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Hu C, Deng B, Fang W, Guo B, Chen P, Lu C, Dong Z, Pan M. Transgenic overexpression of bmo-miR-6498-5p increases resistance to Nosema bombycis in the silkworm, Bombyx mori. Appl Environ Microbiol 2024:e0027024. [PMID: 39240120 DOI: 10.1128/aem.00270-24] [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: 03/12/2024] [Accepted: 06/23/2024] [Indexed: 09/07/2024] Open
Abstract
Microsporidia are unfriendly microorganisms, and their infections cause considerable damage to economically or environmentally important insects like silkworms and honeybees. Thus, the identification of measures to improve host resistance to microsporidia infections is critically needed. Here, an overexpressed miR-6498-5p transgenic silkworm line was constructed. Importantly, the survival rates and median lethal doses of the transgenic line were clearly higher after infection with Nosema bombycis. H&E staining and RT-qPCR analyses revealed an inhibitory effect on the proliferation of N. bombycis in the transgenic larvae. Metabolomics analysis further revealed the presence of 56 differential metabolites between the two lines. KEGG analysis of these 56 metabolites found that they were involved in various amino acid and vitamin metabolism pathways. Notably, VB6 metabolism was enriched among the metabolites, and the pathway was well known for its involvement in the synthesis, interconversion, and degradation of amino acids. These suggest that miR-6498-5p modifies parasitic environments to inhibit the proliferation of N. bombycis by affecting the host amino acid metabolism. These results demonstrate the potential of microRNAs as biomolecules that can promote resistance to microsporidia and provide new insights and a new approach to generate microsporidia-resistant biological materials.IMPORTANCEMicrosporidia have an extremely wide host range and are capable of infecting a wide variety of insects and vertebrates, including humans, and their lethality to multiple species often poses significant environmental management challenge. Here, we successfully constructed a microsporidium-resistant line in the silkworm, based on the overexpression of miR-6498-5p. Our results strongly support the hypothesis that miR-6498-5p efficiently suppresses the proliferation of Nosema bombycis by regulating the host VB6 metabolism, a key pathway for enzymes involved in amino acid transport and protein metabolism. Our study provides new insights for understanding host anti-pathogen defenses toward microsporidia.
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Affiliation(s)
- Congwu Hu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- School of Chemical Engineering, Sichuan University of Science & Engineering, Zigong, Sichuan, China
| | - Boyuan Deng
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Wenxuan Fang
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Bingyu Guo
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Peng Chen
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing, China
| | - Cheng Lu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing, China
| | - Zhanqi Dong
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing, China
| | - Minhui Pan
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing, China
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2
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Bragulat-Teixidor H, Ishihara K, Szücs GM, Otsuka S. The endoplasmic reticulum connects to the nucleus by constricted junctions that mature after mitosis. EMBO Rep 2024; 25:3137-3159. [PMID: 38877171 PMCID: PMC11239909 DOI: 10.1038/s44319-024-00175-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 05/27/2024] [Accepted: 06/03/2024] [Indexed: 06/16/2024] Open
Abstract
Junctions between the endoplasmic reticulum (ER) and the outer membrane of the nuclear envelope (NE) physically connect both organelles. These ER-NE junctions are essential for supplying the NE with lipids and proteins synthesized in the ER. However, little is known about the structure of these ER-NE junctions. Here, we systematically study the ultrastructure of ER-NE junctions in cryo-fixed mammalian cells staged in anaphase, telophase, and interphase by correlating live cell imaging with three-dimensional electron microscopy. Our results show that ER-NE junctions in interphase cells have a pronounced hourglass shape with a constricted neck of 7-20 nm width. This morphology is significantly distinct from that of junctions within the ER network, and their morphology emerges as early as telophase. The highly constricted ER-NE junctions are seen in several mammalian cell types, but not in budding yeast. We speculate that the unique and highly constricted ER-NE junctions are regulated via novel mechanisms that contribute to ER-to-NE lipid and protein traffic in higher eukaryotes.
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Affiliation(s)
- Helena Bragulat-Teixidor
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria.
- Medical University of Vienna, Max Perutz Labs, Vienna, Austria.
- Vienna BioCenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria.
| | - Keisuke Ishihara
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gréta Martina Szücs
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Max Perutz Labs, Vienna, Austria
| | - Shotaro Otsuka
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria.
- Medical University of Vienna, Max Perutz Labs, Vienna, Austria.
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3
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Feng Z, Liu S, Su M, Song C, Lin C, Zhao F, Li Y, Zeng X, Zhu Y, Hou Y, Ren C, Zhang H, Yi P, Ji Y, Wang C, Li H, Ma M, Luo L, Li L. TANGO6 regulates cell proliferation via COPI vesicle-mediated RPB2 nuclear entry. Nat Commun 2024; 15:2371. [PMID: 38490996 PMCID: PMC10943085 DOI: 10.1038/s41467-024-46720-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 03/01/2024] [Indexed: 03/18/2024] Open
Abstract
Coat protein complex I (COPI) vesicles mediate the retrograde transfer of cargo between Golgi cisternae and from the Golgi to the endoplasmic reticulum (ER). However, their roles in the cell cycle and proliferation are unclear. This study shows that TANGO6 associates with COPI vesicles via two transmembrane domains. The TANGO6 N- and C-terminal cytoplasmic fragments capture RNA polymerase II subunit B (RPB) 2 in the cis-Golgi during the G1 phase. COPI-docked TANGO6 carries RPB2 to the ER and then to the nucleus. Functional disruption of TANGO6 hinders the nuclear entry of RPB2, which accumulates in the cytoplasm, causing cell cycle arrest in the G1 phase. The conditional depletion or overexpression of TANGO6 in mouse hematopoietic stem cells results in compromised or expanded hematopoiesis. Our study results demonstrate that COPI vesicle-associated TANGO6 plays a role in the regulation of cell cycle progression by directing the nuclear transfer of RPB2, making it a potential target for promoting or arresting cell expansion.
