1
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Lupi M, Avanzato D, Confalonieri S, Martino F, Pennisi R, Pupo E, Audrito V, Freddi S, Bertalot G, Montani F, Matoskova B, Sigismund S, Di Fiore PP, Lanzetti L. TBC1 domain-containing proteins are frequently involved in triple-negative breast cancers in connection with the induction of a glycolytic phenotype. Cell Death Dis 2024; 15:647. [PMID: 39231952 PMCID: PMC11375060 DOI: 10.1038/s41419-024-07037-2] [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: 04/10/2024] [Revised: 08/24/2024] [Accepted: 08/27/2024] [Indexed: 09/06/2024]
Abstract
Metabolic plasticity is a hallmark of cancer, and metabolic alterations represent a promising therapeutic target. Since cellular metabolism is controlled by membrane traffic at multiple levels, we investigated the involvement of TBC1 domain-containing proteins (TBC1Ds) in the regulation of cancer metabolism. These proteins are characterized by the presence of a RAB-GAP domain, the TBC1 domain, and typically function as attenuators of RABs, the master switches of membrane traffic. However, a number of TBC1Ds harbor mutations in their catalytic residues, predicting biological functions different from direct regulation of RAB activities. Herein, we report that several genes encoding for TBC1Ds are expressed at higher levels in triple-negative breast cancers (TNBC) vs. other subtypes of breast cancers (BC), and predict prognosis. Orthogonal transcriptomics/metabolomics analysis revealed that the expression of prognostic TBC1Ds correlates with elevated glycolytic metabolism in BC cell lines. In-depth investigations of the three top hits from the previous analyses (TBC1D31, TBC1D22B and TBC1D7) revealed that their elevated expression is causal in determining a glycolytic phenotype in TNBC cell lines. We further showed that the impact of TBC1D7 on glycolytic metabolism of BC cells is independent of its known participation in the TSC1/TSC2 complex and consequent downregulation of mTORC1 activity. Since TBC1D7 behaves as an independent prognostic biomarker in TNBC, it could be used to distinguish good prognosis patients who could be spared aggressive therapy from those with a poor prognosis who might benefit from anti-glycolytic targeted therapies. Together, our results highlight how TBC1Ds connect disease aggressiveness with metabolic alterations in TNBC. Given the high level of heterogeneity among this BC subtype, TBC1Ds could represent important tools in predicting prognosis and guiding therapy decision-making.
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Grants
- IG #22811 Associazione Italiana per la Ricerca sul Cancro (Italian Association for Cancer Research)
- MFAG-2021 #26004 Associazione Italiana per la Ricerca sul Cancro (Italian Association for Cancer Research)
- IG #24415 Associazione Italiana per la Ricerca sul Cancro (Italian Association for Cancer Research)
- IG #23060 Associazione Italiana per la Ricerca sul Cancro (Italian Association for Cancer Research)
- PRIN 2020 Prot. 2020R2BP2E Ministero dell'Istruzione, dell'Università e della Ricerca (Ministry of Education, University and Research)
- PRIN 2022 Prot. 2022W93FTW Ministero dell'Istruzione, dell'Università e della Ricerca (Ministry of Education, University and Research)
- PRIN 2020 Prot. 2020R2BP2E Ministero dell'Istruzione, dell'Università e della Ricerca (Ministry of Education, University and Research)
- Ricerca Corrente 2023-2024 Ministero della Salute (Ministry of Health, Italy)
- 5x1000 Ministero della Salute (Ministry of Health, Italy)
- Ricerca Corrente 2023-2024 Ministero della Salute (Ministry of Health, Italy)
- 5x1000 Ministero della Salute (Ministry of Health, Italy)
- Ricerca Finalizzata RF-2021-12373957 Ministero della Salute (Ministry of Health, Italy)
- Ricerca Corrente 2023-2024 Ministero della Salute (Ministry of Health, Italy)
- 5x1000 Ministero della Salute (Ministry of Health, Italy)
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Affiliation(s)
- Mariadomenica Lupi
- Department of Oncology, University of Torino Medical School, Turin, Italy
- Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Daniele Avanzato
- Department of Oncology, University of Torino Medical School, Turin, Italy
- Department of Veterinary Sciences, Infectious Diseases Unit, University of Torino, Turin, Italy
| | | | - Flavia Martino
- Department of Oncology, University of Torino Medical School, Turin, Italy
- Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Rosa Pennisi
- Department of Oncology, University of Torino Medical School, Turin, Italy
- Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | | | - Valentina Audrito
- Department of Science and Technological Innovation (DISIT), University of Eastern Piedmont, Alessandria, Italy
| | - Stefano Freddi
- IEO, European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Haemato-Oncology, University of Milan, Milan, Italy
| | - Giovanni Bertalot
- IEO, European Institute of Oncology IRCCS, Milan, Italy
- Unità Operativa Multizonale di Anatomia Patologica, APSS, Trento, Italy, and Centre for Medical Sciences - CISMed, University of Trento, Trento, Italy
| | | | | | - Sara Sigismund
- IEO, European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Haemato-Oncology, University of Milan, Milan, Italy
| | - Pier Paolo Di Fiore
- IEO, European Institute of Oncology IRCCS, Milan, Italy.
- Department of Oncology and Haemato-Oncology, University of Milan, Milan, Italy.
| | - Letizia Lanzetti
- Department of Oncology, University of Torino Medical School, Turin, Italy.
- Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy.
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2
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Shvarev D, König C, Susan N, Langemeyer L, Walter S, Perz A, Fröhlich F, Ungermann C, Moeller A. Structure of the endosomal CORVET tethering complex. Nat Commun 2024; 15:5227. [PMID: 38898033 PMCID: PMC11187117 DOI: 10.1038/s41467-024-49137-9] [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: 11/09/2023] [Accepted: 05/24/2024] [Indexed: 06/21/2024] Open
Abstract
Cells depend on their endolysosomal system for nutrient uptake and downregulation of plasma membrane proteins. These processes rely on endosomal maturation, which requires multiple membrane fusion steps. Early endosome fusion is promoted by the Rab5 GTPase and its effector, the hexameric CORVET tethering complex, which is homologous to the lysosomal HOPS. How these related complexes recognize their specific target membranes remains entirely elusive. Here, we solve the structure of CORVET by cryo-electron microscopy and revealed its minimal requirements for membrane tethering. As expected, the core of CORVET and HOPS resembles each other. However, the function-defining subunits show marked structural differences. Notably, we discover that unlike HOPS, CORVET depends not only on Rab5 but also on phosphatidylinositol-3-phosphate (PI3P) and membrane lipid packing defects for tethering, implying that an organelle-specific membrane code enables fusion. Our data suggest that both shape and membrane interactions of CORVET and HOPS are conserved in metazoans, thus providing a paradigm how tethering complexes function.
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Affiliation(s)
- Dmitry Shvarev
- Department of Biology/Chemistry, Structural Biology Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Caroline König
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Nicole Susan
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany
| | - Angela Perz
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Florian Fröhlich
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany
- Department of Biology/Chemistry, Bioanalytical Chemistry Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany.
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany.
| | - Arne Moeller
- Department of Biology/Chemistry, Structural Biology Section, Osnabrück University, 49076, Osnabrück, Germany.
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany.
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3
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Füllbrunn N, Nicastro R, Mari M, Griffith J, Herrmann E, Rasche R, Borchers AC, Auffarth K, Kümmel D, Reggiori F, De Virgilio C, Langemeyer L, Ungermann C. The GTPase activating protein Gyp7 regulates Rab7/Ypt7 activity on late endosomes. J Cell Biol 2024; 223:e202305038. [PMID: 38536036 PMCID: PMC10978497 DOI: 10.1083/jcb.202305038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 01/22/2024] [Accepted: 03/08/2024] [Indexed: 04/01/2024] Open
Abstract
Organelles of the endomembrane system contain Rab GTPases as identity markers. Their localization is determined by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). It remains largely unclear how these regulators are specifically targeted to organelles and how their activity is regulated. Here, we focus on the GAP Gyp7, which acts on the Rab7-like Ypt7 protein in yeast, and surprisingly observe the protein exclusively in puncta proximal to the vacuole. Mistargeting of Gyp7 to the vacuole strongly affects vacuole morphology, suggesting that endosomal localization is needed for function. In agreement, efficient endolysosomal transport requires Gyp7. In vitro assays reveal that Gyp7 requires a distinct lipid environment for membrane binding and activity. Overexpression of Gyp7 concentrates Ypt7 in late endosomes and results in resistance to rapamycin, an inhibitor of the target of rapamycin complex 1 (TORC1), suggesting that these late endosomes are signaling endosomes. We postulate that Gyp7 is part of regulatory machinery involved in late endosome function.
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Affiliation(s)
- Nadia Füllbrunn
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück University, Osnabrück, Germany
| | - Raffaele Nicastro
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Muriel Mari
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Janice Griffith
- Department of Cell Biology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Eric Herrmann
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - René Rasche
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - Ann-Christin Borchers
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Kathrin Auffarth
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - Fulvio Reggiori
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Cell Biology, University Medical Center Utrecht, Utrecht, Netherlands
| | | | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück University, Osnabrück, Germany
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4
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Feathers JR, Vignogna RC, Fromme JC. Structural basis for Rab6 activation by the Ric1-Rgp1 complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.06.592747. [PMID: 38766083 PMCID: PMC11100747 DOI: 10.1101/2024.05.06.592747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Rab GTPases act as molecular switches to regulate organelle homeostasis and membrane trafficking. Rab6 plays a central role in regulating cargo flux through the Golgi and is activated via nucleotide exchange by the Ric1-Rgp1 protein complex. Ric1-Rgp1 is conserved throughout eukaryotes but the structural and mechanistic basis for its function has not been established. Here we report the cryoEM structure of a Ric1-Rgp1-Rab6 complex representing a key intermediate of the nucleotide exchange reaction. This structure reveals the overall architecture of the complex and enabled us to identify interactions critical for proper recognition and activation of Rab6 on the Golgi membrane surface. Ric1-Rgp1 interacts with the nucleotide-binding domain of Rab6 using an uncharacterized helical domain, which we establish as a novel RabGEF domain by identifying residues required for Rab6 nucleotide exchange. Unexpectedly, the complex uses an arrestin fold to interact with the Rab6 hypervariable domain, indicating that interactions with the unstructured C-terminal regions of Rab GTPases may be a common specificity mechanism used by their activators. Collectively, our findings provide a detailed mechanistic understanding of regulated Rab6 activation at the Golgi.
