgAlbertstr. 2579104FreiburgGermany
| | - Helen C. Hailes
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - John M. Ward
- Department of Biochemical EngineeringBernard Katz BuildingUniversity College LondonLondonWC1E 6BTUK
| | - Adolfo M. Iribarren
- Laboratorio de Biotransformaciones y Química de Ácidos NucleicosUniversidad Nacional de QuilmesRoque S. Peña 352B1876BXDBernalArgentina
| | - Elizabeth S. Lewkowicz
- Laboratorio de Biotransformaciones y Química de Ácidos NucleicosUniversidad Nacional de QuilmesRoque S. Peña 352B1876BXDBernalArgentina
| | - Jennifer N. Andexer
- Institute of Pharmaceutical SciencesUniversity of FreiburgAlbertstr. 2579104FreiburgGermany
| | - Peter‐Leon Hagedoorn
- BiocatalysisDepartment of BiotechnologyDelft University of TechnologyVan der Maasweg 92629 HZDelft (TheNetherlands
| | - Ulf Hanefeld
- BiocatalysisDepartment of BiotechnologyDelft University of TechnologyVan der Maasweg 92629 HZDelft (TheNetherlands
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11
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The intricate roles of RCC1 in normal cells and cancer cells. Biochem Soc Trans 2022; 50:83-93. [PMID: 35191966 DOI: 10.1042/bst20210861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/24/2022] [Accepted: 02/02/2022] [Indexed: 11/17/2022]
Abstract
RCC1 (regulator of chromosome condensation 1) is a highly conserved chromatin-binding protein and the only known guanine-nucleotide exchange factor of Ran (a nuclear Ras homolog). RCC1 plays an essential role in the regulation of cell cycle-related activities such as nuclear envelope formation, nuclear pore complex and spindle assembly, and nucleocytoplasmic transport. Over the last decade, increasing evidence has emerged highlighting the potential relevance of RCC1 to carcinogenesis, especially cervical, lung, and breast cancer. In this review, we briefly discuss the roles of RCC1 in both normal and tumor cells based on articles published in recent years, followed by a brief overview of future perspectives in the field.
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12
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Li T, Guo Y. ADP-Ribosylation Factor Family of Small GTP-Binding Proteins: Their Membrane Recruitment, Activation, Crosstalk and Functions. Front Cell Dev Biol 2022; 10:813353. [PMID: 35186926 PMCID: PMC8850633 DOI: 10.3389/fcell.2022.813353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/14/2022] [Indexed: 11/13/2022] Open
Abstract
Members of the ADP-ribosylation factor (ARF) family of guanine-nucleotide binding proteins play critical roles in various cellular processes, especially in regulating the secretory, and endocytic pathways. The fidelity of intracellular vesicular trafficking depends on proper activations and precise subcellular distributions of ARF family proteins regulated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Here we review recent progress in understanding the membrane recruitment, activation, crosstalk, and functions of ARF family proteins.
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Affiliation(s)
- Tiantian Li
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Yusong Guo
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- Hong Kong University of Science and Technology, Shenzhen Research Institute, Shenzhen, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- *Correspondence: Yusong Guo,
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13
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Boudhraa Z, Zaoui K, Fleury H, Cahuzac M, Gilbert S, Tchakarska G, Kendall-Dupont J, Carmona E, Provencher D, Mes-Masson AM. NR1D1 regulation by Ran GTPase via miR4472 identifies an essential vulnerability linked to aneuploidy in ovarian cancer. Oncogene 2021; 41:309-320. [PMID: 34743206 PMCID: PMC8755527 DOI: 10.1038/s41388-021-02082-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/06/2021] [Accepted: 10/14/2021] [Indexed: 12/12/2022]
Abstract
While aneuploidy is a main enabling characteristic of cancers, it also creates specific vulnerabilities. Here we demonstrate that Ran inhibition targets epithelial ovarian cancer (EOC) survival through its characteristic aneuploidy. We show that induction of aneuploidy in rare diploid EOC cell lines or normal cells renders them highly dependent on Ran. We also establish an inverse correlation between Ran and the tumor suppressor NR1D1 and reveal the critical role of Ran/NR1D1 axis in aneuploidy-associated endogenous DNA damage repair. Mechanistically, we show that Ran, through the maturation of miR4472, destabilizes the mRNA of NR1D1 impacting several DNA repair pathways. We showed that NR1D1 interacts with both PARP1 and BRCA1 leading to the inhibition of DNA repair. Concordantly, loss of Ran was associated with NR1D1 induction, accumulation of DNA damages, and lethality of aneuploid EOC cells. Our findings suggest a synthetic lethal strategy targeting aneuploid cells based on their dependency to Ran.
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Affiliation(s)
- Zied Boudhraa
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du cancer de Montréal (ICM), Montreal, QC, Canada
| | - Kossay Zaoui
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du cancer de Montréal (ICM), Montreal, QC, Canada
| | - Hubert Fleury
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du cancer de Montréal (ICM), Montreal, QC, Canada
| | - Maxime Cahuzac
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du cancer de Montréal (ICM), Montreal, QC, Canada
| | - Sophie Gilbert
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du cancer de Montréal (ICM), Montreal, QC, Canada
| | - Guergana Tchakarska
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du cancer de Montréal (ICM), Montreal, QC, Canada
| | - Jennifer Kendall-Dupont
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du cancer de Montréal (ICM), Montreal, QC, Canada
| | - Euridice Carmona
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du cancer de Montréal (ICM), Montreal, QC, Canada
| | - Diane Provencher
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du cancer de Montréal (ICM), Montreal, QC, Canada.,Division of Gynecologic Oncology, Université de Montréal, Montreal, QC, Canada
| | - Anne-Marie Mes-Masson
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada. .,Institut du cancer de Montréal (ICM), Montreal, QC, Canada. .,Department of Medicine, Université de Montréal, Montreal, QC, Canada.
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14
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Lee CH, Hawker NP, Peters JR, Lonhienne TGA, Gursanscky NR, Matthew L, Brosnan CA, Mann CWG, Cromer L, Taochy C, Ngo QA, Sundaresan V, Schenk PM, Kobe B, Borges F, Mercier R, Bowman JL, Carroll BJ. DEFECTIVE EMBRYO AND MERISTEMS genes are required for cell division and gamete viability in Arabidopsis. PLoS Genet 2021; 17:e1009561. [PMID: 33999950 PMCID: PMC8158957 DOI: 10.1371/journal.pgen.1009561] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/27/2021] [Accepted: 04/21/2021] [Indexed: 11/19/2022] Open
Abstract
The DEFECTIVE EMBRYO AND MERISTEMS 1 (DEM1) gene encodes a protein of unknown biochemical function required for meristem formation and seedling development in tomato, but it was unclear whether DEM1’s primary role was in cell division or alternatively, in defining the identity of meristematic cells. Genome sequence analysis indicates that flowering plants possess at least two DEM genes. Arabidopsis has two DEM genes, DEM1 and DEM2, which we show are expressed in developing embryos and meristems in a punctate pattern that is typical of genes involved in cell division. Homozygous dem1 dem2 double mutants were not recovered, and plants carrying a single functional DEM1 allele and no functional copies of DEM2, i.e. DEM1/dem1 dem2/dem2 plants, exhibit normal development through to the time of flowering but during male reproductive development, chromosomes fail to align on the metaphase plate at meiosis II and result in abnormal numbers of daughter cells following meiosis. Additionally, these plants show defects in both pollen and embryo sac development, and produce defective male and female gametes. In contrast, dem1/dem1 DEM2/dem2 plants showed normal levels of fertility, indicating that DEM2 plays a more important role than DEM1 in gamete viability. The increased importance of DEM2 in gamete viability correlated with higher mRNA levels of DEM2 compared to DEM1 in most tissues examined and particularly in the vegetative shoot apex, developing siliques, pollen and sperm. We also demonstrate that gamete viability depends not only on the number of functional DEM alleles inherited following meiosis, but also on the number of functional DEM alleles in the parent plant that undergoes meiosis. Furthermore, DEM1 interacts with RAS-RELATED NUCLEAR PROTEIN 1 (RAN1) in yeast two-hybrid and pull-down binding assays, and we show that fluorescent proteins fused to DEM1 and RAN1 co-localize transiently during male meiosis and pollen development. In eukaryotes, RAN is a highly conserved GTPase that plays key roles in cell cycle progression, spindle assembly during cell division, reformation of the nuclear envelope following cell division, and nucleocytoplasmic transport. Our results demonstrate that DEM proteins play an essential role in cell division in plants, most likely through an interaction with RAN1. Up to half of the genes predicted from genome projects lack a known biological and biochemical function. Many of these genes are likely to play essential roles but it is difficult to reveal their function because minor changes in the genetic sequence can result in lethality and genetic redundancy can obscure analysis. Genome projects predict that flowering plants have at least two DEM genes that encode a protein of unknown cellular and biochemical function. In this paper, we use multiple combinations of dem mutants in Arabidopsis to show that DEM genes are essential for cell division and gamete viability. Interestingly, gamete viability depends not only on the number of functional copies of DEM genes in the gametes, but also on the number of functional copies of DEM genes in the parent plant that produces the gametes. We also show that DEM proteins interact with RAN, a highly conserved protein that controls cell division in all eukaryotic organisms.