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Affiliation(s)
- Zhi Feng
- Research center of Stem cells and Ageing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, PR China
| | - Shengnan Liu
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University, Chongqing, 400715, PR China
| | - Ming Su
- Research center of Stem cells and Ageing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, PR China
| | - Chunyu Song
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University, Chongqing, 400715, PR China
| | - Chenyu Lin
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University, Chongqing, 400715, PR China
| | - Fangying Zhao
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University, Chongqing, 400715, PR China
| | - Yang Li
- Research center of Stem cells and Ageing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, PR China
| | - Xianyan Zeng
- Institute of Life Sciences, Laboratory of Developmental Biology, Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing, 400016, PR China
| | - Yong Zhu
- Institute of Life Sciences, Laboratory of Developmental Biology, Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing, 400016, PR China
| | - Yu Hou
- Institute of Life Sciences, Laboratory of Developmental Biology, Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing, 400016, PR China
| | - Chunguang Ren
- Institute of Life Sciences, Laboratory of Developmental Biology, Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing, 400016, PR China
| | - Huan Zhang
- Institute of Life Sciences, Laboratory of Developmental Biology, Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing, 400016, PR China
| | - Ping Yi
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, 401120, PR China
| | - Yong Ji
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine; Key Laboratory of Targeted Intervention of Cardiovascular Disease; Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, 211166, PR China
- National Key Laboratory of Frigid Zone Cardiovascular Diseases (NKLFZCD), Harbin Medical University, Harbin, 150076, Heilongjiang, PR China
| | - Chao Wang
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, PR China
| | - Hongtao Li
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University, Chongqing, 400715, PR China
| | - Ming Ma
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University, Chongqing, 400715, PR China
| | - Lingfei Luo
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University, Chongqing, 400715, PR China.
| | - Li Li
- Research center of Stem cells and Ageing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, PR China.
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4
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He J, Ding Y, Lin H, Liu X, Chen X, Shen W, Zhou S, Feng C, Wang M, Xia J, He N. Differential genome-wide associated variants and enriched pathways of ECG parameters among people with versus without HIV. AIDS 2023; 37:1871-1882. [PMID: 37418550 PMCID: PMC10481915 DOI: 10.1097/qad.0000000000003647] [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: 03/02/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/09/2023]
Abstract
OBJECTIVES People with HIV (PWH) are more likely to develop ECG abnormalities. Substantial evidence exists for genetic contribution to ECG parameters among general population. However, whether and how would host genome associate with ECG parameters among PWH is unclear. Our research aims to analyze and compare genetic variants, mapped genes, and enriched pathways of ECG parameters among PWH and HIV-negative controls. DESIGN A cross-sectional study. METHOD We performed a large original genome-wide association study (GWAS) of ECG parameters among PWH ( n = 1730) and HIV-negative controls ( n = 3746). Genome-wide interaction analyses were also conducted. RESULTS A total of 18 novel variants were detected among PWH, six for PR interval including rs76345397 at ATL2 , 11 for QRS duration including rs10483994 at KCNK10 and rs2478830 at JCAD , and one for QTc interval (rs9815364). Among HIV-negative controls, we identified variants located at previously reported ECG-related genes ( SCN5A , CNOT1 ). Genetic variants had a significant interaction with HIV infection ( P < 5 × 10 -8 ), implying that HIV infection and host genome might jointly influence ECG parameters. Mapped genes for PR interval and QRS duration among PWH were enriched in the biological process of viral genome replication and host response to virus, respectively, whereas enriched pathways for PR interval among HIV-negative controls were in the cellular component of voltage-gated sodium channel complex. CONCLUSION The present GWAS indicated a distinctive impact of host genome on quantitative ECG parameters among PWH. Different from HIV-negative controls, host genome might influence the cardiac electrical activity by interfering with HIV viral infection, production, and latency among PWH.
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Affiliation(s)
- Jiayu He
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Yi-Wu Research Institute
- Shanghai Institute of Infectious Diseases and Biosecurity, Fudan University, Shanghai
| | - Yingying Ding
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Yi-Wu Research Institute
| | - Haijiang Lin
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Taizhou City Center for Disease Control and Prevention, Zhejiang Province, China
| | - Xing Liu
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Yi-Wu Research Institute
| | - Xiaoxiao Chen
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Taizhou City Center for Disease Control and Prevention, Zhejiang Province, China
| | - Weiwei Shen
- Taizhou City Center for Disease Control and Prevention, Zhejiang Province, China
| | - Sujuan Zhou
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Yi-Wu Research Institute
- Shanghai Institute of Infectious Diseases and Biosecurity, Fudan University, Shanghai
| | - Cheng Feng
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Yi-Wu Research Institute
| | - Miaochen Wang
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Yi-Wu Research Institute
| | - Jingjing Xia
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Yi-Wu Research Institute
| | - Na He
- Department of Epidemiology, School of Public Health, and Key Laboratory of Public Health Safety of Ministry of Education
- Yi-Wu Research Institute
- Shanghai Institute of Infectious Diseases and Biosecurity, Fudan University, Shanghai
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5
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Bryce S, Stolzer M, Crosby D, Yang R, Durand D, Lee TH. Human atlastin-3 is a constitutive ER membrane fusion catalyst. J Cell Biol 2023; 222:e202211021. [PMID: 37102997 PMCID: PMC10140384 DOI: 10.1083/jcb.202211021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 02/28/2023] [Accepted: 04/04/2023] [Indexed: 04/28/2023] Open
Abstract
Homotypic membrane fusion catalyzed by the atlastin (ATL) GTPase sustains the branched endoplasmic reticulum (ER) network in metazoans. Our recent discovery that two of the three human ATL paralogs (ATL1/2) are C-terminally autoinhibited implied that relief of autoinhibition would be integral to the ATL fusion mechanism. An alternative hypothesis is that the third paralog ATL3 promotes constitutive ER fusion with relief of ATL1/2 autoinhibition used conditionally. However, published studies suggest ATL3 is a weak fusogen at best. Contrary to expectations, we demonstrate here that purified human ATL3 catalyzes efficient membrane fusion in vitro and is sufficient to sustain the ER network in triple knockout cells. Strikingly, ATL3 lacks any detectable C-terminal autoinhibition, like the invertebrate Drosophila ATL ortholog. Phylogenetic analysis of ATL C-termini indicates that C-terminal autoinhibition is a recent evolutionary innovation. We suggest that ATL3 is a constitutive ER fusion catalyst and that ATL1/2 autoinhibition likely evolved in vertebrates as a means of upregulating ER fusion activity on demand.
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Affiliation(s)
- Samantha Bryce
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Maureen Stolzer
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Daniel Crosby
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Ruijin Yang
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Dannie Durand
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Tina H. Lee
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
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6
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Jang E, Moon Y, Yoon SY, Diaz JAR, Lee M, Ko N, Park J, Eom SH, Lee C, Jun Y. Human atlastins are sufficient to drive the fusion of liposomes with a physiological lipid composition. J Cell Biol 2023; 222:e202109090. [PMID: 36757370 PMCID: PMC9949273 DOI: 10.1083/jcb.202109090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/20/2022] [Accepted: 01/17/2023] [Indexed: 02/10/2023] Open
Abstract
The dynamin-like GTPase atlastin is believed to be the minimal machinery required for homotypic endoplasmic reticulum (ER) membrane fusion, mainly because Drosophila atlastin is sufficient to drive liposome fusion. However, it remains unclear whether mammalian atlastins, including the three human atlastins, are sufficient to induce liposome fusion, raising doubts about their major roles in mammalian cells. Here, we show that all human atlastins are sufficient to induce fusion when reconstituted into liposomes with a lipid composition mimicking that of the ER. Although the fusogenic activity of ATL1, which is predominantly expressed in neuronal cells, was weaker than that of ATL2 or ATL3, the addition of M1-spastin, a neuron-specific factor, markedly increased ATL1-mediated liposome fusion. Although we observed efficient fusion between ER microsomes isolated from cultured, non-neuronal cells that predominantly express ATL2-1, an autoinhibited isoform of ATL2, ATL2-1 failed to support liposome fusion by itself as reported previously, indicating that cellular factors enable ATL2-1 to mediate ER fusion in vivo.