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Affiliation(s)
- J. Ryan Feathers
- Department of Molecular Biology & Genetics and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14850 USA
- Current address: 201 Schultz Laboratory, Princeton University, Princeton, NJ 08544 USA
| | - Ryan C. Vignogna
- Department of Molecular Biology & Genetics and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14850 USA
| | - J. Christopher Fromme
- Department of Molecular Biology & Genetics and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14850 USA
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5
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Chatterjee R, Setty SRG, Chakravortty D. SNAREs: a double-edged sword for intravacuolar bacterial pathogens within host cells. Trends Microbiol 2024; 32:477-493. [PMID: 38040624 DOI: 10.1016/j.tim.2023.11.002] [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: 08/05/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 12/03/2023]
Abstract
In the tug-of-war between host and pathogen, both evolve to combat each other's defence arsenals. Intracellular phagosomal bacteria have developed strategies to modify the vacuolar niche to suit their requirements best. Conversely, the host tries to target the pathogen-containing vacuoles towards the degradative pathways. The host cells use a robust system through intracellular trafficking to maintain homeostasis inside the cellular milieu. In parallel, intracellular bacterial pathogens have coevolved with the host to harbour strategies to manipulate cellular pathways, organelles, and cargoes, facilitating the conversion of the phagosome into a modified pathogen-containing vacuole (PCV). Key molecular regulators of intracellular traffic, such as changes in the organelle (phospholipid) composition, recruitment of small GTPases and associated effectors, soluble N-ethylmaleimide-sensitive factor-activating protein receptors (SNAREs), etc., are hijacked to evade lysosomal degradation. Legionella, Salmonella, Coxiella, Chlamydia, Mycobacterium, and Brucella are examples of pathogens which diverge from the endocytic pathway by using effector-mediated mechanisms to overcome the challenges and establish their intracellular niches. These pathogens extensively utilise and modulate the end processes of secretory pathways, particularly SNAREs, in repurposing the PCV into specialised compartments resembling the host organelles within the secretory network; at the same time, they avoid being degraded by the host's cellular mechanisms. Here, we discuss the recent research advances on the host-pathogen interaction/crosstalk that involves host SNAREs, conserved cellular processes, and the ongoing host-pathogen defence mechanisms in the molecular arms race against each other. The current knowledge of SNAREs, and intravacuolar bacterial pathogen interactions, enables us to understand host cellular innate immune pathways, maintenance of homeostasis, and potential therapeutic strategies to combat ever-growing antimicrobial resistance.
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Affiliation(s)
- Ritika Chatterjee
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka, India
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka, India.
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka, India; Adjunct Faculty, Indian Institute of Science Research and Education, Thiruvananthapuram, Kerala, India.
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6
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Guan L, Wen X, Zhang Z, Wang L, Zhang X, Yang M, Wang S, Qin Q. Grouper Rab1 inhibits nodovirus infection by affecting virus entry and host immune response. FISH & SHELLFISH IMMUNOLOGY 2023; 143:109136. [PMID: 37839541 DOI: 10.1016/j.fsi.2023.109136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/29/2023] [Accepted: 10/02/2023] [Indexed: 10/17/2023]
Abstract
Rab1, a GTPase, is present in all eukaryotes, and is mainly involved in vesicle trafficking between the endoplasmic reticulum and Golgi, thereby regulating many cellular activities and pathogenic infections. However, little is known of how Rab1 functions in fish during virus infection. Groupers (Epinephelus spp.) are high in economic value and widely cultivated in China and Southeast Asia, although they often suffer from diseases. Red-spotted grouper nervous necrosis virus (RGNNV), a highly pathogenic RNA virus, is a major pathogen in cultured groupers, and causes huge economic losses. A series of host cellular proteins involved in RGNNV infection was identified. However, the impact of Rab1 on RGNNV infection has not yet been reported. In this study, a novel Rab1 homolog (EcRab1) from Epinephelus coioides was cloned, and its roles during virus infection and host immune responses were investigated. EcRab1 encoded a 202 amino acid polypeptide, showing 98% and 78% identity to Epinephelus lanceolatus and Homo sapiens, respectively. After challenge with RGNNV or poly(I:C), the transcription of EcRab1 was altered both in vitro and in vivo, implying that EcRab1 was involved in virus infection. Subcellular localization showed that EcRab1 was displayed as punctate structures in the cytoplasm, which was affected by EcRab1 mutants. The dominant negative (DN) EcRab1, enabling EcRab1 to remain in the GDP-binding state, caused EcRab1 to be diffusely distributed in the cytoplasm. Constitutively active (CA) EcRab1, enabling EcRab1 to remain in the GTP-binding state, induced larger cluster structures of EcRab1. During the late stage of RGNNV infection, some EcRab1 co-localized with RGNNV, and the size of EcRab1 clusters was enlarged. Importantly, overexpression of EcRab1 significantly inhibited RGNNV infection, and knockdown of EcRab1 promoted RGNNV infection. Furthermore, EcRab1 inhibited the entry of RGNNV to host cells. Compared with EcRab1, overexpression of DN EcRab1 or CA EcRab1 also promoted RGNNV infection, suggesting that EcRab1 regulated RGNNV infection, depending on the cycles of GTP- and GDP-binding states. In addition, EcRab1 positively regulated interferon (IFN) immune and inflammatory responses. Taken together, these results suggest that EcRab1 affects RGNNV infection, possibly by regulating host immunity. Our study furthers the understanding of Rab1 function during virus infection, thus helping to design new antiviral strategies.
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Affiliation(s)
- Lingfeng Guan
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Xiaozhi Wen
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Zihan Zhang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Liqun Wang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Xinyue Zhang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Min Yang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Shaowen Wang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, 511464, China.
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, 511464, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519000, China.
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7
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Kim MJ, Moon EK, Jo HJ, Quan FS, Kong HH. Phagocytosis-associated genes in Acanthamoeba castellanii feeding on Escherichia coli. PARASITES, HOSTS AND DISEASES 2023; 61:397-404. [PMID: 38043535 PMCID: PMC10693966 DOI: 10.3347/phd.23088] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 10/09/2023] [Indexed: 12/05/2023]
Abstract
Acanthamoeba species are free-living amoebae those are widely distributed in the environment. They feed on various microorganisms, including bacteria, fungi, and algae. Although majority of the microbes phagocytosed by Acanthamoeba spp. are digested, some pathogenic bacteria thrive within them. Here, we identified the roles of 3 phagocytosis-associated genes (ACA1_077100, ACA1_175060, and AFD36229.1) in A. castellanii. These 3 genes were upregulated after the ingestion of Escherichia coli. However, after the ingestion of Legionella pneumophila, the expression of these 3 genes was not altered after the consumption of L. pneumophila. Furthermore, A. castellanii transfected with small interfering RNS (siRNA) targeting the 3 phagocytosis-associated genes failed to digest phagocytized E. coli. Silencing of ACA1_077100 disabled phagosome formation in the E. coli-ingesting A. castellanii. Alternatively, silencing of ACA1_175060 enabled phagosome formation; however, phagolysosome formation was inhibited. Moreover, suppression of AFD36229.1 expression prevented E. coli digestion and consequently led to the rupturing of A. castellanii. Our results demonstrated that the ACA1_077100, ACA1_175060, and AFD36229.1 genes of Acanthamoeba played crucial roles not only in the formation of phagosome and phagolysosome but also in the digestion of E. coli.
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Affiliation(s)
- Min-Jeong Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447,
Korea
| | - Eun-Kyung Moon
- Department of Medical Zoology, Kyung Hee University School of Medicine, Seoul 02447,
Korea
| | - Hye-Jeong Jo
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447,
Korea
| | - Fu-Shi Quan
- Department of Medical Zoology, Kyung Hee University School of Medicine, Seoul 02447,
Korea
- Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, Core Research Institute, School of Medicine, Kyung Hee University, Seoul 02447,
Korea
| | - Hyun-Hee Kong
- Department of Parasitology, Dong-A University College of Medicine, Busan 49201,
Korea
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8
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Lui K, Huang Y, Sheikh MS, Cheung KK, Tam WY, Sun KT, Cheng KM, Ng WWM, Loh AWK. The oncogenic potential of Rab-like protein 1A (RBEL1A) GTPase: The first review of RBEL1A research with future research directions and challenges. J Cancer 2023; 14:3214-3226. [PMID: 37928422 PMCID: PMC10622986 DOI: 10.7150/jca.84267] [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: 03/13/2023] [Accepted: 09/12/2023] [Indexed: 11/07/2023] Open
Abstract
Research on Rab-like protein 1A (RBEL1A) in the past two decades highlighted the oncogenic properties of this gene. Despite the emerging evidence, its importance in cancer biology was underrated. This is the first RBEL1A critical review covering its discovery, biochemistry, physiological functions, and clinical insights. RBEL1A expression at the appropriate levels appears essential in normal cells and tissues to maintain chromosomal stability; however, its overexpression is linked to tumorigenesis. Furthermore, the upstream and downstream targets of the RBEL1A signaling pathways will be discussed. Mechanistically, RBEL1A promotes cell proliferation signals by enhancing the Erk1/2, Akt, c-Myc, and CDK pathways while blunting the apoptotic signals via inhibitions on p53, Rb, and caspase pathways. More importantly, this review covers the clinical relevance of RBEL1A in the cancer field, such as drug resistance and poor overall survival rate. Also, this review points out the bottle-necks of the RBEL1A research and its future research directions. It is becoming clear that RBEL1A could potentially serve as a valuable target of anticancer therapy. Genetic and pharmacological researches are expected to facilitate the identification and development of RBEL1A inhibitors as cancer therapeutics in the future, which could undoubtedly improve the management of human malignancy.