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Affiliation(s)
- Chin Hong Lee
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia
| | - Nathaniel P. Hawker
- Section of Plant Biology, One Shields Avenue, University of California at Davis, Davis, California, United States of America
| | - Jonathan R. Peters
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia
| | - Thierry G. A. Lonhienne
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia
| | - Nial R. Gursanscky
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia
| | - Louisa Matthew
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia
| | - Christopher A. Brosnan
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia
| | - Christopher W. G. Mann
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia
| | - Laurence Cromer
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Christelle Taochy
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Quy A. Ngo
- Section of Plant Biology, One Shields Avenue, University of California at Davis, Davis, California, United States of America
| | - Venkatesan Sundaresan
- Section of Plant Biology, One Shields Avenue, University of California at Davis, Davis, California, United States of America
| | - Peer M. Schenk
- School of Agriculture and Food Sciences, The University of Queensland, St. Lucia, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia
- Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Australia
| | - Filipe Borges
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Raphael Mercier
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - John L. Bowman
- Section of Plant Biology, One Shields Avenue, University of California at Davis, Davis, California, United States of America
- School of Biological Sciences, Monash University, Clayton Campus, Clayton, Victoria, Australia
- * E-mail: (JLB); (BJC)
| | - Bernard J. Carroll
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia
- * E-mail: (JLB); (BJC)
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15
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Kalita J, Kapinos LE, Lim RYH. On the asymmetric partitioning of nucleocytoplasmic transport - recent insights and open questions. J Cell Sci 2021; 134:239102. [PMID: 33912945 DOI: 10.1242/jcs.240382] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Macromolecular cargoes are asymmetrically partitioned in the nucleus or cytoplasm by nucleocytoplasmic transport (NCT). At the center of this activity lies the nuclear pore complex (NPC), through which soluble factors circulate to orchestrate NCT. These include cargo-carrying importin and exportin receptors from the β-karyopherin (Kapβ) family and the small GTPase Ran, which switches between guanosine triphosphate (GTP)- and guanosine diphosphate (GDP)-bound forms to regulate cargo delivery and compartmentalization. Ongoing efforts have shed considerable light on how these soluble factors traverse the NPC permeability barrier to sustain NCT. However, this does not explain how importins and exportins are partitioned in the cytoplasm and nucleus, respectively, nor how a steep RanGTP-RanGDP gradient is maintained across the nuclear envelope. In this Review, we peel away the multiple layers of control that regulate NCT and juxtapose unresolved features against known aspects of NPC function. Finally, we discuss how NPCs might function synergistically with Kapβs, cargoes and Ran to establish the asymmetry of NCT.
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Affiliation(s)
- Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Larisa E Kapinos
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Roderick Y H Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
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16
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Joiner AMN, Fromme JC. Structural basis for the initiation of COPII vesicle biogenesis. Structure 2021; 29:859-872.e6. [PMID: 33831355 DOI: 10.1016/j.str.2021.03.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/09/2021] [Accepted: 03/16/2021] [Indexed: 12/19/2022]
Abstract
The first stage of the eukaryotic secretory pathway is the packaging of cargo proteins into coat protein complex II (COPII) vesicles exiting the ER. The cytoplasmic COPII vesicle coat machinery is recruited to the ER membrane by the activated, GTP-bound, form of the conserved Sar1 GTPase. Activation of Sar1 on the surface of the ER by Sec12, a membrane-anchored GEF (guanine nucleotide exchange factor), is therefore the initiating step of the secretory pathway. Here we report the structure of the complex between Sar1 and the cytoplasmic GEF domain of Sec12, both from Saccharomyces cerevisiae. This structure, representing a key nucleotide-free activation intermediate, reveals how the potassium ion-binding K loop disrupts the nucleotide-binding site of Sar1. We propose an unexpected orientation of the GEF domain relative to the membrane surface and postulate a mechanism for how Sec12 facilitates membrane insertion of the amphipathic helix exposed by Sar1 upon GTP binding.
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Affiliation(s)
- Aaron M N Joiner
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14850, USA
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14850, USA.
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17
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Zhou J, Tan Y, Zhang Y, Tong A, Shen X, Sun X, Jia D, Sun Q. GEF-independent Ran activation shifts a fraction of the protein to the cytoplasm and promotes cell proliferation. MOLECULAR BIOMEDICINE 2020; 1:18. [PMID: 35006421 PMCID: PMC8607414 DOI: 10.1186/s43556-020-00011-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 09/29/2020] [Indexed: 02/08/2023] Open
Abstract
Ran (Ras-related nuclear protein) plays several important roles in nucleo-cytoplasmic transport, mitotic spindle formation, nuclear envelope/nuclear pore complex assembly, and other functions in the cytoplasm, as well as in cellular transformation when switched on. Unlike other members of the GTPase superfamily, Ran binds more tightly to GDP than to GTP due to the presence of an auto-inhibitory C-terminal tail. Multiple missense mutations in the C-terminus of Ran occur in cancers, but their biological significance remains unclear. Here, the quantitative GDP/GTP binding preference of four engineered mutations with unstable C-termini was analyzed using a devised mant-GDP dissociation assay. The results showed that the impact of different C-terminal mutations depends on multiple factors. Although these mutants were more GTP-loaded in human cells, they were shown to be more cytoplasmic, and to support nuclear transport with minimally or partially reduced efficiency. Further, several Ran cancer mutants were compromised in autoinhibition, slightly more GTP-bound, more cytoplasmic, and enhanced the proliferation of A549 and HeLa cells in vitro. Thus, our work reveals a new route of Ran activation independent of guanine nucleotide exchange factor (GEF), which may account for the hyper-proliferation induced by Ran cancer mutations.
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Affiliation(s)
- Jinhan Zhou
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China
| | - Yuping Tan
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China
| | - Yuqing Zhang
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China
| | - Aiping Tong
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China
| | - Xiaofei Shen
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, Division of Neurology, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiaodong Sun
- Department of Pharmacology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, Division of Neurology, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
| | - Qingxiang Sun
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China.
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18
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Ren X, Jiang K, Zhang F. The Multifaceted Roles of RCC1 in Tumorigenesis. Front Mol Biosci 2020; 7:225. [PMID: 33102517 PMCID: PMC7522611 DOI: 10.3389/fmolb.2020.00225] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/11/2020] [Indexed: 01/31/2023] Open
Abstract
RCC1 (regulator of chromosome condensation 1) is the only known guanine nucleotide exchange factor of Ran, a nuclear Ras-like G protein. RCC1 combines with chromatin and Ran to establish a concentration gradient of RanGTP, thereby participating in a series of cell physiological activities. In this review, we discuss the structure of RCC1 and describe how RCC1 affects the formation and function of the nuclear envelope, spindle formation, and nuclear transport. We mainly focus on the effect of RCC1 on the cell cycle during tumorigenesis and the recent research progress that has been made in relation to different tumor types.
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Affiliation(s)
- Xuanqi Ren
- College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Kai Jiang
- College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Feng Zhang
- College of Life Sciences, Shanghai Normal University, Shanghai, China
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19
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Liu H, Fu H, Shao X, Cai W, Chipot C. Accurate Description of Cation-π Interactions in Proteins with a Nonpolarizable Force Field at No Additional Cost. J Chem Theory Comput 2020; 16:6397-6407. [PMID: 32852943 DOI: 10.1021/acs.jctc.0c00637] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cation-π interactions play a significant role in a host of processes eminently relevant to biology. However, polarization effects arising from the interaction of cations with aromatic moieties have long been recognized to be inadequately described by pairwise additive force fields. In the present work, we address this longstanding shortcoming through the nonbonded FIX (NBFIX) feature of the CHARMM36 force field, modifying pair-specific Lennard-Jones (LJ) parameters, while circumventing the limitations of the Lorentz-Berthelot combination rules. The potentials of mean force (PMFs) characterizing prototypical cation-π interactions in aqueous solutions are first determined using a hybrid quantum mechanical/molecular mechanics (QM/MM) strategy in conjunction with an importance-sampling algorithm. The LJ parameters describing the cation-π pairs are then optimized to match the QM/MM PMFs. The standard binding free energies of nine cation-π complexes, i.e., toluene, para-cresol, and 3-methyl-indole interacting with either ammonium, guanidinium, or tetramethylammonium, determined with this new set of parameters agree well with the experimental measurements. Additional simulations were carried out on three different classes of biological objects featuring cation-π interactions, including five individual proteins, three protein-ligand complexes, and two protein-protein complexes. Our results indicate that the description of cation-π interactions is overall improved using NBFIX corrections, compared with the standard pairwise additive force field. Moreover, an accurate binding free energy calculation for a protein-ligand complex containing cation-π interactions (2BOK) shows that using the new parameters, the experimental binding affinity can be reproduced quantitatively. Put together, the present work suggests that the NBFIX parameters optimized here can be broadly utilized in the simulation of proteins in an aqueous solution to enhance the representation of cation-π interactions, at no additional computational cost.
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Affiliation(s)
- Han Liu
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Haohao Fu
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Xueguang Shao
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, China.,State Key Laboratory of Medicinal Chemical Biology, Tianjin 300071, China
| | - Wensheng Cai
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Christophe Chipot
- Laboratoire International Associé CNRS and University of Illinois at Urbana-Champaign, UMR n°7019, Université de Lorraine, BP 70239, F-54506 Vandoeuvre-lès-Nancy, France.,Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801, United States
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20
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Reyes A, Favia P, Vidoni S, Petruzzella V, Zeviani M. RCC1L (WBSCR16) isoforms coordinate mitochondrial ribosome assembly through their interaction with GTPases. PLoS Genet 2020; 16:e1008923. [PMID: 32735630 PMCID: PMC7423155 DOI: 10.1371/journal.pgen.1008923] [Citation(s) in RCA: 7] [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: 02/06/2020] [Revised: 08/12/2020] [Accepted: 06/10/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial translation defects can be due to mutations affecting mitochondrial- or nuclear-encoded components. The number of known nuclear genes involved in mitochondrial translation has significantly increased in the past years. RCC1L (WBSCR16), a putative GDP/GTP exchange factor, has recently been described to interact with the mitochondrial large ribosomal subunit. In humans, three different RCC1L isoforms have been identified that originate from alternative splicing but share the same N-terminus, RCC1LV1, RCC1LV2 and RCC1LV3. All three isoforms were exclusively localized to mitochondria, interacted with its inner membrane and could associate with homopolymeric oligos to different extent. Mitochondrial immunoprecipitation experiments showed that RCC1LV1 and RCC1LV3 associated with the mitochondrial large and small ribosomal subunit, respectively, while no significant association was observed for RCC1LV2. Overexpression and silencing of RCC1LV1 or RCC1LV3 led to mitoribosome biogenesis defects that resulted in decreased translation. Indeed, significant changes in steady-state levels and distribution on isokinetic sucrose gradients were detected not only for mitoribosome proteins but also for GTPases, (GTPBP10, ERAL1 and C4orf14), and pseudouridylation proteins, (TRUB2, RPUSD3 and RPUSD4). All in all, our data suggest that RCC1L is essential for mitochondrial function and that the coordination of at least two isoforms is essential for proper ribosomal assembly.