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Affiliation(s)
- Eunhong Jang
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Yeojin Moon
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - So Young Yoon
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Joyce Anne R. Diaz
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Miriam Lee
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Naho Ko
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Jongseo Park
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Soo Hyun Eom
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Changwook Lee
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Youngsoo Jun
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
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7
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Nuclear envelope assembly and dynamics during development. Semin Cell Dev Biol 2023; 133:96-106. [PMID: 35249812 DOI: 10.1016/j.semcdb.2022.02.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 01/22/2023]
Abstract
The nuclear envelope (NE) protects but also organizes the eukaryotic genome. In this review we will discuss recent literature on how the NE disassembles and reassembles, how it varies in surface area and protein composition and how this translates into chromatin organization and gene expression in the context of animal development.
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8
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LaJoie D, Turkmen AM, Mackay DR, Jensen CC, Aksenova V, Niwa M, Dasso M, Ullman KS. A role for Nup153 in nuclear assembly reveals differential requirements for targeting of nuclear envelope constituents. Mol Biol Cell 2022; 33:ar117. [PMID: 36044344 PMCID: PMC9634965 DOI: 10.1091/mbc.e22-05-0189] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 01/18/2023] Open
Abstract
Assembly of the nucleus following mitosis requires rapid and coordinate recruitment of diverse constituents to the inner nuclear membrane. We have identified an unexpected role for the nucleoporin Nup153 in promoting the continued addition of a subset of nuclear envelope (NE) proteins during initial expansion of nascent nuclei. Specifically, disrupting the function of Nup153 interferes with ongoing addition of B-type lamins, lamin B receptor, and SUN1 early in telophase, after the NE has initially enclosed chromatin. In contrast, effects on lamin A and SUN2 were minimal, pointing to differential requirements for the ongoing targeting of NE proteins. Further, distinct mistargeting phenotypes arose among the proteins that require Nup153 for NE targeting. Thus, disrupting the function of Nup153 in nuclear formation reveals several previously undescribed features important for establishing nuclear architecture: 1) a role for a nuclear basket constituent in ongoing recruitment of nuclear envelope components, 2) two functionally separable phases of NE formation in mammalian cells, and 3) distinct requirements of individual NE residents for continued targeting during the expansion phase of NE reformation.
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Affiliation(s)
- Dollie LaJoie
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112
| | - Ayse M. Turkmen
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112
| | - Douglas R. Mackay
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112
| | - Christopher C. Jensen
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112
| | - Vasilisa Aksenova
- Division of Molecular and Cellular Biology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Maho Niwa
- Division of Biological Sciences, Section of Molecular Biology, University of California, San Diego, La Jolla, CA 92093
| | - Mary Dasso
- Division of Molecular and Cellular Biology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Katharine S. Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112
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9
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Hahn L, Carvalho P. Making and breaking the inner nuclear membrane proteome. Curr Opin Cell Biol 2022; 78:102115. [PMID: 35870351 DOI: 10.1016/j.ceb.2022.102115] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 06/12/2022] [Accepted: 06/17/2022] [Indexed: 01/31/2023]
Abstract
The nuclear envelope (NE) is the defining feature of eukaryotic cells, separating the nucleus from the cytoplasm. It has a complex architecture consisting of two lipid bilayers that, despite being continuous between them and with the endoplasmic reticulum, have different protein compositions consistent with their distinct functions. In particular, the unique composition of the inner nuclear membrane (INM), facing the nucleoplasm and its underlying nuclear lamina, is critical for the organisation and function of nuclear processes, from cell fate to gene regulation and DNA repair. Mutations in INM proteins affecting this organisation are associated with muscular dystrophies and premature ageing syndromes highlighting the role of INM architecture in cell homeostasis. Here, we discuss recent progress in understanding how specific proteins concentrate at the INM, as well as the quality control mechanisms involved in remodelling and maintaining INM protein homeostasis.
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Affiliation(s)
- Lilli Hahn
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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10
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Anggrandariyanny PC, Kajiho H, Yamamoto Y, Sakisaka T. Lunapark ubiquitinates atlastin-2 for the tubular network formation of the endoplasmic reticulum. J Biochem 2022; 172:245-257. [PMID: 35894092 DOI: 10.1093/jb/mvac060] [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: 05/15/2022] [Accepted: 07/11/2022] [Indexed: 11/14/2022] Open
Abstract
Endoplasmic reticulum (ER) tubules are interconnected by three-way junctions, resulting in the formation of a tubular ER network. Lunapark (Lnp) localizes to and stabilizes the three-way junctions. The N-terminal cytoplasmic domain in Lnp has a ubiquitin ligase activity. However, the molecular mechanism of how the ubiquitin ligase activity of Lnp is involved in the formation of the tubular ER network remains unknown. In this study, we examined whether the ER membrane proteins responsible for the formation of the tubular ER network are ubiquitinated by Lnp. We found that atlastin-2 (ATL2), an isoform of the ATL family mediating the generation of the three-way junctions by connecting the ER tubules, is a novel substrate for ubiquitination by Lnp. The localization of Lnp at the three-way junctions is important for ubiquitination of ATL2. Lysine 56, 57, 282, and 302 are the potential ubiquitination sites by Lnp. Silencing ATL2 decreased the number of the three-way junctions, and the expression of the ATL2 mutant in which the lysine residues are substituted with arginine failed to rescue the decrease of the three-way junctions in the ATL2 knocked-down cells. These results suggest that Lnp ubiquitinates ATL2 at the three-way junctions for the proper tubular ER network formation.