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Affiliation(s)
- Ki Lui
- School of Nursing and Health Studies, Hong Kong Metropolitan University, Hong Kong
| | - Ying Huang
- Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, New York, USA
| | - M. Saeed Sheikh
- Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, New York, USA
| | - Kwok-Kuen Cheung
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong
| | - Wing Yip Tam
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Keng-Ting Sun
- Division of Medical Sciences & Graduate Entry Medicine, School of Medicine, University of Nottingham, United Kingdom
| | - Ka Ming Cheng
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong
| | | | - Anthony Wai-Keung Loh
- Division of Science, Engineering and Health Studies (SEHS), College of Professional and Continuing Education, The Hong Kong Polytechnic University, Hong Kong
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9
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Wells A, Mendes CC, Castellanos F, Mountain P, Wright T, Wainwright SM, Stefana MI, Harris AL, Goberdhan DCI, Wilson C. A Rab6 to Rab11 transition is required for dense-core granule and exosome biogenesis in Drosophila secondary cells. PLoS Genet 2023; 19:e1010979. [PMID: 37844085 PMCID: PMC10602379 DOI: 10.1371/journal.pgen.1010979] [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: 04/21/2023] [Revised: 10/26/2023] [Accepted: 09/17/2023] [Indexed: 10/18/2023] Open
Abstract
Secretory cells in glands and the nervous system frequently package and store proteins destined for regulated secretion in dense-core granules (DCGs), which disperse when released from the cell surface. Despite the relevance of this dynamic process to diseases such as diabetes and human neurodegenerative disorders, our mechanistic understanding is relatively limited, because of the lack of good cell models to follow the nanoscale events involved. Here, we employ the prostate-like secondary cells (SCs) of the Drosophila male accessory gland to dissect the cell biology and genetics of DCG biogenesis. These cells contain unusually enlarged DCGs, which are assembled in compartments that also form secreted nanovesicles called exosomes. We demonstrate that known conserved regulators of DCG biogenesis, including the small G-protein Arf1 and the coatomer complex AP-1, play key roles in making SC DCGs. Using real-time imaging, we find that the aggregation events driving DCG biogenesis are accompanied by a change in the membrane-associated small Rab GTPases which are major regulators of membrane and protein trafficking in the secretory and endosomal systems. Indeed, a transition from trans-Golgi Rab6 to recycling endosomal protein Rab11, which requires conserved DCG regulators like AP-1, is essential for DCG and exosome biogenesis. Our data allow us to develop a model for DCG biogenesis that brings together several previously disparate observations concerning this process and highlights the importance of communication between the secretory and endosomal systems in controlling regulated secretion.
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Affiliation(s)
- Adam Wells
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Cláudia C. Mendes
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Felix Castellanos
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Phoebe Mountain
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Tia Wright
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - S. Mark Wainwright
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - M. Irina Stefana
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Adrian L. Harris
- Department of Oncology, University of Oxford, Oxford, United Kingdom
| | | | - Clive Wilson
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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10
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Localization of Chicken Rab22a in Cells and Its Relationship to BF or Ii Molecules and Genes. Animals (Basel) 2023; 13:ani13030387. [PMID: 36766276 PMCID: PMC9913282 DOI: 10.3390/ani13030387] [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: 12/03/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023] Open
Abstract
Rab22a is an important small GTPase protein the molecule that is involved in intracellular transportation and regulation of proteins. It also plays an important role in antigens uptake, transportation, regulation of endosome morphology, and also regulates the transport of antigens to MHC (Major Histocompatibility Complex) molecules. To investigate the role of Rab22a, the intracellular co-localization of chicken Rab22a (cRab22a) molecule and its relationship to BF and chicken invariant chain (cIi) molecules was studied. A 3D protein structure of Rab22a was constructed by using informatics tools (DNASTAR 4.0 and DNAMAN). Based on the model, the corresponding recombinant eukaryotic plasmids were constructed by point mutations in the protein's structural domains. HEK 293T cells were co-transfected with plasmids pEGFP-C1-cIi to observe the intracellular co-localization. Secondly, the DC2.4 Mouse Dendritic Cell and Murine RAW 264.7 cells were transfected with recombinant plasmids of pmCherry-cRab22a and pmCherry-mRab22a respectively. Subsequently, the intracellular localization of cRab22a in early and late endosomes was observed with specific antibodies against EEA1 and LAMP1 respectively. For gene expression-based studies, the cRab22a gene was down-regulated and up-regulated in HD11 cells, following the detection of transcription levels of the BFa (MHCIa) and cIi genes by real-time quantitative PCR (RT-qPCR). The interactions of the cRab22a gene with BFa and cIi were detected by co-immunoprecipitation (Co-IP) and Western blot. The results showed that the protein structures of chicken and mouse Rab22a were highly homologous (95.4%), and both localize to the early and late endosomes. Ser41 and Tyr74 are key amino acids in the Switch regions of Rab22a which maintain its intracellular localization. The down-regulation of cRab22a gene expression significantly reduced (p < 0.01) the transcription of BFa (MHCIa) and cIi in HD11 cells. However, when the expression of the cRab22a gene was increased 55 times as compared to control cells, the expression of the BFa (MHCIa) gene was increased 1.7 times compared to the control cells (p < 0.01), while the expression of the cIi gene did not significantly differ from control (p > 0.05). Western blot results showed that cRab22a could not directly bind to BFa and cIi. So, cRab22a can regulate BFa and cIi protein molecules indirectly. It is concluded that cRab22a was localized with cIi in the endosome. The Switch regions of cRab22a are the key domains that affect intracellular localization and colocalization of the cIi molecule.
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11
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Herrmann E, Langemeyer L, Auffarth K, Ungermann C, Kümmel D. Targeting of the Mon1-Ccz1 Rab guanine nucleotide exchange factor to distinct organelles by a synergistic protein and lipid code. J Biol Chem 2023; 299:102915. [PMID: 36649906 PMCID: PMC10124900 DOI: 10.1016/j.jbc.2023.102915] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 01/01/2023] [Accepted: 01/05/2023] [Indexed: 01/16/2023] Open
Abstract
Activation of the small GTPase Rab7 by its cognate guanine nucleotide exchange factor Mon1-Ccz1 (MC1) is a key step in the maturation of endosomes and autophagosomes. This process is tightly regulated and subject to precise spatiotemporal control of MC1 localization, but the mechanisms that underly MC1 localization have not been fully elucidated. We here identify and characterize an amphipathic helix in Ccz1, which is required for the function of Mon-Ccz1 in autophagy, but not endosomal maturation. Furthermore, our data show that the interaction of the Ccz1 amphipathic helix with lipid packing defects, binding of Mon1 basic patches to positively charged lipids, and association of MC1 with recruiter proteins collectively govern membrane recruitment of the complex in a synergistic and redundant manner. Membrane binding enhances MC1 activity predominantly by increasing enzyme and substrate concentration on the membrane, but interaction with recruiter proteins can further stimulate the guanine nucleotide exchange factor. Our data demonstrate that specific protein and lipid cues convey the differential targeting of MC1 to endosomes and autophagosomes. In conclusion, we reveal the molecular basis for how MC1 is adapted to recognize distinct target compartments by exploiting the unique biophysical properties of organelle membranes and thus provide a model for how the complex is regulated and activated independently in different functional contexts.
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Affiliation(s)
- Eric Herrmann
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Kathrin Auffarth
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany; Center of Cellular Nanoanalytics (CellNanOs), Osnabrück University, Osnabrück, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster, Münster, Germany.
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12
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Kümmel D, Herrmann E, Langemeyer L, Ungermann C. Molecular insights into endolysosomal microcompartment formation and maintenance. Biol Chem 2022; 404:441-454. [PMID: 36503831 DOI: 10.1515/hsz-2022-0294] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/22/2022] [Indexed: 12/14/2022]
Abstract
Abstract
The endolysosomal system of eukaryotic cells has a key role in the homeostasis of the plasma membrane, in signaling and nutrient uptake, and is abused by viruses and pathogens for entry. Endocytosis of plasma membrane proteins results in vesicles, which fuse with the early endosome. If destined for lysosomal degradation, these proteins are packaged into intraluminal vesicles, converting an early endosome to a late endosome, which finally fuses with the lysosome. Each of these organelles has a unique membrane surface composition, which can form segmented membrane microcompartments by membrane contact sites or fission proteins. Furthermore, these organelles are in continuous exchange due to fission and fusion events. The underlying machinery, which maintains organelle identity along the pathway, is regulated by signaling processes. Here, we will focus on the Rab5 and Rab7 GTPases of early and late endosomes. As molecular switches, Rabs depend on activating guanine nucleotide exchange factors (GEFs). Over the last years, we characterized the Rab7 GEF, the Mon1-Ccz1 (MC1) complex, and key Rab7 effectors, the HOPS complex and retromer. Structural and functional analyses of these complexes lead to a molecular understanding of their function in the context of organelle biogenesis.