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Affiliation(s)
- Aurelio Reyes
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
| | - Paola Favia
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
- Dipartimento di Scienze Mediche di Base, Neuroscienze e Organi di Senso - Università degli Studi Aldo Moro, Piazza G. Cesare, Bari, Italy
| | - Sara Vidoni
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Vittoria Petruzzella
- Dipartimento di Scienze Mediche di Base, Neuroscienze e Organi di Senso - Università degli Studi Aldo Moro, Piazza G. Cesare, Bari, Italy
| | - Massimo Zeviani
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
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21
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Chen Q, Jiang P, Jia B, Liu Y, Zhang Z. RCC2 contributes to tumor invasion and chemoresistance to cisplatin in hepatocellular carcinoma. Hum Cell 2020; 33:709-720. [PMID: 32239438 DOI: 10.1007/s13577-020-00353-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 03/22/2020] [Indexed: 12/21/2022]
Abstract
Tumor metastasis and chemoresistance are the main causes of treatment failure and high mortality in hepatocellular carcinoma (HCC). Therefore, it is critical to clarify the biological action and potential mechanisms in HCC cells to develop novel therapeutics. The regulator of chromosome condensation 2 (RCC2), a component of the chromosomal passenger complex, was shown to have important roles in tumor development and radio-chemotherapy resistance. However, its role in the aggressive phenotypes and cisplatin (DDP)-resistance of HCC is not known. Therefore, this study aimed to investigate the role of RCC2 in HCC pathogenesis. Interestingly, we found that RCC2 was upregulated in HCC patient specimens and HCC cell lines and was correlated with the pathological grade of HCC. To evaluate the function of RCC2 in HCC cell, lentivirus vector-based shRNAs were transfected into HCC cells. Silencing RCC2 inhibited the HCC cell proliferation, migration, invasion, and increased the apoptosis rate upon DDP treatment. Further analysis showed that RCC2-mediated downregulation of the expression of survival proteins occurred via the AKT and Bcl2 pathways. Our results suggest that RCC2 might act as an oncogenic protein promoting metastatic behaviors and cisplatin resistance in HCC cells, and thereby could be a potential prognostic biomarker and therapeutic target for HCC.
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Affiliation(s)
- Qingmin Chen
- Department of General Surgery, The First Hospital of Jilin University, Changchun, 130021, Jilin, China
| | - Peiqiang Jiang
- Department of General Surgery, The First Hospital of Jilin University, Changchun, 130021, Jilin, China
| | - Baoxing Jia
- Department of General Surgery, The First Hospital of Jilin University, Changchun, 130021, Jilin, China
| | - Yahui Liu
- Department of General Surgery, The First Hospital of Jilin University, Changchun, 130021, Jilin, China.
| | - Ze Zhang
- Department of General Surgery, The First Hospital of Jilin University, Changchun, 130021, Jilin, China.
- Department of Hepatobiliary-Pancreatic Surgery, China-Japan Union Hospital of Jilin University, 126 Xiantai Street, Changchun, 130000, Jilin, China.
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22
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Boudhraa Z, Carmona E, Provencher D, Mes-Masson AM. Ran GTPase: A Key Player in Tumor Progression and Metastasis. Front Cell Dev Biol 2020; 8:345. [PMID: 32528950 PMCID: PMC7264121 DOI: 10.3389/fcell.2020.00345] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Abstract
Ran (Ras-related nuclear protein) GTPase is a member of the Ras superfamily. Like all the GTPases, Ran cycles between an active (GTP-bound) and inactive (GDP-bound) state. However, Ran lacks the CAAX motif at its C-terminus, a feature of other small GTPases that ensures a plasma membrane localization, and largely traffics between the nucleus and the cytoplasm. Ran regulates nucleo-cytoplasmic transport of molecules through the nuclear pore complex and controls cell cycle progression through the regulation of microtubule polymerization and mitotic spindle formation. The disruption of Ran expression has been linked to cancer at different levels - from cancer initiation to metastasis. In the present review, we discuss the contribution of Ran in the acquisition of three hallmarks of cancer, namely, proliferative signaling, resistance to apoptosis, and invasion/metastasis, and highlight its prognostic value in cancer patients. In addition, we discuss the use of this GTPase as a therapeutic target in cancer.
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Affiliation(s)
- Zied Boudhraa
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada
| | - Euridice Carmona
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada
| | - Diane Provencher
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada.,Division of Gynecologic Oncology, Université de Montréal, Montreal, QC, Canada
| | - Anne-Marie Mes-Masson
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada
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23
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Barbato S, Kapinos LE, Rencurel C, Lim RYH. Karyopherin enrichment at the nuclear pore complex attenuates Ran permeability. J Cell Sci 2020; 133:jcs238121. [PMID: 31932502 DOI: 10.1242/jcs.238121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 12/13/2019] [Indexed: 12/25/2022] Open
Abstract
Ran is a small GTPase whose nucleotide-bound forms cycle through nuclear pore complexes (NPCs) to direct nucleocytoplasmic transport (NCT). Generally, Ran guanosine triphosphate (RanGTP) binds cargo-carrying karyopherin receptors (Kaps) in the nucleus and releases them into the cytoplasm following hydrolysis to Ran guanosine diphosphate (RanGDP). This generates a remarkably steep Ran gradient across the nuclear envelope that sustains compartment-specific cargo delivery and accumulation. However, because NPCs are permeable to small molecules of comparable size, it is unclear how an uncontrolled mixing of RanGTP and RanGDP is prevented. Here, we find that an NPC-enriched pool of karyopherin subunit beta 1 (KPNB1, hereafter referred to as Kapβ1) selectively mediates Ran diffusion across the pore but not passive molecules of similar size (e.g. GFP). This is due to RanGTP having a stronger binding interaction with Kapβ1 than RanGDP. For this reason, the RanGDP importer, nuclear transport factor 2, facilitates the return of RanGDP into the nucleus following GTP hydrolysis. Accordingly, the enrichment of Kapβ1 at NPCs may function as a retention mechanism that preserves the sharp transition of RanGTP and RanGDP in the nucleus and cytoplasm, respectively.
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Affiliation(s)
- Suncica Barbato
- Biozentrum & The Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Larisa E Kapinos
- Biozentrum & The Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Chantal Rencurel
- Biozentrum & The Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Roderick Y H Lim
- Biozentrum & The Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
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24
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Structural Insights into the Regulation Mechanism of Small GTPases by GEFs. Molecules 2019; 24:molecules24183308. [PMID: 31514408 PMCID: PMC6767298 DOI: 10.3390/molecules24183308] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 12/12/2022] Open
Abstract
Small GTPases are key regulators of cellular events, and their dysfunction causes many types of cancer. They serve as molecular switches by cycling between inactive guanosine diphosphate (GDP)-bound and active guanosine triphosphate (GTP)-bound states. GTPases are deactivated by GTPase-activating proteins (GAPs) and are activated by guanine-nucleotide exchange factors (GEFs). The intrinsic GTP hydrolysis activity of small GTPases is generally low and is accelerated by GAPs. GEFs promote GDP dissociation from small GTPases to allow for GTP binding, which results in a conformational change of two highly flexible segments, called switch I and switch II, that enables binding of the gamma phosphate and allows small GTPases to interact with downstream effectors. For several decades, crystal structures of many GEFs and GAPs have been reported and have shown tremendous structural diversity. In this review, we focus on the latest structural studies of GEFs. Detailed pictures of the variety of GEF mechanisms at atomic resolution can provide insights into new approaches for drug discovery.
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25
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Bao X, Liu H, Liu X, Ruan K, Zhang Y, Zhang Z, Hu Q, Liu Y, Akram S, Zhang J, Gong Q, Wang W, Yuan X, Li J, Zhao L, Dou Z, Tian R, Yao X, Wu J, Shi Y. Mitosis-specific acetylation tunes Ran effector binding for chromosome segregation. J Mol Cell Biol 2019; 10:18-32. [PMID: 29040603 PMCID: PMC6041754 DOI: 10.1093/jmcb/mjx045] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 10/03/2017] [Indexed: 11/12/2022] Open
Abstract
Stable transmission of genetic information during cell division requires faithful mitotic spindle assembly and chromosome segregation. The Ran GTPase plays a key role in mitotic spindle assembly. However, how the generation of a chemical gradient of Ran-GTP at the spindle is coupled to mitotic post-translational modifications has never been characterized. Here, we solved the complex structure of Ran with the nucleotide release factor Mog1 and delineated a novel mitosis-specific acetylation-regulated Ran-Mog1 interaction during chromosome segregation. Our structure-guided functional analyses revealed that Mog1 competes with RCC1 for Ran binding in a GTP/GDP-dependent manner. Biochemical characterization demonstrated that Mog1-bound Ran prevents RCC1 binding and subsequent GTP loading. Surprisingly, Ran is a bona fide substrate of TIP60, and the acetylation of Lys134 by TIP60 liberates Mog1 from Ran binding during mitosis. Importantly, this acetylation-elicited switch of Ran binding to RCC1 promotes high level of Ran-GTP, which is essential for chromosome alignment. These results establish a previously uncharacterized regulatory mechanism in which TIP60 provides a homeostatic control of Ran-GTP level by tuning Ran effector binding for chromosome segregation in mitosis.