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Affiliation(s)
- Putri Chynthia Anggrandariyanny
- Division of Membrane Dynamics, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
| | - Hiroaki Kajiho
- Division of Membrane Dynamics, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
| | - Yasunori Yamamoto
- Division of Membrane Dynamics, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
| | - Toshiaki Sakisaka
- Division of Membrane Dynamics, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
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11
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A role for endoplasmic reticulum dynamics in the cellular distribution of microtubules. Proc Natl Acad Sci U S A 2022; 119:e2104309119. [PMID: 35377783 PMCID: PMC9169640 DOI: 10.1073/pnas.2104309119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The endoplasmic reticulum (ER) and the microtubule (MT) cytoskeleton form a coextensive, dynamic system that pervades eukaryotic cells. The shape of the ER is generated by a set of evolutionarily conserved membrane proteins that are able to control ER morphology and dynamics independently of MTs. Here we uncover that the molecular machinery that determines ER network dynamics can influence the subcellular distribution of MTs. We show that active control of local ER tubule junction density by ER tethering and fusion is important for the spatial organization of the combined ER–MT system. Our work suggests that cells might alter ER junction dynamics to drive formation of MT bundles, which are important structures, e.g., in migrating cells or in neuronal axons. The dynamic distribution of the microtubule (MT) cytoskeleton is crucial for the shape, motility, and internal organization of eukaryotic cells. However, the basic principles that control the subcellular position of MTs in mammalian interphase cells remain largely unknown. Here we show by a combination of microscopy and computational modeling that the dynamics of the endoplasmic reticulum (ER) plays an important role in distributing MTs in the cell. Specifically, our physics-based model of the ER–MT system reveals that spatial inhomogeneity in the density of ER tubule junctions results in an overall contractile force that acts on MTs and influences their distribution. At steady state, cells rapidly compensate for local variability of ER junction density by dynamic formation, release, and movement of ER junctions across the ER. Perturbation of ER junction tethering and fusion by depleting the ER fusogens called atlastins disrupts the dynamics of junction equilibration, rendering the ER–MT system unstable and causing the formation of MT bundles. Our study points to a mechanical role of ER dynamics in cellular organization and suggests a mechanism by which cells might dynamically regulate MT distribution in, e.g., motile cells or in the formation and maintenance of neuronal axons.
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12
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Golchoubian B, Brunner A, Bragulat-Teixidor H, Neuner A, Akarlar BA, Ozlu N, Schlaitz AL. Reticulon-like REEP4 at the inner nuclear membrane promotes nuclear pore complex formation. J Cell Biol 2022; 221:212893. [PMID: 34874453 PMCID: PMC8656412 DOI: 10.1083/jcb.202101049] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 10/11/2021] [Accepted: 11/18/2021] [Indexed: 12/11/2022] Open
Abstract
Nuclear pore complexes (NPCs) are channels within the nuclear envelope that mediate nucleocytoplasmic transport. NPCs form within the closed nuclear envelope during interphase or assemble concomitantly with nuclear envelope reformation in late stages of mitosis. Both interphase and mitotic NPC biogenesis require coordination of protein complex assembly and membrane deformation. During early stages of mitotic NPC assembly, a seed for new NPCs is established on chromatin, yet the factors connecting the NPC seed to the membrane of the forming nuclear envelope are unknown. Here, we report that the reticulon homology domain protein REEP4 not only localizes to high-curvature membrane of the cytoplasmic endoplasmic reticulum but is also recruited to the inner nuclear membrane by the NPC biogenesis factor ELYS. This ELYS-recruited pool of REEP4 promotes NPC assembly and appears to be particularly important for NPC formation during mitosis. These findings suggest a role for REEP4 in coordinating nuclear envelope reformation with mitotic NPC biogenesis.
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Affiliation(s)
- Banafsheh Golchoubian
- Centre for Molecular Biology of Heidelberg University, Heidelberg, Germany.,Biochemistry Centre of Heidelberg University, Heidelberg, Germany
| | - Andreas Brunner
- Centre for Molecular Biology of Heidelberg University, Heidelberg, Germany
| | | | - Annett Neuner
- Centre for Molecular Biology of Heidelberg University, Heidelberg, Germany
| | - Busra A Akarlar
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Nurhan Ozlu
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Anne-Lore Schlaitz
- Centre for Molecular Biology of Heidelberg University, Heidelberg, Germany.,Biochemistry Centre of Heidelberg University, Heidelberg, Germany
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13
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Pawar S, Kutay U. The Diverse Cellular Functions of Inner Nuclear Membrane Proteins. Cold Spring Harb Perspect Biol 2021; 13:a040477. [PMID: 33753404 PMCID: PMC8411953 DOI: 10.1101/cshperspect.a040477] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nuclear compartment is delimited by a specialized expanded sheet of the endoplasmic reticulum (ER) known as the nuclear envelope (NE). Compared to the outer nuclear membrane and the contiguous peripheral ER, the inner nuclear membrane (INM) houses a unique set of transmembrane proteins that serve a staggering range of functions. Many of these functions reflect the exceptional position of INM proteins at the membrane-chromatin interface. Recent research revealed that numerous INM proteins perform crucial roles in chromatin organization, regulation of gene expression, genome stability, and mediation of signaling pathways into the nucleus. Other INM proteins establish mechanical links between chromatin and the cytoskeleton, help NE remodeling, or contribute to the surveillance of NE integrity and homeostasis. As INM proteins continue to gain prominence, we review these advancements and give an overview on the functional versatility of the INM proteome.
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Affiliation(s)
- Sumit Pawar
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ulrike Kutay
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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14
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Amaya C, Cameron CJF, Devarkar SC, Seager SJH, Gerstein MB, Xiong Y, Schlieker C. Nodal modulator (NOMO) is required to sustain endoplasmic reticulum morphology. J Biol Chem 2021; 297:100937. [PMID: 34224731 PMCID: PMC8327139 DOI: 10.1016/j.jbc.2021.100937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 06/24/2021] [Accepted: 07/01/2021] [Indexed: 12/03/2022] Open
Abstract
The endoplasmic reticulum (ER) is a membrane-bound organelle responsible for protein folding, lipid synthesis, and calcium homeostasis. Maintenance of ER structural integrity is crucial for proper function, but much remains to be learned about the molecular players involved. To identify proteins that support the structure of the ER, we performed a proteomic screen and identified nodal modulator (NOMO), a widely conserved type I transmembrane protein of unknown function, with three nearly identical orthologs specified in the human genome. We found that overexpression of NOMO1 imposes a sheet morphology on the ER, whereas depletion of NOMO1 and its orthologs causes a collapse of ER morphology concomitant with the formation of membrane-delineated holes in the ER network positive for the lysosomal marker lysosomal-associated protein 1. In addition, the levels of key players of autophagy including microtubule-associated protein light chain 3 and autophagy cargo receptor p62/sequestosome 1 strongly increase upon NOMO depletion. In vitro reconstitution of NOMO1 revealed a "beads on a string" structure likely representing consecutive immunoglobulin-like domains. Extending NOMO1 by insertion of additional immunoglobulin folds results in a correlative increase in the ER intermembrane distance. Based on these observations and a genetic epistasis analysis including the known ER-shaping proteins Atlastin2 and Climp63, we propose a role for NOMO1 in the functional network of ER-shaping proteins.