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Affiliation(s)
- Daniel Kümmel
- Institute of Biochemistry, University of Münster , Corrensstraße 36 , D-48149 Münster , Germany
| | - Eric Herrmann
- Institute of Biochemistry, University of Münster , Corrensstraße 36 , D-48149 Münster , Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry section , Osnabrück University , Barbarastraße 13 , D-49076 Osnabrück , Germany
- Center of Cellular Nanoanalytics (CellNanOs) , Osnabrück University , Barbarastraße 11 , D-49076 Osnabrück , Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry section , Osnabrück University , Barbarastraße 13 , D-49076 Osnabrück , Germany
- Center of Cellular Nanoanalytics (CellNanOs) , Osnabrück University , Barbarastraße 11 , D-49076 Osnabrück , Germany
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13
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Bellucci A, Longhena F, Spillantini MG. The Role of Rab Proteins in Parkinson's Disease Synaptopathy. Biomedicines 2022; 10:biomedicines10081941. [PMID: 36009486 PMCID: PMC9406004 DOI: 10.3390/biomedicines10081941] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/31/2022] [Accepted: 08/08/2022] [Indexed: 12/29/2022] Open
Abstract
In patients affected by Parkinson's disease (PD), the most common neurodegenerative movement disorder, the brain is characterized by the loss of dopaminergic neurons in the nigrostriatal system, leading to dyshomeostasis of the basal ganglia network activity that is linked to motility dysfunction. PD mostly arises as an age-associated sporadic disease, but several genetic forms also exist. Compelling evidence supports that synaptic damage and dysfunction characterize the very early phases of either sporadic or genetic forms of PD and that this early PD synaptopathy drives retrograde terminal-to-cell body degeneration, culminating in neuronal loss. The Ras-associated binding protein (Rab) family of small GTPases, which is involved in the maintenance of neuronal vesicular trafficking, synaptic architecture and function in the central nervous system, has recently emerged among the major players in PD synaptopathy. In this manuscript, we provide an overview of the main findings supporting the involvement of Rabs in either sporadic or genetic PD pathophysiology, and we highlight how Rab alterations participate in the onset of early synaptic damage and dysfunction.
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Affiliation(s)
- Arianna Bellucci
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
- Correspondence: ; Tel.: +39-0303-717-380
| | - Francesca Longhena
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
- Department of Clinical Neurosciences, University of Cambridge, Clifford Albutt Building, Cambridge CB2 0AH, UK
| | - Maria Grazia Spillantini
- Department of Clinical Neurosciences, University of Cambridge, Clifford Albutt Building, Cambridge CB2 0AH, UK
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14
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Gao J, Nicastro R, Péli-Gulli MP, Grziwa S, Chen Z, Kurre R, Piehler J, De Virgilio C, Fröhlich F, Ungermann C. The HOPS tethering complex is required to maintain signaling endosome identity and TORC1 activity. J Biophys Biochem Cytol 2022; 221:213121. [PMID: 35404387 PMCID: PMC9011323 DOI: 10.1083/jcb.202109084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 01/27/2022] [Accepted: 02/28/2022] [Indexed: 12/04/2022] Open
Abstract
The endomembrane system of eukaryotic cells is essential for cellular homeostasis during growth and proliferation. Previous work showed that a central regulator of growth, namely the target of rapamycin complex 1 (TORC1), binds both membranes of vacuoles and signaling endosomes (SEs) that are distinct from multivesicular bodies (MVBs). Interestingly, the endosomal TORC1, which binds membranes in part via the EGO complex, critically defines vacuole integrity. Here, we demonstrate that SEs form at a branch point of the biosynthetic and endocytic pathways toward the vacuole and depend on MVB biogenesis. Importantly, function of the HOPS tethering complex is essential to maintain the identity of SEs and proper endosomal and vacuolar TORC1 activities. In HOPS mutants, the EGO complex redistributed to the Golgi, which resulted in a partial mislocalization of TORC1. Our study uncovers that SE function requires a functional HOPS complex and MVBs, suggesting a tight link between trafficking and signaling along the endolysosomal pathway.
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Affiliation(s)
- Jieqiong Gao
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Raffaele Nicastro
- Department of Biology, University of Fribourg, Chemin du Musée, Fribourg, Switzerland
| | | | - Sophie Grziwa
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Zilei Chen
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Rainer Kurre
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
| | - Jacob Piehler
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
- Department of Biology/Chemistry, Biophysics Section, Osnabrück University, Osnabrück, Germany
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, Chemin du Musée, Fribourg, Switzerland
| | - Florian Fröhlich
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
- Department of Biology/Chemistry, Molecular Membrane Biology Section, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
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15
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Abbas M, Fan YH, Shi XK, Gao L, Wang YL, Li T, Cooper AMW, Silver K, Zhu KY, Zhang JZ. Identification of Rab family genes and functional analyses of LmRab5 and LmRab11A in the development and RNA interference of Locusta migratoria. INSECT SCIENCE 2022; 29:320-332. [PMID: 34347932 DOI: 10.1111/1744-7917.12921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/26/2021] [Accepted: 03/13/2021] [Indexed: 06/13/2023]
Abstract
Rab proteins constitute the largest family of small GTPases, which play pivotal roles in intracellular membrane trafficking in all eukaryotes. A number of Rab genes have been identified in eukaryotes; however, very little information about these genes has been reported in insects. In the current study, for the first time we identified and characterized 27 Rab family genes from Locusta migratoria. Phylogenetic analysis and comparison of domain architecture indicated that Rab family genes are highly conserved among insect species. Tissue-dependent expression profiles indicated that expression of Rab genes was highest in the ovary, except for LmRab3, which was most highly expressed in hemolymph. The biological function of each Rab gene was investigated using RNA interference (RNAi). Double-stranded RNA targeting each Rab gene was injected into the hemocoel of nymphs and revealed that suppression of two Rab genes (LmRab5 and LmRab11A) caused 100% mortality. In addition, nymphs injected with dsLmRab5 exhibited severe phenotypic defects in the gastric caeca and midgut, while dsLmRab11A arrested the molting process. We then applied the RNAi of RNAi technique to test if silencing either of these two genes would affect the suppression of the lethal giant larvae (LmLgl) reporter gene and found that suppression of LmRab5 diminished the RNAi efficiency of LmLgl, whereas suppression of LmRab11A enhanced RNAi efficiency of LmLgl. These results indicate that Rab genes contribute differently to RNAi efficiency in different tissues. Our study provides a foundation for further functional investigations of Rab genes and their contributions to RNAi efficiency in L. migratoria.
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Affiliation(s)
- Mureed Abbas
- Institute of Applied Biology, Shanxi University, Taiyuan, China
| | - Yun-He Fan
- Institute of Applied Biology, Shanxi University, Taiyuan, China
- College of Life Science, Shanxi University, Taiyuan, China
| | - Xue-Kai Shi
- Institute of Applied Biology, Shanxi University, Taiyuan, China
- College of Life Science, Shanxi University, Taiyuan, China
| | - Lu Gao
- Institute of Applied Biology, Shanxi University, Taiyuan, China
- College of Life Science, Shanxi University, Taiyuan, China
| | - Yan-Li Wang
- Institute of Applied Biology, Shanxi University, Taiyuan, China
| | - Tao Li
- Institute of Applied Biology, Shanxi University, Taiyuan, China
| | | | - Kristopher Silver
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
| | - Kun Yan Zhu
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
| | - Jian-Zhen Zhang
- Institute of Applied Biology, Shanxi University, Taiyuan, China
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16
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Duarte PV, Hardenberg R, Mari M, Walter S, Reggiori F, Fröhlich F, Montoro AG, Ungermann C. The yeast LYST homolog Bph1 is a Rab5 effector and prevents Atg8 lipidation at endosomes. J Cell Sci 2022; 135:274866. [PMID: 35343566 DOI: 10.1242/jcs.259421] [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: 09/30/2021] [Accepted: 03/18/2022] [Indexed: 01/18/2023] Open
Abstract
Lysosomes mediate degradation of macromolecules to their precursors for their cellular recycling. Additionally, lysosome-related organelles mediate cell type-specific functions. The Chédiak-Higashi syndrome is an autosomal, recessive disease, in which loss of the protein LYST causes defects in lysosomes and lysosome-related organelles. The molecular function of LYST, however, is largely unknown. Here, we dissected the function of the yeast LYST homolog, Bph1. We show that Bph1 is an endosomal protein, and an effector of the minor Rab5 isoform Ypt52. Strikingly, the bph1▵ mutant has lipidated Atg8 on their endosomes, which is sorted via late endosomes into the vacuole lumen under non-autophagy inducing conditions. In agreement, proteomics of bph1▵ vacuoles reveal an accumulation of Atg8, reduced flux via selective autophagy, and defective endocytosis. Additionally, bph1▵ cells have reduced autophagic flux under starvation conditions. Our observations suggest that Bph1 is a novel Rab5 effector that maintains endosomal functioning. When lost, Atg8 is lipidated at endosomes even during normal growth and ends up in the vacuole lumen. Thus, our results contribute to the understanding of the role of LYST-related proteins and associated diseases.