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Affiliation(s)
- Xiaoling Bao
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Heng Liu
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Xing Liu
- Center of Excellence in Molecular Cell Sciences, Chinese Academy of Sciences & Anhui Key Laboratory for Cellular Dynamics and Chemical Biology, Hefei 230027, China
| | - Ke Ruan
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Yonghui Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Zhiyong Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Qi Hu
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Ying Liu
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Saima Akram
- Center of Excellence in Molecular Cell Sciences, Chinese Academy of Sciences & Anhui Key Laboratory for Cellular Dynamics and Chemical Biology, Hefei 230027, China
| | - Jiahai Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Qingguo Gong
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Wenwen Wang
- Center of Excellence in Molecular Cell Sciences, Chinese Academy of Sciences & Anhui Key Laboratory for Cellular Dynamics and Chemical Biology, Hefei 230027, China
| | - Xiao Yuan
- Southern University of Science & Technology, Shenzhen 518055, China
| | - Jian Li
- Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Lingli Zhao
- Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Zhen Dou
- Center of Excellence in Molecular Cell Sciences, Chinese Academy of Sciences & Anhui Key Laboratory for Cellular Dynamics and Chemical Biology, Hefei 230027, China
| | - Ruijun Tian
- Southern University of Science & Technology, Shenzhen 518055, China
| | - Xuebiao Yao
- Center of Excellence in Molecular Cell Sciences, Chinese Academy of Sciences & Anhui Key Laboratory for Cellular Dynamics and Chemical Biology, Hefei 230027, China
| | - Jihui Wu
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Yunyu Shi
- Hefei National Laboratory for Physical Sciences at Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
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26
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Identification of the guanine nucleotide exchange factor for SAR1 in the filamentous fungal model Aspergillus nidulans. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118551. [PMID: 31487505 DOI: 10.1016/j.bbamcr.2019.118551] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/02/2019] [Accepted: 08/11/2019] [Indexed: 12/30/2022]
Abstract
In spite of its basic and applied interest, the regulation of ER exit by filamentous fungi is insufficiently understood. In previous work we isolated a panel of conditional mutations in sarA encoding the master GTPase SarASAR1 in A. nidulans and demonstrated its key role in exocytosis and hyphal morphogenesis. However, the SAR1 guanine nucleotide exchange factor (GEF), Sec12, has not been characterized in any filamentous fungus, largely due to the fact that SEC12 homologues share little amino acid sequence identity beyond a GGGGxxxxGϕxN motif involved in guanine nucleotide exchange. Here we demonstrate that AN11127 encodes A. nidulans Sec12, which is an essential protein that localizes to the ER and that, when overexpressed, rescues the growth defect resulting from a hypomorphic sarA6ts mutation at 37 °C. Using purified, bacterially expressed proteins we demonstrate that the product of AN11127 accelerates nucleotide exchange on SarASAR1, but not on its closely related GTPase ArfAARF1, as expected for a bona fide GEF. The unequivocal characterization of A. nidulans Sec12 paves the way for the tailored modification of ER exit in a model organism that is closely related to industrial species of filamentous fungi.
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27
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Khanna H. More Than Meets the Eye: Current Understanding of RPGR Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1074:521-538. [PMID: 29721984 DOI: 10.1007/978-3-319-75402-4_64] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
This article summarizes the recent advances in our understanding of a major retinal disease gene RPGR (retinitis pigmentosa GTPase regulator), mutations in which are associated with majority of X-linked forms of retinal degenerations. A great deal of work has been done to uncover the ciliary localization of RPGR and its interacting proteins in the retina. However, the molecular mechanisms of action of RPGR in the photoreceptors are still unclear. Recent studies have begun to shed light on the intracellular pathways in which RPGR is likely involved. The deregulation of such pathways may underlie the pathogenesis of severe retinal degeneration associated with RPGR. With the recent advances in the gene augmentation therapy for RPGR-associated disease, there is a lot of excitement in the field. Patients with RPGR mutations, however, present with clinically heterogeneous manifestations. It is therefore imperative to examine the function of RPGR in detail, so that we can design patient-oriented therapeutic strategies for this disease.
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Affiliation(s)
- Hemant Khanna
- Department of Ophthalmology and Neurobiology, UMASS Medical School, Worcester, MA, USA.
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28
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Lin S, Yu L, Zhang H. Transcriptomic Responses to Thermal Stress and Varied Phosphorus Conditions in Fugacium kawagutii. Microorganisms 2019; 7:microorganisms7040096. [PMID: 30987028 PMCID: PMC6517890 DOI: 10.3390/microorganisms7040096] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 03/18/2019] [Accepted: 03/30/2019] [Indexed: 01/08/2023] Open
Abstract
Coral reef-associated Symbiodiniaceae live in tropical and oligotrophic environments and are prone to heat and nutrient stress. How their metabolic pathways respond to pulses of warming and phosphorus (P) depletion is underexplored. Here, we conducted RNA-seq analysis to investigate transcriptomic responses to thermal stress, phosphate deprivation, and organic phosphorus (OP) replacement in Fugacium kawagutii. Using dual-algorithm (edgeR and NOIseq) to remedy the problem of no replicates, we conservatively found 357 differentially expressed genes (DEGs) under heat stress, potentially regulating cell wall modulation and the transport of iron, oxygen, and major nutrients. About 396 DEGs were detected under P deprivation and 671 under OP utilization, both mostly up-regulated and potentially involved in photosystem and defensome, despite different KEGG pathway enrichments. Additionally, we identified 221 genes that showed relatively stable expression levels across all conditions (likely core genes), mostly catalytic and binding proteins. This study reveals a wide range of, and in many cases previously unrecognized, molecular mechanisms in F. kawagutii to cope with heat stress and phosphorus-deficiency stress. Their quantitative expression dynamics, however, requires further verification with triplicated experiments, and the data reported here only provide clues for generating testable hypotheses about molecular mechanisms underpinning responses and adaptation in F. kawagutii to temperature and nutrient stresses.
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Affiliation(s)
- Senjie Lin
- Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA.
| | - Liying Yu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, China.
| | - Huan Zhang
- Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA.
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29
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Kang N, Liu J, Zhao Y. Dissociation mechanism of GDP from Cdc42 via DOCK9 revealed by molecular dynamics simulations. Proteins 2019; 87:433-442. [PMID: 30714195 DOI: 10.1002/prot.25665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 01/28/2019] [Accepted: 01/31/2019] [Indexed: 12/18/2022]
Abstract
Cell division control protein 42 homolog (Cdc42) influences a variety of cellular responses such as cell migration and polarity. Deregulation of Cdc42 has been associated with several human diseases and developmental disorders. Over-activation of Cdc42 through guanine nucleotide exchange factor (GEF) is a critical event for Cdc42 involved cancer metastasis. Members of DOCK family of GEF are important activators of Cdc42. However, this activation mechanism is still unknown. Molecular dynamics (MD) simulations and molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) calculations were employed to investigate the central step of the activation of Cdc42: the dissociation mechanism of GDP from Cdc42 via DOCK9. Simulation results show that Mg2+ ion has a remarkable influence on the conformational change of switch I of Cdc42 through residue Pro34 which functions as a "clasp" to control the flexibility of switch I. In the GDP dissociation process, the Mg2+ ion leave first to result in a suitable conformation of Cdc42 for following DOCK9 binding to. When DOCK9 binds to Cdc42, it changes the orientations of residues Lys16, Thr17, Cys18 and Phe28 of Cdc42 to weaken the interactions between Cdc42 and GDP to release GDP. This study first elucidates the dissociation mechanism of GDP from Cdc42 via DOCK9 and identifies the essential residues of Cdc42 in this process. These simulation results are consistent with the recent findings of biochemical and amino acid mutational studies, and the observations are beneficial to understand the activation mechanism of Cdc42 and to provide insights for designing compounds targeting on Cdc42 related cancer metastasis.
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Affiliation(s)
- Ning Kang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Jiansheng Liu
- Department of Neurology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yaxue Zhao
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
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30
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Abstract
Protein α‐N‐terminal methylation is catalyzed by protein N‐terminal methyltransferases. The prevalent occurrence of this methylation in ribosomes, myosin, and histones implies its function in protein–protein interactions. Although its full spectrum of function has not yet been outlined, recent discoveries have revealed the emerging roles of α‐N‐terminal methylation in protein–chromatin interactions, DNA damage repair, and chromosome segregation. Herein, an overview of the discovery of protein N‐terminal methyltransferases and functions of α‐N‐terminal methylation is presented. In addition, substrate recognition, mechanisms, and inhibition of N‐terminal methyltransferases are reviewed. Opportunities and gaps in protein α‐N‐terminal methylation are also discussed.
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Affiliation(s)
- Rong Huang
- Department of Medicinal Chemistry and Molecular PharmacologyCenter for Cancer Research, Institute for Drug DiscoveryPurdue University West Lafayette IN 47907 USA
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31
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Bootsma AN, Wheeler SE. Tuning Stacking Interactions between Asp-Arg Salt Bridges and Heterocyclic Drug Fragments. J Chem Inf Model 2018; 59:149-158. [PMID: 30507185 DOI: 10.1021/acs.jcim.8b00563] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Stacking interactions can play an integral role in the strength and selectivity of protein-drug binding and are of particular interest given the ubiquity and variety of heterocyclic fragments in drugs. In addition to traditional stacking interactions between aromatic rings, stacking interactions involving heterocyclic drug fragments and protein salt bridges have also been observed. These "salt-bridge stacking interactions" can be quite strong but are not well understood. We studied stacked dimers of the acetate···guanidinium ion pair with a diverse set of 63 heterocycles using robust ab initio methods. The computed interaction energies span more than 10 kcal mol-1, indicating the sensitivity of these salt-bridge stacking interactions to heterocycle features. Trends in both the strength and preferred geometry of these interactions can be understood through analyses of the electrostatic potentials and electric fields above the heterocycles. We have developed new heterocycle descriptors that quantify these effects and used them to create robust predictors of the strength of salt-bridge stacking interactions both in the gas phase and a protein-like dielectric environment. These predictive tools, combined with a set of qualitative guidelines, should facilitate the choice of heterocycles that maximize salt-bridge stacking interactions in drug binding sites.