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Affiliation(s)
- Catherine Amaya
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Christopher J F Cameron
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Swapnil C Devarkar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Sebastian J H Seager
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Mark B Gerstein
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA; Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, USA; Department of Computer Science, Yale University, New Haven, Connecticut, USA; Department of Statistics and Data Science, Yale University, New Haven, Connecticut, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Christian Schlieker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA; Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut, USA.
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15
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Kutay U, Jühlen R, Antonin W. Mitotic disassembly and reassembly of nuclear pore complexes. Trends Cell Biol 2021; 31:1019-1033. [PMID: 34294532 DOI: 10.1016/j.tcb.2021.06.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 12/19/2022]
Abstract
Nuclear pore complexes (NPCs) are huge protein assemblies within the nuclear envelope (NE) that serve as selective gates for macromolecular transport between nucleus and cytoplasm. When higher eukaryotic cells prepare for division, they rapidly disintegrate NPCs during NE breakdown such that nuclear and cytoplasmic components mix to enable the formation of a cytoplasmic mitotic spindle. At the end of mitosis, reassembly of NPCs is coordinated with the establishment of the NE around decondensing chromatin. We review recent progress on mitotic NPC disassembly and reassembly, focusing on vertebrate cells. We highlight novel mechanistic insights into how NPCs are rapidly disintegrated into conveniently reusable building blocks, and put divergent models of (post-)mitotic NPC assembly into a spatial and temporal context.
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Affiliation(s)
- Ulrike Kutay
- Institute of Biochemistry, Department of Biology, Eidgenössische Technische Hochschule (ETH) Zurich, Otto-Stern-Weg 3, 8093 Zurich, Switzerland.
| | - Ramona Jühlen
- Institute of Biochemistry and Molecular Cell Biology, Medical School, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany
| | - Wolfram Antonin
- Institute of Biochemistry and Molecular Cell Biology, Medical School, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
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16
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Liu N, Zhao H, Zhao YG, Hu J, Zhang H. Atlastin 2/3 regulate ER targeting of the ULK1 complex to initiate autophagy. J Cell Biol 2021; 220:e202012091. [PMID: 33988678 PMCID: PMC8129792 DOI: 10.1083/jcb.202012091] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/22/2021] [Accepted: 04/19/2021] [Indexed: 01/31/2023] Open
Abstract
Dynamic targeting of the ULK1 complex to the ER is crucial for initiating autophagosome formation and for subsequent formation of ER-isolation membrane (IM; autophagosomal precursor) contact during IM expansion. Little is known about how the ULK1 complex, which comprises FIP200, ULK1, ATG13, and ATG101 and does not exist as a constitutively coassembled complex, is recruited and stabilized on the ER. Here, we demonstrate that the ER-localized transmembrane proteins Atlastin 2 and 3 (ATL2/3) contribute to recruitment and stabilization of ULK1 and ATG101 at the FIP200-ATG13-specified autophagosome formation sites on the ER. In ATL2/3 KO cells, formation of FIP200 and ATG13 puncta is unaffected, while targeting of ULK1 and ATG101 is severely impaired. Consequently, IM initiation is compromised and slowed. ATL2/3 directly interact with ULK1 and ATG13 and facilitate the ATG13-mediated recruitment/stabilization of ULK1 and ATG101. ATL2/3 also participate in forming ER-IM tethering complexes. Our study provides insights into the dynamic assembly of the ULK1 complex on the ER for autophagosome formation.
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Affiliation(s)
- Nan Liu
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People’s Republic of China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Hongyu Zhao
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Yan G. Zhao
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, People’s Republic of China
| | - Junjie Hu
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People’s Republic of China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Hong Zhang
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People’s Republic of China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
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17
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Behrendt L, Hoischen C, Kaether C. Disease-causing mutated ATLASTIN 3 is excluded from distal axons and reduces axonal autophagy. Neurobiol Dis 2021; 155:105400. [PMID: 34019998 DOI: 10.1016/j.nbd.2021.105400] [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: 01/07/2021] [Revised: 04/27/2021] [Accepted: 05/16/2021] [Indexed: 10/21/2022] Open
Abstract
Mutations in the ER-network forming GTPase atlastin3 (ATL3) can cause axon degeneration of sensory neurons by not fully understood mechanisms. We here show that the hereditary sensory and autonomous neuropathy (HSAN)-causing ATL3 Y192C or P338R are excluded from distal axons by a barrier at the axon initial segment (AIS). This barrier is selective for mutated ATL3, but not wildtype ATL3 or unrelated ER-membrane proteins. Actin-depolymerization partially restores the transport of ATL3 Y192C into distal axons. The results point to the existence of a selective diffusion barrier in the ER membrane at the AIS, analogous to the AIS-based barriers for plasma membrane and cytosolic proteins. Functionally, the absence of ATL3 at the distal axon reduces axonal autophagy and the ER network deformation in the soma causes a reduction in axonal lysosomes. Both could contribute to axonal degeneration and eventually to HSAN.
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Affiliation(s)
- Laura Behrendt
- Leibniz-Institut für Alternsforschung-Fritz-Lipmann-Institut, 07745 Jena, Germany
| | - Christian Hoischen
- Leibniz-Institut für Alternsforschung-Fritz-Lipmann-Institut, 07745 Jena, Germany
| | - Christoph Kaether
- Leibniz-Institut für Alternsforschung-Fritz-Lipmann-Institut, 07745 Jena, Germany.
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18
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Hüsler D, Steiner B, Welin A, Striednig B, Swart AL, Molle V, Hilbi H, Letourneur F. Dictyostelium lacking the single atlastin homolog Sey1 shows aberrant ER architecture, proteolytic processes and expansion of the Legionella-containing vacuole. Cell Microbiol 2021; 23:e13318. [PMID: 33583106 DOI: 10.1111/cmi.13318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 02/06/2023]
Abstract
Dictyostelium discoideum Sey1 is the single ortholog of mammalian atlastin 1-3 (ATL1-3), which are large homodimeric GTPases mediating homotypic fusion of endoplasmic reticulum (ER) tubules. In this study, we generated a D. discoideum mutant strain lacking the sey1 gene and found that amoebae deleted for sey1 are enlarged, but grow and develop similarly to the parental strain. The ∆sey1 mutant amoebae showed an altered ER architecture, and the tubular ER network was partially disrupted without any major consequences for other organelles or the architecture of the secretory and endocytic pathways. Macropinocytic and phagocytic functions were preserved; however, the mutant amoebae exhibited cumulative defects in lysosomal enzymes exocytosis, intracellular proteolysis, and cell motility, resulting in impaired growth on bacterial lawns. Moreover, ∆sey1 mutant cells showed a constitutive activation of the unfolded protein response pathway (UPR), but they still readily adapted to moderate levels of ER stress, while unable to cope with prolonged stress. In D. discoideum ∆sey1 the formation of the ER-associated compartment harbouring the bacterial pathogen Legionella pneumophila was also impaired. In the mutant amoebae, the ER was less efficiently recruited to the "Legionella-containing vacuole" (LCV), the expansion of the pathogen vacuole was inhibited at early stages of infection and intracellular bacterial growth was reduced. In summary, our study establishes a role of D. discoideum Sey1 in ER architecture, proteolysis, cell motility and intracellular replication of L. pneumophila.