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Affiliation(s)
- Prado Vargas Duarte
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Ralph Hardenberg
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Muriel Mari
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Stefan Walter
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Florian Fröhlich
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany.,Osnabrück University, Department of Biology/Chemistry, Molecular Membrane Biology section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Ayelén González Montoro
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany.,Osnabrück University, Department of Biology/Chemistry, Cellular Communication Laboratory, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Christian Ungermann
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany.,Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany
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17
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Kumar R, Francis V, Kulasekaran G, Khan M, Armstrong GAB, McPherson PS. A cell-based GEF assay reveals new substrates for DENN domains and a role for DENND2B in primary ciliogenesis. SCIENCE ADVANCES 2022; 8:eabk3088. [PMID: 35196081 PMCID: PMC8865772 DOI: 10.1126/sciadv.abk3088] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 12/30/2021] [Indexed: 06/14/2023]
Abstract
Primary cilia are sensory antennae crucial for cell and organism development, and defects in their biogenesis cause ciliopathies. Ciliogenesis involves membrane trafficking mediated by small guanosine triphosphatases (GTPases) including Rabs, molecular switches activated by guanine nucleotide exchange factors (GEFs). The largest family of Rab GEFs is the DENN domain-bearing proteins. Here, we screen all 60 Rabs against two major DENN domain families using a cellular GEF assay, uncovering 19 novel DENN/Rab pairs. The screen reveals Rab10 as a substrate for DENND2B, a protein previously implicated in cancer and severe mental retardation. Through activation of Rab10, DENND2B represses the formation of primary cilia. Through a second pathway, DENND2B functions as a GEF for RhoA to control the length of primary cilia. This work thus identifies an unexpected diversity in DENN domain-mediated activation of Rabs, a previously unidentified non-Rab substrate for a DENN domain, and a new regulatory protein in primary ciliogenesis.
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18
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Perica T, Mathy CJP, Xu J, Jang GM, Zhang Y, Kaake R, Ollikainen N, Braberg H, Swaney DL, Lambright DG, Kelly MJS, Krogan NJ, Kortemme T. Systems-level effects of allosteric perturbations to a model molecular switch. Nature 2021; 599:152-157. [PMID: 34646016 PMCID: PMC8571063 DOI: 10.1038/s41586-021-03982-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 09/01/2021] [Indexed: 11/10/2022]
Abstract
Molecular switch proteins whose cycling between states is controlled by opposing regulators1,2 are central to biological signal transduction. As switch proteins function within highly connected interaction networks3, the fundamental question arises of how functional specificity is achieved when different processes share common regulators. Here we show that functional specificity of the small GTPase switch protein Gsp1 in Saccharomyces cerevisiae (the homologue of the human protein RAN)4 is linked to differential sensitivity of biological processes to different kinetics of the Gsp1 (RAN) switch cycle. We make 55 targeted point mutations to individual protein interaction interfaces of Gsp1 (RAN) and show through quantitative genetic5 and physical interaction mapping that Gsp1 (RAN) interface perturbations have widespread cellular consequences. Contrary to expectation, the cellular effects of the interface mutations group by their biophysical effects on kinetic parameters of the GTPase switch cycle and not by the targeted interfaces. Instead, we show that interface mutations allosterically tune the GTPase cycle kinetics. These results suggest a model in which protein partner binding, or post-translational modifications at distal sites, could act as allosteric regulators of GTPase switching. Similar mechanisms may underlie regulation by other GTPases, and other biological switches. Furthermore, our integrative platform to determine the quantitative consequences of molecular perturbations may help to explain the effects of disease mutations that target central molecular switches.
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Affiliation(s)
- Tina Perica
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA,Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA,European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK,These authors contributed equally
| | - Christopher J. P. Mathy
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA,Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA,The UC Berkeley-UCSF Graduate Program in Bioengineering, University of California San Francisco, San Francisco, CA, USA,These authors contributed equally
| | - Jiewei Xu
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA,The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Gwendolyn M. Jang
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA,The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Yang Zhang
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA,Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA
| | - Robyn Kaake
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA,The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Noah Ollikainen
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA,Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA,Graduate Program in Bioinformatics, University of California San Francisco, San Francisco, California, United States of America
| | - Hannes Braberg
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA,The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Danielle L. Swaney
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA,The J. David Gladstone Institutes, San Francisco, CA, USA
| | - David G. Lambright
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Mark J. S. Kelly
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Nevan J. Krogan
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA,The J. David Gladstone Institutes, San Francisco, CA, USA,Correspondence and Requests for Materials should be addressed to: Tanja Kortemme () and Nevan Krogan ()
| | - Tanja Kortemme
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA. .,Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, CA, USA. .,The UC Berkeley-UCSF Graduate Program in Bioengineering, University of California San Francisco, San Francisco, CA, USA. .,Graduate Program in Bioinformatics, University of California San Francisco, San Francisco, California, USA. .,Chan Zuckerberg Biohub, San Francisco, CA, USA.
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19
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Huang S, Lai X, Yang L, Ye F, Huang C, Qiu Y, Lin S, Pu L, Wang Z, Huang W. Asporin Promotes TGF-β-induced Lung Myofibroblast Differentiation by Facilitating Rab11-dependent Recycling of TβRI. Am J Respir Cell Mol Biol 2021; 66:158-170. [PMID: 34705621 DOI: 10.1165/rcmb.2021-0257oc] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive fibrotic lung disease with high mortality and morbidity. Asporin (ASPN), a member of the small leucine-rich proteoglycan (SLRP) family, plays crucial roles in tissue injury and regeneration. However, the precise pathophysiological role of ASPN and its molecular mechanisms in IPF remain unknown. We sought to investigate the role of ASPN during the development of pulmonary fibrosis and the therapeutic potential of targeting ASPN-related signaling pathways. In our study, three microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database, and differentially expressed genes (DEGs) were screened out by bioinformatic analysis. Hub genes were selected from the protein-protein interaction network. ASPN was examined in lung tissues from pulmonary fibrosis mouse models and the role of ASPN in TGF-β/Smad signaling was determined by transfection with ASPN shRNA vectors in vitro. Biotinylation assays were conducted to measure plasma membrane TβRI and TβRI recycling after ASPN knockdown. The results showed ASPN expression was increased in the lungs of pulmonary fibrosis mouse models, and ASPN was primarily localized in α-SMA+ myofibroblasts. In vitro experiments proved that ASPN knockdown inhibited TGF-β/Smad signaling and myofibroblast differentiation by regulating the stability of TβRI. Further molecular mechanisms revealed that ASPN knockdown inhibited TGF-β/Smad signaling by suppressing recycling of TβRI to the cell surface in a Rab11-dependent manner and facilitated lysosome-mediated degradation of TβRI. In conclusion, our findings provide important evidence for the use of ASPN as a novel pharmacological target for treating pulmonary fibrosis.
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Affiliation(s)
- Shaojie Huang
- Sun Yat-sen University First Affiliated Hospital, 71068, Department of Cardiac Surgery, Guangzhou, China
| | - Xiaofan Lai
- Sun Yat-sen University First Affiliated Hospital, 71068, Department of Anesthesiology, Guangzhou, China
| | - Lu Yang
- Sun Yat-sen University First Affiliated Hospital, 71068, Department of Anesthesiology, Guangzhou, China
| | - Fang Ye
- Sun Yat-sen University First Affiliated Hospital, 71068, Department of Anesthesiology, Guangzhou, China
| | - Chanyan Huang
- Sun Yat-sen University First Affiliated Hospital, 71068, Department of Anesthesiology, Guangzhou, China
| | - Yuan Qiu
- Sun Yat-Sen University, 26469, Center for stem cell biology and tissue engineering, Guangzhou, China
| | - Sijia Lin
- Sun Yat-Sen University, 26469, Guangzhou, China
| | - Lvya Pu
- Sun Yat-Sen University, 26469, Guangzhou, China
| | - Zhongxing Wang
- Sun Yat-sen University First Affiliated Hospital, 71068, Department of Anesthesiology, Guangzhou, China
| | - Wenqi Huang
- Sun Yat-sen University First Affiliated Hospital, 71068, Department of Anesthesiology, Guangzhou, China;
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20
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Borchers AC, Langemeyer L, Ungermann C. Who's in control? Principles of Rab GTPase activation in endolysosomal membrane trafficking and beyond. J Cell Biol 2021; 220:212549. [PMID: 34383013 PMCID: PMC8366711 DOI: 10.1083/jcb.202105120] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/08/2021] [Accepted: 07/08/2021] [Indexed: 12/12/2022] Open
Abstract
The eukaryotic endomembrane system consists of multiple interconnected organelles. Rab GTPases are organelle-specific markers that give identity to these membranes by recruiting transport and trafficking proteins. During transport processes or along organelle maturation, one Rab is replaced by another, a process termed Rab cascade, which requires at its center a Rab-specific guanine nucleotide exchange factor (GEF). The endolysosomal system serves here as a prime example for a Rab cascade. Along with endosomal maturation, the endosomal Rab5 recruits and activates the Rab7-specific GEF Mon1-Ccz1, resulting in Rab7 activation on endosomes and subsequent fusion of endosomes with lysosomes. In this review, we focus on the current idea of Mon1-Ccz1 recruitment and activation in the endolysosomal and autophagic pathway. We compare identified principles to other GTPase cascades on endomembranes, highlight the importance of regulation, and evaluate in this context the strength and relevance of recent developments in in vitro analyses to understand the underlying foundation of organelle biogenesis and maturation.