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Affiliation(s)
- Andrea N Bootsma
- Department of Chemistry , Texas A&M University , College Station , Texas 77842 , United States.,Center for Computational Quantum Chemistry, Department of Chemistry , University of Georgia , Athens , Georgia 30602 , United States
| | - Steven E Wheeler
- Center for Computational Quantum Chemistry, Department of Chemistry , University of Georgia , Athens , Georgia 30602 , United States
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32
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Zhang MS, Furuta M, Arnaoutov A, Dasso M. RCC1 regulates inner centromeric composition in a Ran-independent fashion. Cell Cycle 2018; 17:739-748. [PMID: 29464982 DOI: 10.1080/15384101.2018.1442630] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
RCC1 associates to chromatin dynamically within mitosis and catalyzes Ran-GTP production. Exogenous RCC1 disrupts kinetochore structure in Xenopus egg extracts (XEEs), but the molecular basis of this disruption remains unknown. We have investigated this question, utilizing replicated chromosomes that possess paired sister kinetochores. We find that exogenous RCC1 evicts a specific subset of inner KT proteins including Shugoshin-1 (Sgo1) and the chromosome passenger complex (CPC). We generated RCC1 mutants that separate its enzymatic activity and chromatin binding. Strikingly, Sgo1 and CPC eviction depended only on RCC1's chromatin affinity but not its capacity to produce Ran-GTP. RCC1 similarly released Sgo1 and CPC from synthetic kinetochores assembled on CENP-A nucleosome arrays. Together, our findings indicate RCC1 regulates kinetochores at the metaphase-anaphase transition through Ran-GTP-independent displacement of Sgo1 and CPC.
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Affiliation(s)
- Michael Shaofei Zhang
- a Division of Molecular and Cellular Biology , National Institute for Child Health and Human Development , National Institutes of Health , Bethesda , MD 20892
| | - Maiko Furuta
- a Division of Molecular and Cellular Biology , National Institute for Child Health and Human Development , National Institutes of Health , Bethesda , MD 20892
| | - Alexei Arnaoutov
- a Division of Molecular and Cellular Biology , National Institute for Child Health and Human Development , National Institutes of Health , Bethesda , MD 20892
| | - Mary Dasso
- a Division of Molecular and Cellular Biology , National Institute for Child Health and Human Development , National Institutes of Health , Bethesda , MD 20892
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33
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Gai YP, Zhao HN, Zhao YN, Zhu BS, Yuan SS, Li S, Guo FY, Ji XL. MiRNA-seq-based profiles of miRNAs in mulberry phloem sap provide insight into the pathogenic mechanisms of mulberry yellow dwarf disease. Sci Rep 2018; 8:812. [PMID: 29339758 PMCID: PMC5770470 DOI: 10.1038/s41598-018-19210-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/20/2017] [Indexed: 11/09/2022] Open
Abstract
A wide range of miRNAs have been identified as phloem-mobile molecules that play important roles in coordinating plant development and physiology. Phytoplasmas are associated with hundreds of plant diseases, and the pathogenesis involved in the interactions between phytoplasmas and plants is still poorly understood. To analyse the molecular mechanisms of phytoplasma pathogenicity, the miRNAs profiles in mulberry phloem saps were examined in response to phytoplasma infection. A total of 86 conserved miRNAs and 19 novel miRNAs were identified, and 30 conserved miRNAs and 13 novel miRNAs were differentially expressed upon infection with phytoplasmas. The target genes of the differentially expressed miRNAs are involved in diverse signalling pathways showing the complex interactions between mulberry and phytoplasma. Interestingly, we found that mul-miR482a-5p was up-regulated in the infected phloem saps, and grafting experiments showed that it can be transported from scions to rootstock. Based on the results, the complexity and roles of the miRNAs in phloem sap and the potential molecular mechanisms of their changes were discussed. It is likely that the phytoplasma-responsive miRNAs in the phloem sap modulate multiple pathways and work cooperatively in response to phytoplasma infection, and their expression changes may be responsible for some symptoms in the infected plants.
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Affiliation(s)
- Ying-Ping Gai
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Huai-Ning Zhao
- College of Forestry, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Ya-Nan Zhao
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Bing-Sen Zhu
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Shuo-Shuo Yuan
- College of Forestry, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Shuo Li
- College of Forestry, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Fang-Yue Guo
- College of Forestry, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
| | - Xian-Ling Ji
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China. .,College of Forestry, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China.
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34
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Sankhala RS, Lokareddy RK, Begum S, Pumroy RA, Gillilan RE, Cingolani G. Three-dimensional context rather than NLS amino acid sequence determines importin α subtype specificity for RCC1. Nat Commun 2017; 8:979. [PMID: 29042532 PMCID: PMC5645467 DOI: 10.1038/s41467-017-01057-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/15/2017] [Indexed: 12/27/2022] Open
Abstract
Active nuclear import of Ran exchange factor RCC1 is mediated by importin α3. This pathway is essential to generate a gradient of RanGTP on chromatin that directs nucleocytoplasmic transport, mitotic spindle assembly and nuclear envelope formation. Here we identify the mechanisms of importin α3 selectivity for RCC1. We find this isoform binds RCC1 with one order of magnitude higher affinity than the generic importin α1, although the two isoforms share an identical NLS-binding groove. Importin α3 uses its greater conformational flexibility to wedge the RCC1 β-propeller flanking the NLS against its lateral surface, preventing steric clashes with its Armadillo-core. Removing the β-propeller, or inserting a linker between NLS and β-propeller, disrupts specificity for importin α3, demonstrating the structural context rather than NLS sequence determines selectivity for isoform 3. We propose importin α3 evolved to recognize topologically complex NLSs that lie next to bulky domains or are masked by quaternary structures.Importin α3 facilitates the nuclear transport of the Ran guanine nucleotide exchange factor RCC1. Here the authors reveal the molecular basis for the selectivity of RCC1 for importin α3 vs the generic importin α1 and discuss the evolution of importin α isoforms.
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Affiliation(s)
- Rajeshwer S Sankhala
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA
| | - Ravi K Lokareddy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA
| | - Salma Begum
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA
| | - Ruth A Pumroy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA.,Department of Biochemistry, University of Utah, 15N Medical Drive East, Salt Lake City, UT, 84112-5650, USA
| | - Richard E Gillilan
- Macromolecular Diffraction Facility, Cornell High Energy Synchrotron Source (MacCHESS), Cornell University, 161 Synchrotron Drive, Ithaca, NY, 14853, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA, 19107, USA. .,Institute of Biomembranes and Bioenergetics, National Research Council, Via Amendola 165/A, Bari, 70126, Italy.
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35
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RCC2 is a novel p53 target in suppressing metastasis. Oncogene 2017; 37:8-17. [PMID: 28869598 PMCID: PMC5759027 DOI: 10.1038/onc.2017.306] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 07/14/2017] [Accepted: 07/20/2017] [Indexed: 12/17/2022]
Abstract
RCC2 (also known as TD60) is a highly conserved protein involved in prognosis in colorectal cancer. However, its relationship with tumor development is less understood. Here we demonstrate a signaling pathway defining regulation of RCC2 and its functions in tumor progression. We report that p53 is a transcriptional regulator of RCC2 that acts through its binding to a palindromic motif in the RCC2 promoter. RCC2 physically interacts and deactivates a small GTPase Rac1 that is known to be involved in metastasis. We solved a high-resolution crystal structure of RCC2 and revealed one RCC1-like domain with a unique β-hairpin that is requisite for RCC2 interaction with Rac1. p53 or RCC2 deficiency leads to activation of Rac1 and deterioration of extracellular matrix sensing (haptotaxis) of surface-bound gradients. Ectopic expression of RCC2 restores directional migration in p53-null cells. Our results demonstrate that p53 and RCC2 signaling is important for regulation of cell migration and suppression of metastasis. We propose that the p53/RCC2/Rac1 axis is a potential target for cancer therapy.
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36
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Liu K, Xing R, Jian Y, Gao Z, Ma X, Sun X, Li Y, Xu M, Wang X, Jing Y, Guo W, Yang C. WDR91 is a Rab7 effector required for neuronal development. J Cell Biol 2017; 216:3307-3321. [PMID: 28860274 PMCID: PMC5626554 DOI: 10.1083/jcb.201705151] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/03/2017] [Accepted: 07/12/2017] [Indexed: 12/22/2022] Open
Abstract
Early-to-late endosome conversion involves switching of early endosomes Rab5 and PtdIns3P to late endosomes Rab7 and PtdIns(3,5)P2. Liu et al. identify WDR91 as a Rab7 effector that couples Rab switching with PtdIns3P down-regulation on endosomes and show that WDR91 is essential for neuronal development. Early-to-late endosome conversion, which is essential for delivery of endosomal cargoes to lysosomes, requires switching of early endosome–specific Rab5 and PtdIns3P to late endosome–specific Rab7 and PtdIns(3,5)P2. In this study, we identify the WD40-repeat protein WDR91 as a Rab7 effector that couples Rab switching with PtdIns3P down-regulation on endosomes. Loss of WDR91 greatly increases endosomal PtdIns3P levels, arresting endosomes at an intermediate stage and blocking endosomal–lysosomal trafficking. WDR91 is recruited to endosomes by interacting with active guanosine triphosophate–Rab7 and inhibits Rab7-associated phosphatidylinositol 3-kinase activity. In mice, global Wdr91 knockout causes neonatal death, whereas brain-specific Wdr91 inactivation impairs brain development and causes postnatal death. Mouse neurons lacking Wdr91 accumulate giant intermediate endosomes and exhibit reduced neurite length and complexity. These phenotypes are rescued by WDR91 but not WDR91 mutants that cannot interact with Rab7. Thus, WDR91 serves as a Rab7 effector that is essential for neuronal development by facilitating endosome conversion in the endosome–lysosome pathway.