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Affiliation(s)
- Dario Hüsler
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Bernhard Steiner
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Amanda Welin
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Bianca Striednig
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - A Leoni Swart
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Virginie Molle
- Laboratory of Pathogen Host Interactions, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - François Letourneur
- Laboratory of Pathogen Host Interactions, Université de Montpellier, CNRS, INSERM, Montpellier, France
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19
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Dong Z, Zheng N, Hu C, Huang X, Chen P, Wu Q, Deng B, Lu C, Pan M. Genetic bioengineering of overexpressed guanylate binding protein family BmAtlastin-n enhances silkworm resistance to Nosema bombycis. Int J Biol Macromol 2021; 172:223-230. [PMID: 33453252 DOI: 10.1016/j.ijbiomac.2021.01.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 12/25/2020] [Accepted: 01/04/2021] [Indexed: 11/15/2022]
Abstract
Microsporidia are obligate single-celled eukaryote parasites. Microsporidian infection can cause large economic losses to beneficial insects such as silkworms and honey bees. Identification of resistance biomacromolecules and breeding of transgenic lines resistant to the microsporidian Nosema bombycis are important for disease management. We previously used transcriptome analysis to identify a guanylate binding protein family BmAtlastin-n gene that was significantly upregulated after Nosema bombycis infection, and we determined that the molecule was highly expressed in resistance-related tissues such as the midgut, fat body and the epidermis. The transgenic silkworm line overexpressing BmAtlastin-n biomolecules had economic characters similar to those of non-transgenic lines. The transgenic OE-BmAtlastin-n lines had significantly improved survival after microspore infection. We used RT-PCR and H&E staining to show that the number of spores in the transgenic lines was significantly lower than in the control lines. In this study, we identified a BmAtlastin-n macromolecule with resistance to N. bombycis and developed a transgenic line. The results improved understanding of the GBP protein family and provided biomacromolecule material for the treatment and prevention of microsporidia.
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Affiliation(s)
- Zhanqi Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China
| | - Ning Zheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Congwu Hu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Xuhua Huang
- The General Extension Station of Sericulture Technology of Guangxi Zhuang Autonomous Region, Nanning 530007, China
| | - Peng Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China
| | - Qin Wu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Boyuan Deng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China.
| | - Minhui Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China.
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20
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Mou Y, Dong Y, Chen Z, Denton KR, Duff MO, Blackstone C, Zhang SC, Li XJ. Impaired lipid metabolism in astrocytes underlies degeneration of cortical projection neurons in hereditary spastic paraplegia. Acta Neuropathol Commun 2020; 8:214. [PMID: 33287888 PMCID: PMC7720406 DOI: 10.1186/s40478-020-01088-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 11/18/2020] [Indexed: 12/11/2022] Open
Abstract
Hereditary spastic paraplegias (HSPs) are caused by a length-dependent axonopathy of long corticospinal neurons, but how axons of these cortical projection neurons (PNs) degenerate remains elusive. We generated isogenic human pluripotent stem cell (hPSC) lines for two ATL1 missense mutations associated with SPG3A, the most common early-onset autosomal dominant HSP. In hPSC-derived cortical PNs, ATL1 mutations resulted in reduced axonal outgrowth, impaired axonal transport, and accumulated axonal swellings, recapitulating disease-specific phenotypes. Importantly, ATL1 mutations dysregulated proteolipid gene expression, reduced lipid droplet size in astrocytes, and unexpectedly disrupted cholesterol transfer from glia to neurons, leading to cholesterol deficiency in SPG3A cortical PNs. Applying cholesterol or conditioned medium from control astrocytes, a major source of cholesterol in the brain, rescued aberrant axonal transport and swellings in SPG3A cortical PNs. Furthermore, treatment with the NR1H2 agonist GW3965 corrected lipid droplet defects in SPG3A astrocytes and promoted cholesterol efflux from astrocytes, leading to restoration of cholesterol levels and rescue of axonal degeneration in SPG3A cortical PNs. These results reveal a non-cell autonomous mechanism underlying axonal degeneration of cortical PNs mediated by impaired cholesterol homeostasis in glia.
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21
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22
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Unrestrained ESCRT-III drives micronuclear catastrophe and chromosome fragmentation. Nat Cell Biol 2020; 22:856-867. [PMID: 32601372 DOI: 10.1038/s41556-020-0537-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 05/24/2020] [Indexed: 12/11/2022]
Abstract
The ESCRT-III membrane fission machinery maintains the integrity of the nuclear envelope. Although primary nuclei resealing takes minutes, micronuclear envelope ruptures seem to be irreversible. Instead, micronuclear ruptures result in catastrophic membrane collapse and are associated with chromosome fragmentation and chromothripsis, complex chromosome rearrangements thought to be a major driving force in cancer development. Here we use a combination of live microscopy and electron tomography, as well as computer simulations, to uncover the mechanism underlying micronuclear collapse. We show that, due to their small size, micronuclei inherently lack the capacity of primary nuclei to restrict the accumulation of CHMP7-LEMD2, a compartmentalization sensor that detects loss of nuclear integrity. This causes unrestrained ESCRT-III accumulation, which drives extensive membrane deformation, DNA damage and chromosome fragmentation. Thus, the nuclear-integrity surveillance machinery is a double-edged sword, as its sensitivity ensures rapid repair at primary nuclei while causing unrestrained activity at ruptured micronuclei, with catastrophic consequences for genome stability.