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Affiliation(s)
- Ann-Christin Borchers
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
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21
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Shan MM, Sun SC. The multiple roles of RAB GTPases in female and male meiosis. Hum Reprod Update 2021; 27:1013-1029. [PMID: 34227671 DOI: 10.1093/humupd/dmab019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/06/2021] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND RAB GTPases constitute the largest family of small GTPases and are found in all eukaryotes. RAB GTPases regulate components of the endomembrane system, the nucleus and the plasma membrane, and are involved in intracellular actin/tubulin-dependent vesicle movement, membrane fusion and cell growth in mitosis. OBJECTIVE AND RATIONALE RAB GTPases play multiple critical roles during both female and male meiosis. This review summarizes the progress made in our understanding of the role of RAB GTPases in female and male meiosis in different species. We also discuss the potential relationship between RAB GTPases and oocyte/sperm quality, which may help in understanding the mechanisms underlying oogenesis and spermatogenesis and potential genetic causes of infertility. SEARCH METHODS The PubMed database was searched for articles published between 1991 and 2020 using the following terms: 'RAB', 'RAB oocyte', 'RAB sperm' and 'RAB meiosis'. OUTCOMES An analysis of 126 relevant articles indicated that RAB GTPases are present in all eukaryotes, and ten subfamilies (almost 70 members) are expressed in human cells. The roles of 25 RAB proteins and orthologues in female meiosis and 12 in male meiosis have been reported. RAB proteins are essential for the accurate continuity of genetic material, successful fertilization and the normal growth of offspring. Distinct and crucial functions of RAB GTPases in meiosis have been reported. In oocytes, RAB GTPases are involved in spindle organization, kinetochore-microtubule attachment, chromosome alignment, actin filament-mediated spindle migration, cytokinesis, cell cycle and oocyte-embryo transition. RAB GTPases function in mitochondrial processes and Golgi-mediated vesicular transport during female meiosis, and are critical for cortical granule transport during fertilization and oocyte-embryo transition. In sperm, RAB GTPases are vital for cytoskeletal organization and successful cytokinesis, and are associated with Golgi-mediated acrosome formation, membrane trafficking and morphological changes of sperm cells, as well as the exocytosis-related acrosome reaction and zona reaction during fertilization. WIDER IMPLICATIONS Abnormal expression of RAB GTPases disrupts intracellular systems, which may induce diverse diseases. The roles of RAB proteins in female and male reproductive systems, thus, need to be considered. The mechanisms underlying the function of RAB GTPases and the binding specificity of their effectors during oogenesis, spermatogenesis and fertilization remain to be studied. This review should contribute to our understanding of the molecular mechanisms of oogenesis and spermatogenesis and potential genetic causes of infertility.
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Affiliation(s)
- Meng-Meng Shan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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22
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Arias-Hervert ER, Xu N, Njus M, Murphy GG, Hou Y, Williams JA, Lentz SI, Ernst SA, Stuenkel EL. Actions of Rab27B-GTPase on mammalian central excitatory synaptic transmission. Physiol Rep 2021; 8:e14428. [PMID: 32358861 PMCID: PMC7195558 DOI: 10.14814/phy2.14428] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 12/20/2022] Open
Abstract
Members of the Rab3 gene family are considered central to membrane trafficking of synaptic vesicles at mammalian central excitatory synapses. Recent evidence, however, indicates that the Rab27B-GTPase, which is highly homologous to the Rab3 family, is also enriched on SV membranes and co-localize with Rab3A and Synaptotagmin at presynaptic terminals. While functional roles of Rab3A have been well-established, little functional information exists on the role of Rab27B in synaptic transmission. Here we report on functional effects of Rab27B at SC-CA1 and DG-MF hippocampal synapses. The data establish distinct functional actions of Rab27B and demonstrate functions of Rab27B that differ between SC-CA1 and DG-MF synapses. Rab27B knockout reduced frequency facilitation compared to wild-type (WT) controls at the DG/MF-CA3 synaptic region, while increasing facilitation at the SC-CA1 synaptic region. Remarkably, Rab27B KO resulted in a complete elimination of LTP at the MF-CA3 synapse with no effect at the SC-CA1 synapse. These actions are similar to those previously reported for Rab3A KO. Specificity of action on LTP to Rab27B was confirmed as LTP was rescued in response to lentiviral infection and expression of human Rab27B, but not to GFP, in the DG in the Rab27B KO mice. Notably, the effect of Rab27B KO on MF-CA3 LTP occurred in spite of continued expression of Rab3A in the Rab27B KO. Overall, the results provide a novel perspective in suggesting that Rab27B and Rab3A act synergistically, perhaps via sequential effector recruitment or signaling for presynaptic LTP expression in this hippocampal synaptic region.
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Affiliation(s)
- Erwin R Arias-Hervert
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
| | - Nicole Xu
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
| | - Meredith Njus
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
| | - Geoff G Murphy
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA.,Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Yanan Hou
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
| | - John A Williams
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA.,Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Stephen I Lentz
- Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Stephen A Ernst
- Cell & Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Edward L Stuenkel
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, USA
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23
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Galindo A, Planelles-Herrero VJ, Degliesposti G, Munro S. Cryo-EM structure of metazoan TRAPPIII, the multi-subunit complex that activates the GTPase Rab1. EMBO J 2021; 40:e107608. [PMID: 34018214 PMCID: PMC8204870 DOI: 10.15252/embj.2020107608] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/30/2021] [Accepted: 04/11/2021] [Indexed: 12/19/2022] Open
Abstract
The TRAPP complexes are nucleotide exchange factors that play essential roles in membrane traffic and autophagy. TRAPPII activates Rab11, and TRAPPIII activates Rab1, with the two complexes sharing a core of small subunits that affect nucleotide exchange but being distinguished by specific large subunits that are essential for activity in vivo. Crystal structures of core subunits have revealed the mechanism of Rab activation, but how the core and the large subunits assemble to form the complexes is unknown. We report a cryo‐EM structure of the entire Drosophila TRAPPIII complex. The TRAPPIII‐specific subunits TRAPPC8 and TRAPPC11 hold the catalytic core like a pair of tongs, with TRAPPC12 and TRAPPC13 positioned at the joint between them. TRAPPC2 and TRAPPC2L link the core to the two large arms, with the interfaces containing residues affected by disease‐causing mutations. The TRAPPC8 arm is positioned such that it would contact Rab1 that is bound to the core, indicating how the arm could determine the specificity of the complex. A lower resolution structure of TRAPPII shows a similar architecture and suggests that the TRAPP complexes evolved from a single ur‐TRAPP.
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Affiliation(s)
| | | | | | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, UK
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24
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Simvastatin accelerated motoneurons death in SOD1 G93A mice through inhibiting Rab7-mediated maturation of late autophagic vacuoles. Cell Death Dis 2021; 12:392. [PMID: 33846297 PMCID: PMC8041862 DOI: 10.1038/s41419-021-03669-w] [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: 09/11/2020] [Accepted: 03/25/2021] [Indexed: 02/08/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease caused by motoneuron loss, for which there is currently no effective treatment. Statins, as inhibitors of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, are used as drugs for treatment for a variety of disease such as ischemic diseases, neurodegenerative diseases, cancer, and inflammation. However, our previous evidence has demonstrated that simvastatin leads to cytotoxicity in NSC34-hSOD1G93A cells by aggravating the impairment of autophagic flux, but the role of simvastatin in ALS model remains elusive. In present study, we reported that after simvastatin treatment, SOD1G93A mice showed early onset of the disease phenotype and shortened life span, with aggravated autophagic flux impairment and increased aggregation of SOD1 protein in spinal cord motoneurons (MNs) of SOD1G93A mice. In addition, simvastatin repressed the ability of Rab7 localization on the membrane by inhibiting isoprenoid synthesis, leading to impaired late stage of autophagic flux rather than initiation. This study suggested that simvastatin significantly worsened impairment of late autophagic flux, resulting in massive MNs death in spinal cord and accelerated disease progression of SOD1G93A mice. Together, these findings might imply a potential risk of clinic application of statins in ALS.
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25
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Pinar M, Peñalva MA. The fungal RABOME: RAB GTPases acting in the endocytic and exocytic pathways of Aspergillus nidulans (with excursions to other filamentous fungi). Mol Microbiol 2021; 116:53-70. [PMID: 33724562 DOI: 10.1111/mmi.14716] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/04/2021] [Accepted: 03/11/2021] [Indexed: 10/21/2022]
Abstract
RAB GTPases are major determinants of membrane identity that have been exploited as highly specific reporters to study intracellular traffic in vivo. A score of fungal papers have considered individual RABs, but systematic, integrated studies on the localization and physiological role of these regulators and their effectors have been performed only with Aspergillus nidulans. These studies have influenced the intracellular trafficking field beyond fungal specialists, leading to findings such as the maturation of trans-Golgi (TGN) cisternae into post-Golgi RAB11 secretory vesicles, the concept that these RAB11 secretory carriers are loaded with three molecular nanomotors, the understanding of the role of endocytic recycling mediated by RAB6 and RAB11 in determining the hyphal mode of life, the discovery that early endosome maturation and the ESCRT pathway are essential, the identification of specific adaptors of dynein-dynactin to RAB5 endosomes, the exquisite dependence that autophagy displays on RAB1 activity, the role of TRAPPII as a GEF for RAB11, or the conclusion that the RAB1-to-RAB11 transition is not mediated by TRAPP maturation. A remarkable finding was that the A. nidulans Spitzenkörper contains four RABs: RAB11, Sec4, RAB6, and RAB1. How these RABs cooperate during exocytosis represents an as yet outstanding question.
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Affiliation(s)
- Mario Pinar
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
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26
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Machado ER, Annunziata I, van de Vlekkert D, Grosveld GC, d’Azzo A. Lysosomes and Cancer Progression: A Malignant Liaison. Front Cell Dev Biol 2021; 9:642494. [PMID: 33718382 PMCID: PMC7952443 DOI: 10.3389/fcell.2021.642494] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/08/2021] [Indexed: 01/04/2023] Open
Abstract
During primary tumorigenesis isolated cancer cells may undergo genetic or epigenetic changes that render them responsive to additional intrinsic or extrinsic cues, so that they enter a transitional state and eventually acquire an aggressive, metastatic phenotype. Among these changes is the alteration of the cell metabolic/catabolic machinery that creates the most permissive conditions for invasion, dissemination, and survival. The lysosomal system has emerged as a crucial player in this malignant transformation, making this system a potential therapeutic target in cancer. By virtue of their ubiquitous distribution in mammalian cells, their multifaced activities that control catabolic and anabolic processes, and their interplay with other organelles and the plasma membrane (PM), lysosomes function as platforms for inter- and intracellular communication. This is due to their capacity to adapt and sense nutrient availability, to spatially segregate specific functions depending on their position, to fuse with other compartments and with the PM, and to engage in membrane contact sites (MCS) with other organelles. Here we review the latest advances in our understanding of the role of the lysosomal system in cancer progression. We focus on how changes in lysosomal nutrient sensing, as well as lysosomal positioning, exocytosis, and fusion perturb the communication between tumor cells themselves and between tumor cells and their microenvironment. Finally, we describe the potential impact of MCS between lysosomes and other organelles in propelling cancer growth and spread.