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Affiliation(s)
- Kai Liu
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Natural Resource Conservation and Utilization in Yunnan and Center for Life Science, School of Life Sciences, Yunnan University, Kunming, China
| | - Ruxiao Xing
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Youli Jian
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Zhiyang Gao
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xinli Ma
- Graduate University of Chinese Academy of Sciences, Beijing, China.,Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Xiaojuan Sun
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yang Li
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Meng Xu
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xin Wang
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Natural Resource Conservation and Utilization in Yunnan and Center for Life Science, School of Life Sciences, Yunnan University, Kunming, China
| | - Yudong Jing
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Weixiang Guo
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Chonglin Yang
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China .,State Key Laboratory of Natural Resource Conservation and Utilization in Yunnan and Center for Life Science, School of Life Sciences, Yunnan University, Kunming, China
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37
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Koyama M, Sasaki T, Sasaki N, Matsuura Y. Crystal structure of human WBSCR16, an RCC1-like protein in mitochondria. Protein Sci 2017; 26:1870-1877. [PMID: 28608466 DOI: 10.1002/pro.3210] [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: 04/27/2017] [Revised: 06/05/2017] [Accepted: 06/05/2017] [Indexed: 11/09/2022]
Abstract
WBSCR16 (Williams-Beuren Syndrome Chromosomal Region 16) gene is located in a large deletion region of Williams-Beuren syndrome (WBS), which is a neurodevelopmental disorder. Although the relationship between WBSCR16 and WBS remains unclear, it has been reported that WBSCR16 is a member of a functional module that regulates mitochondrial 16S rRNA abundance and intra-mitochondrial translation. WBSCR16 has RCC1 (Regulator of Chromosome Condensation 1)-like amino acid sequence repeats but the function of WBSCR16 appears to be different from that of other RCC1 superfamily members. Here, we demonstrate that WBSCR16 localizes to mitochondria in HeLa cells, and report the crystal structure of WBSCR16 determined to 2.0 Å resolution using multi-wavelength anomalous diffraction. WBSCR16 adopts the seven-bladed β-propeller fold characteristic of RCC1-like proteins. A comparison of the WBSCR16 structure with that of RCC1 and other RCC1-like proteins reveals that, although many of the residues buried in the core of the β-propeller are highly conserved, the surface residues are poorly conserved and conformationally divergent.
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Affiliation(s)
- Masako Koyama
- Division of Biological Science, Nagoya University, Furo-cho, Chikusa-ku, Japan
| | - Taeko Sasaki
- Division of Biological Science, Nagoya University, Furo-cho, Chikusa-ku, Japan
| | - Narie Sasaki
- Division of Biological Science, Nagoya University, Furo-cho, Chikusa-ku, Japan
| | - Yoshiyuki Matsuura
- Division of Biological Science, Nagoya University, Furo-cho, Chikusa-ku, Japan.,Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Japan
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38
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Timing and Reset Mechanism of GTP Hydrolysis-Driven Conformational Changes of Atlastin. Structure 2017; 25:997-1010.e4. [PMID: 28602821 DOI: 10.1016/j.str.2017.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/12/2017] [Accepted: 05/10/2017] [Indexed: 01/09/2023]
Abstract
The endoplasmic reticulum (ER) forms a branched, dynamic membrane tubule network that is vital for cellular function. Branching arises from membrane fusion facilitated by the GTPase atlastin (ATL). Many metazoan genomes encode for three ATL isoforms that appear to fulfill partially redundant function despite differences in their intrinsic GTPase activity and localization within the ER; however, the underlying mechanistic differences between the isoforms are poorly understood. Here, we identify discrete temporal steps in the catalytic cycle for the two most dissimilar isoforms, ATL1 and ATL3, revealing an overall conserved progression of molecular events from nucleotide binding and hydrolysis to ATL dimerization and phosphate release. A crystal structure of ATL3 suggests a mechanism for the displacement of the catalytic Mg2+ ion following guanosine triphosphate (GTP) hydrolysis. Together, the data extend the mechanistic framework for how GTP hydrolysis drives conformational changes in ATL and how the cycle is reset for subsequent rounds of catalysis.
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39
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Deschamps T, Bazot Q, Leske DM, MacLeod R, Mompelat D, Tafforeau L, Lotteau V, Maréchal V, Baillie GS, Gruffat H, Wilson JB, Manet E. Epstein-Barr virus nuclear antigen 1 interacts with regulator of chromosome condensation 1 dynamically throughout the cell cycle. J Gen Virol 2017; 98:251-265. [PMID: 28284242 DOI: 10.1099/jgv.0.000681] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) is a sequence-specific DNA-binding protein that plays an essential role in viral episome replication and segregation, by recruiting the cellular complex of DNA replication onto the origin (oriP) and by tethering the viral DNA onto the mitotic chromosomes. Whereas the mechanisms of viral DNA replication are well documented, those involved in tethering EBNA1 to the cellular chromatin are far from being understood. Here, we have identified regulator of chromosome condensation 1 (RCC1) as a novel cellular partner for EBNA1. RCC1 is the major nuclear guanine nucleotide exchange factor for the small GTPase Ran enzyme. RCC1, associated with chromatin, is involved in the formation of RanGTP gradients critical for nucleo-cytoplasmic transport, mitotic spindle formation and nuclear envelope reassembly following mitosis. Using several approaches, we have demonstrated a direct interaction between these two proteins and found that the EBNA1 domains responsible for EBNA1 tethering to the mitotic chromosomes are also involved in the interaction with RCC1. The use of an EBNA1 peptide array confirmed the interaction of RCC1 with these regions and also the importance of the N-terminal region of RCC1 in this interaction. Finally, using confocal microscopy and Förster resonance energy transfer analysis to follow the dynamics of interaction between the two proteins throughout the cell cycle, we have demonstrated that EBNA1 and RCC1 closely associate on the chromosomes during metaphase, suggesting an essential role for the interaction during this phase, perhaps in tethering EBNA1 to mitotic chromosomes.
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Affiliation(s)
- Thibaut Deschamps
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon 69364, France.,CNRS, UMR5308, Lyon 69364, France.,CIRI, International Center for Infectiology Research, Oncogenic Herpesviruses Team, Université de Lyon, Lyon 69364, France.,Ecole Normale Supérieure de Lyon, Lyon 69364, France.,INSERM, U1111, Lyon 69364, France
| | - Quentin Bazot
- Ecole Normale Supérieure de Lyon, Lyon 69364, France.,CNRS, UMR5308, Lyon 69364, France.,Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon 69364, France.,Present address: Section of Virology, Department of Medicine, Imperial College London, St Mary's Campus, London, UK.,CIRI, International Center for Infectiology Research, Oncogenic Herpesviruses Team, Université de Lyon, Lyon 69364, France.,INSERM, U1111, Lyon 69364, France
| | - Derek M Leske
- Present address: University of Oxford, Ludwig Institute for Cancer Research, Oxford, UK.,College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Ruth MacLeod
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Dimitri Mompelat
- Present address: University Joseph Fourier, Pathogenesis and Lentiviral Vaccination Laboratory, Grenoble, France.,INSERM, U1111, Lyon 69364, France.,Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon 69364, France.,Ecole Normale Supérieure de Lyon, Lyon 69364, France.,CIRI, International Center for Infectiology Research, Oncogenic Herpesviruses Team, Université de Lyon, Lyon 69364, France.,CNRS, UMR5308, Lyon 69364, France
| | - Lionel Tafforeau
- CIRI, International Center for Infectiology Research, Cell Biology of Viral Infections Team, Université de Lyon, Lyon 69364, France.,INSERM, U1111, Lyon 69364, France.,Present address: Cell Biology Lab, University of Mons, Mons, Belgium.,Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon 69364, France
| | - Vincent Lotteau
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon 69364, France.,Ecole Normale Supérieure de Lyon, Lyon 69364, France.,CNRS, UMR5308, Lyon 69364, France.,INSERM, U1111, Lyon 69364, France.,CIRI, International Center for Infectiology Research, Cell Biology of Viral Infections Team, Université de Lyon, Lyon 69364, France
| | - Vincent Maréchal
- UPMC Université Paris 6, Inserm, Centre d'Immunologie et des Maladies Infectieuses (Cimi-Paris), UMR 1135, ERL CNRS 8255, F-75013 Paris, France
| | - George S Baillie
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Henri Gruffat
- CNRS, UMR5308, Lyon 69364, France.,INSERM, U1111, Lyon 69364, France.,Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon 69364, France.,CIRI, International Center for Infectiology Research, Oncogenic Herpesviruses Team, Université de Lyon, Lyon 69364, France.,Ecole Normale Supérieure de Lyon, Lyon 69364, France
| | - Joanna B Wilson
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Evelyne Manet
- INSERM, U1111, Lyon 69364, France.,Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon 69364, France.,CIRI, International Center for Infectiology Research, Oncogenic Herpesviruses Team, Université de Lyon, Lyon 69364, France.,Ecole Normale Supérieure de Lyon, Lyon 69364, France.,CNRS, UMR5308, Lyon 69364, France
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40
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Dattilo V, D’Antona L, Talarico C, Capula M, Catalogna G, Iuliano R, Schenone S, Roperto S, Bianco C, Perrotti N, Amato R. SGK1 affects RAN/RANBP1/RANGAP1 via SP1 to play a critical role in pre-miRNA nuclear export: a new route of epigenomic regulation. Sci Rep 2017; 7:45361. [PMID: 28358001 PMCID: PMC5371792 DOI: 10.1038/srep45361] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 02/27/2017] [Indexed: 12/15/2022] Open
Abstract
The serum- and glucocorticoid-regulated kinase (SGK1) controls cell transformation and tumor progression. SGK1 affects mitotic stability by regulating the expression of RANBP1/RAN. Here, we demonstrate that SGK1 fluctuations indirectly modify the maturation of pre-miRNAs, by modulating the equilibrium of the RAN/RANBP1/RANGAP1 axis, the main regulator of nucleo-cytoplasmic transport. The levels of pre-miRNAs and mature miRNAs were assessed by qRT-PCR, in total extracts and after differential nuclear/cytoplasmic extraction. RANBP1 expression is the limiting step in the regulation of SGK1-SP1 dependent nuclear export. These results were validated in unrelated tumor models and primary human fibroblasts and corroborated in tumor-engrafted nude mice. The levels of pri-miRNAs, DROSHA, DICER and the compartmental distribution of XPO5 were documented. Experiments using RANGTP conformational antibodies confirmed that SGK1, through RANBP1, decreases the level of the GTP-bound state of RAN. This novel mechanism may play a role in the epigenomic regulation of cell physiology and fate.