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23
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Affiliation(s)
- Maaran Michael Rajah
- Institut Pasteur, Virus and Immunity Unit, CNRS-UMR3569, Paris, France
- Ecole Doctorale Bio Sorbonne Paris Cité (BioSPC) -Université de Paris, Paris, France
| | - Blandine Monel
- Institut Pasteur, Virus and Immunity Unit, CNRS-UMR3569, Paris, France
- * E-mail: (BM); (OS)
| | - Olivier Schwartz
- Institut Pasteur, Virus and Immunity Unit, CNRS-UMR3569, Paris, France
- Vaccine Research Institute, Creteil, France
- * E-mail: (BM); (OS)
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24
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Rempel IL, Popken P, Ghavami A, Mishra A, Hapsari RA, Wolters AHG, Veldsink AC, Klaassens M, Meinema AC, Poolman B, Giepmans BNG, Onck PR, Steen A, Veenhoff LM. Flexible and Extended Linker Domains Support Efficient Targeting of Heh2 to the Inner Nuclear Membrane. Structure 2020; 28:185-195.e5. [PMID: 31806352 DOI: 10.1016/j.str.2019.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 08/09/2019] [Accepted: 11/08/2019] [Indexed: 10/25/2022]
Abstract
The nuclear pore complex (NPC) is embedded in the nuclear envelope and forms the main gateway to the nuclear interior including the inner nuclear membrane (INM). Two INM proteins in yeast are selectively imported. Their sorting signals consist of a nuclear localization signal, separated from the transmembrane domain by a long intrinsically disordered (ID) linker. We used computational models to predict the dynamic conformations of ID linkers and analyzed the INM targeting efficiency of proteins with linker regions with altered Stokes radii and decreased flexibilities. We find that flexibility, Stokes radius, and the frequency at which the linkers are at an extended end-to-end distance larger than 25 nm are good predictors for the targeting of the proteins. The data are consistent with a transport mechanism in which INM targeting of Heh2 is dependent on an ID linker that facilitates the crossing of the approximately 25-nm thick NPC scaffold.
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Affiliation(s)
- Irina L Rempel
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Petra Popken
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands; Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands; Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Ali Ghavami
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Ankur Mishra
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Rizqiya A Hapsari
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Anouk H G Wolters
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Annemiek C Veldsink
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Marindy Klaassens
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Anne C Meinema
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Bert Poolman
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands; Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands
| | - Ben N G Giepmans
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands.
| | - Anton Steen
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands.
| | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, Netherlands.
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25
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Neufeldt CJ, Cortese M, Scaturro P, Cerikan B, Wideman JG, Tabata K, Moraes T, Oleksiuk O, Pichlmair A, Bartenschlager R. ER-shaping atlastin proteins act as central hubs to promote flavivirus replication and virion assembly. Nat Microbiol 2019; 4:2416-2429. [PMID: 31636417 PMCID: PMC6881184 DOI: 10.1038/s41564-019-0586-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 09/10/2019] [Indexed: 12/13/2022]
Abstract
Flaviviruses, including dengue virus (DV) and Zika virus, extensively remodel the cellular endomembrane network to generate replication organelles that promote viral genome replication and virus production. However, it remains unclear how these membranes and associated cellular proteins act during the virus cycle. Here, we show that atlastins (ATLs), a subset of ER resident proteins involved in neurodegenerative diseases, have dichotomous effects on flaviviruses with ATL2 depletion leading to replication organelle defects and ATL3 depletion to changes in virus production pathways. We characterized non-conserved functional domains in ATL paralogues and show that the ATL interactome is profoundly reprogrammed upon DV infection. Screen analysis confirmed non-redundant ATL functions and identified a specific role for ATL3, and its interactor ARF4, in vesicle trafficking and virion maturation. Our data identify ATLs as central hubs targeted by flaviviruses to establish their replication organelle and to achieve efficient virion maturation and secretion.
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Affiliation(s)
- Christopher J Neufeldt
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany.
| | - Mirko Cortese
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Pietro Scaturro
- Technical University of Munich, School of Medicine, Institute of Virology, Munich, Germany
| | - Berati Cerikan
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Jeremy G Wideman
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.,Biodesign Center for Mechanisms of Evolution, School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Keisuke Tabata
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Thaís Moraes
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Olga Oleksiuk
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Andreas Pichlmair
- Technical University of Munich, School of Medicine, Institute of Virology, Munich, Germany.,German Center for Infection Research (DZIF), (Munich Partner Site), Munich, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany. .,German Center for Infection Research (DZIF), (Heidelberg Partner Site), Heidelberg, Germany. .,Division Virus-Associated Carcinogenesis, German Cancer Research Center, Heidelberg, Germany.
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26
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Atlastin-mediated membrane tethering is critical for cargo mobility and exit from the endoplasmic reticulum. Proc Natl Acad Sci U S A 2019; 116:14029-14038. [PMID: 31239341 PMCID: PMC6628656 DOI: 10.1073/pnas.1908409116] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
In the early secretory pathway, newly synthesized proteins undergo folding and modifications and then leave the ER through COPII-coated vesicles. How these processes are coordinated and maintained are important but mostly unclear. We show here that ATL, a GTPase that connects ER tubules, controls ER protein mobility and regulates cargo packaging and coat assembly of COPII vesicles. The tethering and fusion activity by ATL likely maintains tension and other necessary parameters for COPII formation in ER membranes. These findings reveal a role of ER shaping in the early secretory pathway and provide insight into behaviors of ER exportation. Endoplasmic reticulum (ER) membrane junctions are formed by the dynamin-like GTPase atlastin (ATL). Deletion of ATL results in long unbranched ER tubules in cells, and mutation of human ATL1 is linked to hereditary spastic paraplegia. Here, we demonstrate that COPII formation is drastically decreased in the periphery of ATL-deleted cells. ER export of cargo proteins becomes defective; ER exit site initiation is not affected, but many of the sites fail to recruit COPII subunits. The efficiency of cargo packaging into COPII vesicles is significantly reduced in cells lacking ATLs, or when the ER is transiently fragmented. Cargo is less mobile in the ER in the absence of ATL, but the cargo mobility and COPII formation can be restored by ATL R77A, which is capable of tethering, but not fusing, ER tubules. These findings suggest that the generation of ER junctions by ATL plays a critical role in maintaining the necessary mobility of ER contents to allow efficient packaging of cargo proteins into COPII vesicles.
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27
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Behrendt L, Kurth I, Kaether C. A disease causing ATLASTIN 3 mutation affects multiple endoplasmic reticulum-related pathways. Cell Mol Life Sci 2019; 76:1433-1445. [PMID: 30666337 PMCID: PMC6420906 DOI: 10.1007/s00018-019-03010-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 12/01/2022]
Abstract
Atlastins (ATLs) are membrane-bound GTPases involved in shaping of the endoplasmic reticulum (ER). Mutations in ATL1 and ATL3 cause spastic paraplegia and hereditary sensory neuropathy. We here show that the sensory neuropathy causing ATL3 Y192C mutation reduces the complexity of the tubular ER-network. ATL3 Y192C delays ER-export by reducing the number of ER exit sites, reduces autophagy, fragments the Golgi and causes malformation of the nucleus. In cultured primary neurons, ATL3 Y192C does not localize to the growing axon, resulting in axon growth deficits. Patient-derived fibroblasts possess a tubular ER with reduced complexity and have a reduced number of autophagosomes. The data suggest that the disease-causing ATL3 Y192C mutation affects multiple ER-related pathways, possibly as a consequence of the distorted ER morphology.