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Affiliation(s)
- Eda R. Machado
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | - Ida Annunziata
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | | | - Gerard C. Grosveld
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | - Alessandra d’Azzo
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN, United States
- Department of Anatomy and Neurobiology, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, United States
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27
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Ma CIJ, Brill JA. Endosomal Rab GTPases regulate secretory granule maturation in Drosophila larval salivary glands. Commun Integr Biol 2021; 14:15-20. [PMID: 33628358 PMCID: PMC7889263 DOI: 10.1080/19420889.2021.1874663] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Secretory granules (SGs) are organelles responsible for regulated exocytosis of biologically active molecules in professional secretory cells. Maturation of SGs is a crucial process in which cargoes of SGs are processed and activated, allowing them to exert their function upon secretion. Nonetheless, the intracellular trafficking pathways required for SG maturation are not well defined. We recently performed an RNA interference (RNAi) screen in Drosophila larval salivary glands to identify trafficking components needed for SG maturation. From the screen, we identified several Rab GTPases (Rabs) that affect SG maturation. Expression of constitutively active (CA) and dominant-negative (DN) forms narrowed down the Rabs important for this process to Rab5, Rab9 and Rab11. However, none of these Rabs localizes to the limiting membrane of SGs. In contrast, examination of endogenously YFP-tagged Rabs (YRabs) in larval salivary glands revealed that YRab1 and YRab6 localize to the limiting membrane of immature SGs (iSGs) and SGs. These findings provide new insights into how Rab GTPases contribute to the process of SG maturation.
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Affiliation(s)
- Cheng-I Jonathan Ma
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Medical Sciences Building, Toronto, ON, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Medical Sciences Building, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Medical Sciences Building, Toronto, ON, Canada
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28
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Taku I, Hirai T, Makiuchi T, Shinzawa N, Iwanaga S, Annoura T, Nagamune K, Nozaki T, Saito-Nakano Y. Rab5b-Associated Arf1 GTPase Regulates Export of N-Myristoylated Adenylate Kinase 2 From the Endoplasmic Reticulum in Plasmodium falciparum. Front Cell Infect Microbiol 2021; 10:610200. [PMID: 33604307 PMCID: PMC7884776 DOI: 10.3389/fcimb.2020.610200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/17/2020] [Indexed: 01/08/2023] Open
Abstract
Plasmodium falciparum extensively remodels human erythrocytes by exporting hundreds of parasite proteins. This remodeling is closely linked to the Plasmodium virulence-related functions and immune evasion. The N-terminal export signal named PEXEL (Plasmodium export element) was identified to be important for the export of proteins beyond the PVM, however, the issue of how these PEXEL-positive proteins are transported and regulated by Rab GTPases from the endoplasmic reticulum (ER) to the cell surface has remained poorly understood. Previously, we identified new aspects of the trafficking of N-myristoylated adenylate kinase 2 (PfAK2), which lacks the PEXEL motif and is regulated by the PfRab5b GTPase. Overexpression of PfRab5b suppressed the transport of PfAK2 to the parasitophorous vacuole membrane and PfAK2 was accumulated in the punctate compartment within the parasite. Here, we report the identification of PfRab5b associated proteins and dissect the pathway regulated by PfRab5b. We isolated two membrane trafficking GTPases PfArf1 and PfRab1b by coimmunoprecipitation with PfRab5b and via mass analysis. PfArf1 and PfRab1b are both colocalized with PfRab5b adjacent to the ER in the early erythrocytic stage. A super-resolution microgram of the indirect immunofluorescence assay using PfArf1 or PfRab1b- expressing parasites revealed that PfArf1 and PfRab1b are localized to different ER subdomains. We used a genetic approach to expresses an active or inactive mutant of PfArf1 that specifically inhibited the trafficking of PfAK2 to the parasitophorous vacuole membrane. While expression of PfRab1b mutants did not affect in the PfAK2 transport. In contrast, the export of the PEXEL-positive protein Rifin was decreased by the expression of the inactive mutant of PfRab1b or PfArf1. These data indicate that the transport of PfAK2 and Rifin were recognized at the different ER subdomain by the two independent GTPases: PfAK2 is sorted by PfArf1 into the pathway for the PV, and the export of Rifin might be sequentially regulated by PfArf1 and PfRab1b.
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Affiliation(s)
- Izumi Taku
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Tomohiro Hirai
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Takashi Makiuchi
- Department of Parasitology, Tokai University School of Medicine, Isehara, Japan
| | - Naoaki Shinzawa
- Department of Environmental Parasitology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shiroh Iwanaga
- Department of Environmental Parasitology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takeshi Annoura
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kisaburo Nagamune
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Tomoyoshi Nozaki
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
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29
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Leyland B, Zarka A, Didi-Cohen S, Boussiba S, Khozin-Goldberg I. High Resolution Proteome of Lipid Droplets Isolated from the Pennate Diatom Phaeodactylum tricornutum (Bacillariophyceae) Strain pt4 provides mechanistic insights into complex intracellular coordination during nitrogen deprivation. JOURNAL OF PHYCOLOGY 2020; 56:1642-1663. [PMID: 32779202 DOI: 10.1111/jpy.13063] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/14/2020] [Accepted: 07/12/2020] [Indexed: 05/08/2023]
Abstract
Lipid droplets (LDs) are an organelle conserved amongst all eukaryotes, consisting of a neutral lipid core surrounded by a polar lipid monolayer. Many species of microalgae accumulate LDs in response to stress conditions, such as nitrogen starvation. Here, we report the isolation and proteomic profiling of LD proteins from the model oleaginous pennate diatom Phaeodactylum tricornutum, strain Pt4 (UTEX 646). We also provide a quantitative description of LD morphological ontogeny, and fatty acid content. Novel cell disruption and LD isolation methods, combined with suspension-trapping and nanoflow liquid chromatography coupled to high resolution mass spectrometry, yielded an unprecedented number of LD proteins. Predictive annotation of the LD proteome suggests a broad assemblage of proteins with diverse functions, including lipid metabolism and vesicle trafficking, as well as ribosomal and proteasomal machinery. These proteins provide mechanistic insights into LD processes, and evidence for interactions between LDs and other organelles. We identify for the first time several key steps in diatom LD-associated triacylglycerol biosynthesis. Bioinformatic analyses of the LD proteome suggests multiple protein targeting mechanisms, including amphipathic helices, post-translational modifications, and translocation machinery. This work corroborates recent findings from other strains of P. tricornutum, other diatoms, and other eukaryotic organisms, suggesting that the fundamental proteins orchestrating LDs are conserved, and represent an ancient component of the eukaryotic endomembrane system. We postulate a comprehensive model of nitrogen starvation-induced diatom LDs on a molecular scale, and provide a wealth of candidates for metabolic engineering, with the potential to eventually customize LD contents.
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Affiliation(s)
- Ben Leyland
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Aliza Zarka
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Shoshana Didi-Cohen
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Sammy Boussiba
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Inna Khozin-Goldberg
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
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30
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Gao J, Kurre R, Rose J, Walter S, Fröhlich F, Piehler J, Reggiori F, Ungermann C. Function of the SNARE Ykt6 on autophagosomes requires the Dsl1 complex and the Atg1 kinase complex. EMBO Rep 2020; 21:e50733. [PMID: 33025734 PMCID: PMC7726795 DOI: 10.15252/embr.202050733] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 09/04/2020] [Accepted: 09/14/2020] [Indexed: 12/11/2022] Open
Abstract
The mechanism and regulation of fusion between autophagosomes and lysosomes/vacuoles are still only partially understood in both yeast and mammals. In yeast, this fusion step requires SNARE proteins, the homotypic vacuole fusion and protein sorting (HOPS) tethering complex, the RAB7 GTPase Ypt7, and its guanine nucleotide exchange factor (GEF) Mon1‐Ccz1. We and others recently identified Ykt6 as the autophagosomal SNARE protein. However, it has not been resolved when and how lipid‐anchored Ykt6 is recruited onto autophagosomes. Here, we show that Ykt6 is recruited at an early stage of the formation of these carriers through a mechanism that depends on endoplasmic reticulum (ER)‐resident Dsl1 complex and COPII‐coated vesicles. Importantly, Ykt6 activity on autophagosomes is regulated by the Atg1 kinase complex, which inhibits Ykt6 through direct phosphorylation. Thus, our findings indicate that the Ykt6 pool on autophagosomal membranes is kept inactive by Atg1 phosphorylation, and once an autophagosome is ready to fuse with vacuole, Ykt6 dephosphorylation allows its engagement in the fusion event.
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Affiliation(s)
- Jieqiong Gao
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Rainer Kurre
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany
| | - Jaqueline Rose
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Florian Fröhlich
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
| | - Jacob Piehler
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany.,Department of Biology/Chemistry, Biophysics Section, University of Osnabrück, Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
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31
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Koch D. Homo-Oligomerisation in Signal Transduction: Dynamics, Homeostasis, Ultrasensitivity, Bistability. J Theor Biol 2020; 499:110305. [PMID: 32437710 PMCID: PMC7327509 DOI: 10.1016/j.jtbi.2020.110305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/26/2020] [Accepted: 04/27/2020] [Indexed: 01/08/2023]
Abstract
Homo-oligomerisation of proteins is a ubiquitous phenomenon whose exact role remains unclear in many cases. To identify novel functions, this paper provides an exploration of general dynamical mathematical models of homo-oligomerisation. Simulation and analysis of these models show that homo-oligomerisation on its own allows for a remarkable variety of complex dynamic and steady state regulatory behaviour such as transient overshoots or homeostatic control of monomer concentration. If post-translational modifications are considered, however, conventional mass action kinetics lead to thermodynamic inconsistencies due to asymmetric combinatorial expansion of reaction routes. Introducing a conservation principle to balance rate equations re-establishes thermodynamic consistency. Using such balanced models it is shown that oligomerisation can lead to bistability by enabling pseudo-multisite modification and kinetic pseudo-cooperativity via multi-enzyme regulation, thereby constituting a novel motif for bistable modification reactions. Due to these potential signal processing capabilities, homo-oligomerisation could play far more versatile roles in signal transduction than previously appreciated.