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Affiliation(s)
- Vincenzo Dattilo
- University “Magna Graecia” of Catanzaro, Dept. of “Scienze della Salute”, Viale Europa Catanzaro, Italy
| | - Lucia D’Antona
- University “Magna Graecia” of Catanzaro, Dept. of “Scienze della Salute”, Viale Europa Catanzaro, Italy
| | - Cristina Talarico
- University “Magna Graecia” of Catanzaro, Dept. of “Scienze della Salute”, Viale Europa Catanzaro, Italy
| | - Mjriam Capula
- University “Magna Graecia” of Catanzaro, Dept. of “Scienze della Salute”, Viale Europa Catanzaro, Italy
| | - Giada Catalogna
- University “Magna Graecia” of Catanzaro, Dept. of “Scienze della Salute”, Viale Europa Catanzaro, Italy
| | - Rodolfo Iuliano
- University “Magna Graecia” of Catanzaro, Dept. of “Medicina Sperimentale e Clinica”, Viale Europa Catanzaro, Italy
| | - Silvia Schenone
- University of Genova, Dept of Farmacia, Viale Benedetto XV 3, Genova, Italy
| | - Sante Roperto
- University “Federico II” of Naple, Dept of Medicina Veterinaria e Produzioni Animali, Via Federico Delpino 1, Napoli, Italy.
| | - Cataldo Bianco
- University “Magna Graecia” of Catanzaro, Dept. of “Medicina Sperimentale e Clinica”, Viale Europa Catanzaro, Italy
| | - Nicola Perrotti
- University “Magna Graecia” of Catanzaro, Dept. of “Scienze della Salute”, Viale Europa Catanzaro, Italy
| | - Rosario Amato
- University “Magna Graecia” of Catanzaro, Dept. of “Scienze della Salute”, Viale Europa Catanzaro, Italy
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41
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Haggag YA, Matchett KB, Dakir EH, Buchanan P, Osman MA, Elgizawy SA, El-Tanani M, Faheem AM, McCarron PA. Nano-encapsulation of a novel anti-Ran-GTPase peptide for blockade of regulator of chromosome condensation 1 (RCC1) function in MDA-MB-231 breast cancer cells. Int J Pharm 2017; 521:40-53. [PMID: 28163220 DOI: 10.1016/j.ijpharm.2017.02.006] [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: 12/20/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 01/07/2023]
Abstract
Ran is a small ras-related GTPase and is highly expressed in aggressive breast carcinoma. Overexpression induces malignant transformation and drives metastatic growth. We have designed a novel series of anti-Ran-GTPase peptides, which prevents Ran hydrolysis and activation, and although they display effectiveness in silico, peptide activity is suboptimal in vitro due to reduced bioavailability and poor delivery. To overcome this drawback, we delivered an anti-Ran-GTPase peptide using encapsulation in PLGA-based nanoparticles (NP). Formulation variables within a double emulsion solvent evaporation technique were controlled to optimise physicochemical properties. NP were spherical and negatively charged with a mean diameter of 182-277nm. Peptide integrity and stability were maintained after encapsulation and release kinetics followed a sustained profile. We were interested in the relationship between cellular uptake and poly(ethylene glycol) (PEG) in the NP matrix, with results showing enhanced in vitro uptake with increasing PEG content. Peptide-loaded, pegylated (10% PEG)-PLGA NP induced significant cytotoxic and apoptotic effects in MDA-MB-231 breast cancer cells, with no evidence of similar effects in cells pulsed with free peptide. Western blot analysis showed that encapsulated peptide interfered with the proposed signal transduction pathway of the Ran gene. Our novel blockade peptide prevented Ran activation by blockage of regulator of chromosome condensation 1 (RCC1) following peptide release directly in the cytoplasm once endocytosis of the peptide-loaded nanoparticle has occurred. RCC1 blockage was effective only when a nanoparticulate delivery approach was adopted.
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Affiliation(s)
- Yusuf A Haggag
- School of Pharmacy and Pharmaceutical Sciences, Saad Centre for Pharmacy and Diabetes, Ulster University, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA, UK; Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Tanta, Tanta, Egypt
| | - Kyle B Matchett
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast BT9 7BL, UK
| | - El-Habib Dakir
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast BT9 7BL, UK; Institute of Cancer Therapeutics, University of Bradford, Bradford, UK
| | - Paul Buchanan
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Mohammed A Osman
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Tanta, Tanta, Egypt
| | - Sanaa A Elgizawy
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Tanta, Tanta, Egypt
| | - Mohamed El-Tanani
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast BT9 7BL, UK; Institute of Cancer Therapeutics, University of Bradford, Bradford, UK; IDT (Imhotep Diagnostics and Therapeutics), Europa Tool House, Springbank, Industrial Estate, Dunmurry, Northern Ireland, UK
| | - Ahmed M Faheem
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Tanta, Tanta, Egypt; Sunderland Pharmacy School, Department of Pharmacy, Health and Well Being, University of Sunderland, Sunderland SR1 3SD, UK
| | - Paul A McCarron
- School of Pharmacy and Pharmaceutical Sciences, Saad Centre for Pharmacy and Diabetes, Ulster University, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA, UK.
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42
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Kaufmann T, Kukolj E, Brachner A, Beltzung E, Bruno M, Kostrhon S, Opravil S, Hudecz O, Mechtler K, Warren G, Slade D. SIRT2 regulates nuclear envelope reassembly through ANKLE2 deacetylation. J Cell Sci 2016; 129:4607-4621. [PMID: 27875273 PMCID: PMC5201015 DOI: 10.1242/jcs.192633] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 11/09/2016] [Indexed: 12/18/2022] Open
Abstract
Sirtuin 2 (SIRT2) is an NAD-dependent deacetylase known to regulate microtubule dynamics and cell cycle progression. SIRT2 has also been implicated in the pathology of cancer, neurodegenerative diseases and progeria. Here, we show that SIRT2 depletion or overexpression causes nuclear envelope reassembly defects. We link this phenotype to the recently identified regulator of nuclear envelope reassembly ANKLE2. ANKLE2 acetylation at K302 and phosphorylation at S662 are dynamically regulated throughout the cell cycle by SIRT2 and are essential for normal nuclear envelope reassembly. The function of SIRT2 therefore extends beyond the regulation of microtubules to include the regulation of nuclear envelope dynamics.
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Affiliation(s)
- Tanja Kaufmann
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna 1030, Austria.,Department of Molecular Biotechnology, University of Applied Sciences FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Eva Kukolj
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna 1030, Austria
| | - Andreas Brachner
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna 1030, Austria
| | - Etienne Beltzung
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna 1030, Austria
| | - Melania Bruno
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna 1030, Austria
| | - Sebastian Kostrhon
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna 1030, Austria
| | - Susanne Opravil
- Institute of Molecular Pathology, Dr Bohr-Gasse 7, Vienna 1030, Austria
| | - Otto Hudecz
- Institute of Molecular Pathology, Dr Bohr-Gasse 7, Vienna 1030, Austria
| | - Karl Mechtler
- Institute of Molecular Pathology, Dr Bohr-Gasse 7, Vienna 1030, Austria
| | - Graham Warren
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna 1030, Austria
| | - Dea Slade
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Dr Bohr-Gasse 9, Vienna 1030, Austria
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43
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Abstract
Arl2 and Arl3 are Arf-like small GTP-binding proteins of the Arf subfamily of the Ras superfamily. Despite their structural similarity and sharing of many interacting partners, Arl2 and Arl3 have different biochemical properties and biological functions. Growing evidence suggest that Arl2 and Arl3 play a fundamental role as regulators of trafficking of lipid modified proteins between different compartments. Here we highlight the similarities and differences between these 2 homologous proteins and discuss the sorting mechanism of lipidated cargo into the ciliary compartment through the carriers PDE6δ and Unc119 and the release factors Arl2 and Arl3.
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Affiliation(s)
- Eyad K Fansa
- a Max Planck Institute of Molecular Physiology , Dortmund , Germany
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44
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A disappearing act performed by magnesium: the nucleotide exchange mechanism of Ran GTPase by quantum mechanics/molecular mechanics studies. Theor Chem Acc 2016. [DOI: 10.1007/s00214-016-1953-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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45
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Novel Coronin7 interactions with Cdc42 and N-WASP regulate actin organization and Golgi morphology. Sci Rep 2016; 6:25411. [PMID: 27143109 PMCID: PMC4855144 DOI: 10.1038/srep25411] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 04/18/2016] [Indexed: 12/28/2022] Open
Abstract
The contribution of the actin cytoskeleton to the unique architecture of the Golgi complex is manifold. An important player in this process is Coronin7 (CRN7), a Golgi-resident protein that stabilizes F-actin assembly at the trans-Golgi network (TGN) thereby facilitating anterograde trafficking. Here, we establish that CRN7-mediated association of F-actin with the Golgi apparatus is distinctly modulated via the small Rho GTPase Cdc42 and N-WASP. We identify N-WASP as a novel interaction partner of CRN7 and demonstrate that CRN7 restricts spurious F-actin reorganizations by repressing N-WASP 'hyperactivity' upon constitutive Cdc42 activation. Loss of CRN7 leads to increased cellular F-actin content and causes a concomitant disruption of the Golgi structure. CRN7 harbours a Cdc42- and Rac-interactive binding (CRIB) motif in its tandem β-propellers and binds selectively to GDP-bound Cdc42N17 mutant. We speculate that CRN7 can act as a cofactor for active Cdc42 generation. Mutation of CRIB motif residues that abrogate Cdc42 binding to CRN7 also fail to rescue the cellular defects in fibroblasts derived from CRN7 KO mice. Cdc42N17 overexpression partially rescued the KO phenotypes whereas N-WASP overexpression failed to do so. We conclude that CRN7 spatiotemporally influences F-actin organization and Golgi integrity in a Cdc42- and N-WASP-dependent manner.