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Affiliation(s)
- Laura Behrendt
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Beutenbergstr. 11, 07745, Jena, Germany
| | - Ingo Kurth
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
| | - Christoph Kaether
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Beutenbergstr. 11, 07745, Jena, Germany.
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28
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Chen Q, Xiao Y, Chai P, Zheng P, Teng J, Chen J. ATL3 Is a Tubular ER-Phagy Receptor for GABARAP-Mediated Selective Autophagy. Curr Biol 2019; 29:846-855.e6. [PMID: 30773365 DOI: 10.1016/j.cub.2019.01.041] [Citation(s) in RCA: 192] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 12/06/2018] [Accepted: 01/15/2019] [Indexed: 12/30/2022]
Abstract
The endoplasmic reticulum (ER) consists of the nuclear envelope and both peripheral ER sheets and a peripheral tubular network [1, 2]. In response to physiological or pathological conditions, receptor-mediated selective ER-phagy, engulfing specific ER subdomains or components, is essential for ER turnover and homeostasis [3-6]. Four mammalian receptors for ER-phagy have been reported: FAM134B [7], reticulon 3 (RTN3) [8], SEC62 [9], and CCPG1 [10]. However, these ER-phagy receptors function in subcellular- and tissue- or physiological- and pathological-condition-specific manners, so the diversity of ER-phagy receptors and underlying mechanisms remain largely unknown [3, 4]. Atlastins (ATL1, ATL2, and ATL3), in mammals, are a class of membrane-bound, dynamin-like GTPases that function in ER fusion [11, 12]. ATL1 is expressed mainly in the central nervous system, while ATL2 and ATL3 are more ubiquitously distributed [13]. Recent studies showed that ATL2 mainly affects ER morphology by promoting ER fusion, whereas alterations in ER morphology are hardly detectable after ATL3 depletion [14, 15]. Here, we show that ATL3 functions as a receptor for ER-phagy, promoting tubular ER degradation upon starvation. ATL3 specifically binds to GABARAP, but not LC3, subfamily proteins via 2 GABARAP interaction motifs (GIMs). ATL3-GABARAP interaction is essential for ATL3 to function in ER-phagy. Moreover, hereditary sensory and autonomic neuropathy type I (HSAN I)-associated ATL3 mutations (Y192C and P338R) disrupt ATL3's association with GABARAP and impair ATL3's function in ER-phagy, suggesting that defective ER-phagy is involved in HSAN I. Therefore, we reveal a new ATL3 function for GABARAP-mediated ER-phagy in the degradation of tubular ER.
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Affiliation(s)
- Qingzhou Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Ya Xiao
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Peiyuan Chai
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Pengli Zheng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Junlin Teng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China.
| | - Jianguo Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China; Center for Quantitative Biology, Peking University, Beijing 100871, China.
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29
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Steiner B, Weber S, Kaech A, Ziegler U, Hilbi H. The large GTPase atlastin controls ER remodeling around a pathogen vacuole. Commun Integr Biol 2018; 11:1-5. [PMID: 30083282 PMCID: PMC6067846 DOI: 10.1080/19420889.2018.1440880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/04/2018] [Indexed: 12/22/2022] Open
Abstract
The ubiquitous environmental bacterium Legionella pneumophila is the causative agent of Legionnaires' pneumonia and replicates in free-living protozoa and mammalian macrophages in a specific compartment, the Legionella-containing vacuole (LCV). LCVs communicate with the endosomal, retrograde and secretory vesicle trafficking pathway, and eventually tightly interact with the endoplasmic reticulum (ER). In Dictyostelium discoideum amoebae and macrophages, the ER tubule-resident large GTPase Sey1/atlastin3 (Atl3) accumulates on LCVs and promotes LCV expansion and intracellular replication of L. pneumophila. Fluorescence microscopy of D. discoideum infected with L. pneumophila indicated that Sey1 is involved in extensive ER remodeling around LCVs. An ultrastructural analysis confirmed these findings. Moreover, dominant negative Sey1_K154A compromises ER accumulation on LCVs and causes an aberrant ER morphology in uninfected D. discoideum as well as in amoebae infected with avirulent L. pneumophila that lack a functional type IV secretion system. Thus, the large, dynamin-like GTPase Sey1/Atl3 controls circumferential ER remodeling during LCV maturation.
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Affiliation(s)
- Bernhard Steiner
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Stephen Weber
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zürich, Zürich, Switzerland
| | - Urs Ziegler
- Center for Microscopy and Image Analysis, University of Zürich, Zürich, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
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30
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Abstract
Efficient targeting of newly synthesized membrane proteins from the endoplasmic reticulum to the inner nuclear membrane depends on nucleotide hydrolysis. A new study shows that this dependence reflects critical actions of the atlastin family of GTPases in maintaining the morphology of the endoplasmic reticulum network.
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Affiliation(s)
- Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Room 2A-201, 9000 Rockville Pike, Bethesda MD 20892, USA.
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31
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Helle SCJ, Feng Q, Aebersold MJ, Hirt L, Grüter RR, Vahid A, Sirianni A, Mostowy S, Snedeker JG, Šarić A, Idema T, Zambelli T, Kornmann B. Mechanical force induces mitochondrial fission. eLife 2017; 6. [PMID: 29119945 PMCID: PMC5679753 DOI: 10.7554/elife.30292] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 10/28/2017] [Indexed: 12/17/2022] Open
Abstract
Eukaryotic cells are densely packed with macromolecular complexes and intertwining organelles, continually transported and reshaped. Intriguingly, organelles avoid clashing and entangling with each other in such limited space. Mitochondria form extensive networks constantly remodeled by fission and fusion. Here, we show that mitochondrial fission is triggered by mechanical forces. Mechano-stimulation of mitochondria – via encounter with motile intracellular pathogens, via external pressure applied by an atomic force microscope, or via cell migration across uneven microsurfaces – results in the recruitment of the mitochondrial fission machinery, and subsequent division. We propose that MFF, owing to affinity for narrow mitochondria, acts as a membrane-bound force sensor to recruit the fission machinery to mechanically strained sites. Thus, mitochondria adapt to the environment by sensing and responding to biomechanical cues. Our findings that mechanical triggers can be coupled to biochemical responses in membrane dynamics may explain how organelles orderly cohabit in the crowded cytoplasm.
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Affiliation(s)
| | - Qian Feng
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Mathias J Aebersold
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland
| | - Luca Hirt
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland
| | - Raphael R Grüter
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland
| | - Afshin Vahid
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands
| | - Andrea Sirianni
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Serge Mostowy
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Jess G Snedeker
- Balgrist University Hospital, University of Zurich, Zurich, Switzerland.,Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Anđela Šarić
- Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, London, United Kingdom
| | - Timon Idema
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands
| | - Tomaso Zambelli
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland
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