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Sánchez-Tena S, Cubillos-Rojas M, Schneider T, Rosa JL. Functional and pathological relevance of HERC family proteins: a decade later. Cell Mol Life Sci 2016; 73:1955-68. [PMID: 26801221 PMCID: PMC11108380 DOI: 10.1007/s00018-016-2139-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 01/08/2016] [Accepted: 01/12/2016] [Indexed: 12/22/2022]
Abstract
The HERC gene family encodes proteins with two characteristic domains in their sequence: the HECT domain and the RCC1-like domain (RLD). In humans, the HERC family comprises six members that can be divided into two groups based on their molecular mass and domain structure. Whereas large HERCs (HERC1 and HERC2) contain one HECT and more than one RLD, small HERCs (HERC3-6) possess single HECT and RLD domains. Accumulating evidence shows the HERC family proteins to be key components of a wide range of cellular functions, including neurodevelopment, DNA damage repair, cell growth and immune response. Considering the significant recent advances made regarding HERC functionality, an updated review summarizing the progress is greatly needed at 10 years since the last HERC review. We provide an integrated view of HERC function and go into detail about its implications for several human diseases such as cancer and neurological disorders.
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Affiliation(s)
- Susana Sánchez-Tena
- Departament de Ciències Fisiològiques II, Campus de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Universitat de Barcelona, L'Hospitalet de Llobregat, 08907, Barcelona, Spain
| | - Monica Cubillos-Rojas
- Departament de Ciències Fisiològiques II, Campus de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Universitat de Barcelona, L'Hospitalet de Llobregat, 08907, Barcelona, Spain
| | - Taiane Schneider
- Departament de Ciències Fisiològiques II, Campus de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Universitat de Barcelona, L'Hospitalet de Llobregat, 08907, Barcelona, Spain
| | - Jose Luis Rosa
- Departament de Ciències Fisiològiques II, Campus de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Universitat de Barcelona, L'Hospitalet de Llobregat, 08907, Barcelona, Spain.
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Mechanisms of Nuclear Export in Cancer and Resistance to Chemotherapy. Cancers (Basel) 2016; 8:cancers8030035. [PMID: 26985906 PMCID: PMC4810119 DOI: 10.3390/cancers8030035] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 03/03/2016] [Accepted: 03/08/2016] [Indexed: 01/14/2023] Open
Abstract
Tumour suppressor proteins, such as p53, BRCA1, and ABC, play key roles in preventing the development of a malignant phenotype, but those that function as transcriptional regulators need to enter the nucleus in order to function. The export of proteins between the nucleus and cytoplasm is complex. It occurs through nuclear pores and exported proteins need a nuclear export signal (NES) to bind to nuclear exportin proteins, including CRM1 (Chromosomal Region Maintenance protein 1), and the energy for this process is provided by the RanGTP/RanGDP gradient. Due to the loss of DNA repair and cell cycle checkpoints, drug resistance is a major problem in cancer treatment, and often an initially successful treatment will fail due to the development of resistance. An important mechanism underlying resistance is nuclear export, and a number of strategies that can prevent nuclear export may reverse resistance. Examples include inhibitors of CRM1, antibodies to the nuclear export signal, and alteration of nuclear pore structure. Each of these are considered in this review.
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Schöppner P, Csaba G, Braun T, Daake M, Richter B, Lange OF, Zacharias M, Zimmer R, Haslbeck M. Regulatory Implications of Non-Trivial Splicing: Isoform 3 of Rab1A Shows Enhanced Basal Activity and Is Not Controlled by Accessory Proteins. J Mol Biol 2016; 428:1544-57. [PMID: 26953259 DOI: 10.1016/j.jmb.2016.02.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 02/19/2016] [Accepted: 02/24/2016] [Indexed: 01/04/2023]
Abstract
Alternative splicing often affects structured and highly conserved regions of proteins, generating so called non-trivial splicing variants of unknown structure and cellular function. The human small G-protein Rab1A is involved in the regulation of the vesicle transfer from the ER to Golgi. A conserved non-trivial splice variant lacks nearly 40% of the sequence of the native Rab1A, including most of the regulatory interaction sites. We show that this variant of Rab1A represents a stable and folded protein, which is still able to bind nucleotides and co-localizes with membranes. Nevertheless, it should be mentioned that compared to other wild-typeRabGTPases, the measured nucleotide binding affinities are dramatically reduced in the variant studied. Furthermore, the Rab1A variant forms hetero-dimers with wild-type Rab1A and its presence in the cell enhances the efficiency of alkaline phosphatase secretion. However, this variant shows no specificity for GXP nucleotides, a constantly enhanced GTP hydrolysis activity and is no longer controlled by GEF or GAP proteins, indicating a new regulatory mechanism for the Rab1A cycle via alternative non-trivial splicing.
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Affiliation(s)
- Patricia Schöppner
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Gergely Csaba
- Department of Informatics, Ludwig-Maximilians-Universität München, Amalienstr. 17, 80333 München, Germany
| | - Tatjana Braun
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Marina Daake
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Bettina Richter
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Oliver F Lange
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Martin Zacharias
- Physics Department, Technische Universität München, James-Franck-Strasse 1, 85747 Garching, Germany
| | - Ralf Zimmer
- Department of Informatics, Ludwig-Maximilians-Universität München, Amalienstr. 17, 80333 München, Germany.
| | - Martin Haslbeck
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany.
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Koch D, Rai A, Ali I, Bleimling N, Friese T, Brockmeyer A, Janning P, Goud B, Itzen A, Müller MP, Goody RS. A pull-down procedure for the identification of unknown GEFs for small GTPases. Small GTPases 2016; 7:93-106. [PMID: 26918858 PMCID: PMC4905258 DOI: 10.1080/21541248.2016.1156803] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Members of the family of small GTPases regulate a variety of important cellular functions. In order to accomplish this, tight temporal and spatial regulation is absolutely necessary. The two most important factors for this regulation are GTPase activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs), the latter being responsible for the activation of the GTPase downstream pathways at the correct location and time. Although a large number of exchange factors have been identified, it is likely that a similarly large number remains unidentified. We have therefore developed a procedure to specifically enrich GEF proteins from biological samples making use of the high affinity binding of GEFs to nucleotide-free GTPases. In order to verify the results of these pull-down experiments, we have additionally developed two simple validation procedures: An in vitro transcription/translation system coupled with a GEF activity assay and a yeast two-hybrid screen for detection of GEFs. Although the procedures were established and tested using the Rab protein Sec4, the similar basic principle of action of all nucleotide exchange factors will allow the method to be used for identification of unknown GEFs of small GTPases in general.
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Affiliation(s)
- Daniel Koch
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Amrita Rai
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Imtiaz Ali
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Nathalie Bleimling
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Timon Friese
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Andreas Brockmeyer
- b Department of Chemical Biology , Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Petra Janning
- b Department of Chemical Biology , Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Bruno Goud
- c Institut Curie, PSL Research University, CNRS UMR 144 , Paris , France
| | - Aymelt Itzen
- d Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München , Garching , Germany
| | - Matthias P Müller
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Roger S Goody
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
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Binkert M, Crocco CD, Ekundayo B, Lau K, Raffelberg S, Tilbrook K, Yin R, Chappuis R, Schalch T, Ulm R. Revisiting chromatin binding of the Arabidopsis UV-B photoreceptor UVR8. BMC PLANT BIOLOGY 2016; 16:42. [PMID: 26864020 PMCID: PMC4750278 DOI: 10.1186/s12870-016-0732-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/06/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND Plants perceive UV-B through the UV RESISTANCE LOCUS 8 (UVR8) photoreceptor and UVR8 activation leads to changes in gene expression such as those associated with UV-B acclimation and stress tolerance. Albeit functionally unrelated, UVR8 shows some homology with RCC1 (Regulator of Chromatin Condensation 1) proteins from non-plant organisms at the sequence level. These proteins act as guanine nucleotide exchange factors for Ran GTPases and bind chromatin via histones. Subsequent to the revelation of this sequence homology, evidence was presented showing that UVR8 activity involves interaction with chromatin at the loci of some target genes through histone binding. This suggested a UVR8 mode-of-action intimately and directly linked with gene transcription. However, several aspects of UVR8 chromatin association remained undefined, namely the impact of UV-B on the process and how UVR8 chromatin association related to the transcription factor ELONGATED HYPOCOTYL 5 (HY5), which is important for UV-B signalling and has overlapping chromatin targets. Therefore, we have investigated UVR8 chromatin association in further detail. RESULTS Unlike the claims of previous studies, our chromatin immunoprecipitation (ChIP) experiments do not confirm UVR8 chromatin association. In contrast to human RCC1, recombinant UVR8 also does not bind nucleosomes in vitro. Moreover, fusion of a VP16 activation domain to UVR8 did not alter expression of proposed UVR8 target genes in transient gene expression assays. Finally, comparison of the Drosophila DmRCC1 and the Arabidopsis UVR8 crystal structures revealed that critical histone- and DNA-interaction residues apparent in DmRCC1 are not conserved in UVR8. CONCLUSION This has led us to conclude that the cellular activity of UVR8 likely does not involve its specific binding to chromatin at target genes.
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Affiliation(s)
- Melanie Binkert
- Department of Botany and Plant Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
| | - Carlos D Crocco
- Department of Botany and Plant Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
| | - Babatunde Ekundayo
- Department of Molecular Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
| | - Kelvin Lau
- Department of Botany and Plant Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
| | - Sarah Raffelberg
- Department of Botany and Plant Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
| | - Kimberley Tilbrook
- Department of Botany and Plant Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
- Present Address: CSIRO Agriculture, Canberra, Australia.
| | - Ruohe Yin
- Department of Botany and Plant Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
| | - Richard Chappuis
- Department of Botany and Plant Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
| | - Thomas Schalch
- Department of Molecular Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
- Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, CH-1211, Geneva 4, Switzerland.
| | - Roman Ulm
- Department of Botany and Plant Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, CH-1211, Geneva 4, Switzerland.
- Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, CH-1211, Geneva 4, Switzerland.
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