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Affiliation(s)
- Daniel Koch
- Randall Centre for Cell & Molecular Biophysics King's College London, London SE1 1UL, United Kingdom.
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32
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Rivero-Ríos P, Romo-Lozano M, Fernández B, Fdez E, Hilfiker S. Distinct Roles for RAB10 and RAB29 in Pathogenic LRRK2-Mediated Endolysosomal Trafficking Alterations. Cells 2020; 9:cells9071719. [PMID: 32709066 PMCID: PMC7407826 DOI: 10.3390/cells9071719] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/12/2020] [Accepted: 07/13/2020] [Indexed: 12/14/2022] Open
Abstract
Summary Statement Pathogenic LRRK2 expression causes endolysosomal trafficking alterations by impairing RAB10 function, and these alterations are rescued by RAB29 independent of its Golgi localization. Abstract Mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) cause familial Parkinson’s disease, and sequence variations are associated with the sporadic form of the disease. LRRK2 phosphorylates a subset of RAB proteins implicated in secretory and recycling trafficking pathways, including RAB8A and RAB10. Another RAB protein, RAB29, has been reported to recruit LRRK2 to the Golgi, where it stimulates its kinase activity. Our previous studies revealed that G2019S LRRK2 expression or knockdown of RAB8A deregulate epidermal growth factor receptor (EGFR) trafficking, with a concomitant accumulation of the receptor in a RAB4-positive recycling compartment. Here, we show that the G2019S LRRK2-mediated EGFR deficits are mimicked by knockdown of RAB10 and rescued by expression of active RAB10. By contrast, RAB29 knockdown is without effect, but expression of RAB29 also rescues the pathogenic LRRK2-mediated trafficking deficits independently of Golgi integrity. Our data suggest that G2019S LRRK2 deregulates endolysosomal trafficking by impairing the function of RAB8A and RAB10, while RAB29 positively modulates non-Golgi-related trafficking events impaired by pathogenic LRRK2.
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Affiliation(s)
- Pilar Rivero-Ríos
- Institute of Parasitology and Biomedicine “López-Neyra”, Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain; (P.R.-R.); (M.R.-L.); (B.F.); (E.F.)
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Maria Romo-Lozano
- Institute of Parasitology and Biomedicine “López-Neyra”, Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain; (P.R.-R.); (M.R.-L.); (B.F.); (E.F.)
| | - Belén Fernández
- Institute of Parasitology and Biomedicine “López-Neyra”, Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain; (P.R.-R.); (M.R.-L.); (B.F.); (E.F.)
| | - Elena Fdez
- Institute of Parasitology and Biomedicine “López-Neyra”, Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain; (P.R.-R.); (M.R.-L.); (B.F.); (E.F.)
| | - Sabine Hilfiker
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
- Correspondence:
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33
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Wu Y, Zhi L, Zhao Y, Yang L, Cai F. Knockdown of circular RNA UBAP2 inhibits the malignant behaviours of esophageal squamous cell carcinoma by microRNA-422a/Rab10 axis. Clin Exp Pharmacol Physiol 2020; 47:1283-1290. [PMID: 32012318 DOI: 10.1111/1440-1681.13269] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 11/27/2019] [Accepted: 01/27/2020] [Indexed: 02/06/2023]
Abstract
Esophageal squamous cell carcinoma (ESCC) is a major type of esophageal cancer, accounting for about 90% of cases. Circular RNA UBAP2 (circUBAP2) is involved in the progression of several types of cancers. However, the role of circUBAP2 in ESCC remains unclear. In the present study, circUBAP2 expression was found to be upregulated in ESCC tumour tissues. Knockdown of circUBAP2 through infection with lentiviral vector encoding shRNA targeting circUBAP2 (sh-circUBAP2) inhibited the proliferation, migration and invasion of ESCC cells. In addition, circUBAP2 significantly promoted the proliferation, migration and invasion of ESCC cells. In vivo xenograft assay demonstrated that circUBAP2 downregulation suppressed the tumour growth of ESCC. Further mechanism investigations proved that circUBAP2 exerted its role via sponging microRNA (miR)-422a, and miR-422a directly targeted Rab10 in ESCC cells. These findings suggested that circUBAP2 acted as oncogene through regulating the miR-422a/Rab10 axis in ESCC.
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Affiliation(s)
- Yu Wu
- Department of Thoracic Surgery, Shaanxi People's Hospital, Xi'an, China
| | - Lingran Zhi
- Department of Pathology, Xi'an Fourth Hospital, Xi'an, China
| | - Ying Zhao
- Department of Pathology, Xi'an Fourth Hospital, Xi'an, China
| | - Lili Yang
- Department of Pathology, Xi'an Fourth Hospital, Xi'an, China
| | - Fengmei Cai
- Department of Pathology, Xi'an Fourth Hospital, Xi'an, China
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Rab11b-mediated integrin recycling promotes brain metastatic adaptation and outgrowth. Nat Commun 2020; 11:3017. [PMID: 32541798 PMCID: PMC7295786 DOI: 10.1038/s41467-020-16832-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 05/27/2020] [Indexed: 12/11/2022] Open
Abstract
Breast cancer brain metastases (BCBM) have a 5-20 year latency and account for 30% of mortality; however, mechanisms governing adaptation to the brain microenvironment remain poorly defined. We combine time-course RNA-sequencing of BCBM development with a Drosophila melanogaster genetic screen, and identify Rab11b as a functional mediator of metastatic adaptation. Proteomic analysis reveals that Rab11b controls the cell surface proteome, recycling proteins required for successful interaction with the microenvironment, including integrin β1. Rab11b-mediated control of integrin β1 surface expression allows efficient engagement with the brain ECM, activating mechanotransduction signaling to promote survival. Lipophilic statins prevent membrane association and activity of Rab11b, and we provide proof-of principle that these drugs prevent breast cancer adaptation to the brain microenvironment. Our results identify Rab11b-mediated recycling of integrin β1 as regulating BCBM, and suggest that the recycleome, recycling-based control of the cell surface proteome, is a previously unknown driver of metastatic adaptation and outgrowth.
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35
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A hypoxia-induced Rab pathway regulates embryo implantation by controlled trafficking of secretory granules. Proc Natl Acad Sci U S A 2020; 117:14532-14542. [PMID: 32513733 DOI: 10.1073/pnas.2000810117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Implantation is initiated when an embryo attaches to the uterine luminal epithelium and subsequently penetrates into the underlying stroma to firmly embed in the endometrium. These events are followed by the formation of an extensive vascular network in the stroma that supports embryonic growth and ensures successful implantation. Interestingly, in many mammalian species, these processes of early pregnancy occur in a hypoxic environment. However, the mechanisms underlying maternal adaptation to hypoxia during early pregnancy remain unclear. In this study, using a knockout mouse model, we show that the transcription factor hypoxia-inducible factor 2 alpha (Hif2α), which is induced in subluminal stromal cells at the time of implantation, plays a crucial role during early pregnancy. Indeed, when preimplantation endometrial stromal cells are exposed to hypoxic conditions in vitro, we observed a striking enhancement in HIF2α expression. Further studies revealed that HIF2α regulates the expression of several metabolic and protein trafficking factors, including RAB27B, at the onset of implantation. RAB27B is a member of the Rab family of GTPases that allows controlled release of secretory granules. These granules are involved in trafficking MMP-9 from the stroma to the epithelium to promote luminal epithelial remodeling during embryo invasion. As pregnancy progresses, the HIF2α-RAB27B pathway additionally mediates crosstalk between stromal and endothelial cells via VEGF granules, developing the vascular network critical for establishing pregnancy. Collectively, our study provides insights into the intercellular communication mechanisms that operate during adaptation to hypoxia, which is essential for embryo implantation and establishment of pregnancy.
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36
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Langemeyer L, Borchers AC, Herrmann E, Füllbrunn N, Han Y, Perz A, Auffarth K, Kümmel D, Ungermann C. A conserved and regulated mechanism drives endosomal Rab transition. eLife 2020; 9:56090. [PMID: 32391792 PMCID: PMC7239660 DOI: 10.7554/elife.56090] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 05/07/2020] [Indexed: 12/31/2022] Open
Abstract
Endosomes and lysosomes harbor Rab5 and Rab7 on their surface as key proteins involved in their identity, biogenesis, and fusion. Rab activation requires a guanine nucleotide exchange factor (GEF), which is Mon1-Ccz1 for Rab7. During endosome maturation, Rab5 is replaced by Rab7, though the underlying mechanism remains poorly understood. Here, we identify the molecular determinants for Rab conversion in vivo and in vitro, and reconstitute Rab7 activation with yeast and metazoan proteins. We show (i) that Mon1-Ccz1 is an effector of Rab5, (ii) that membrane-bound Rab5 is the key factor to directly promote Mon1-Ccz1 dependent Rab7 activation and Rab7-dependent membrane fusion, and (iii) that this process is regulated in yeast by the casein kinase Yck3, which phosphorylates Mon1 and blocks Rab5 binding. Our study thus uncovers the minimal feed-forward machinery of the endosomal Rab cascade and a novel regulatory mechanism controlling this pathway.
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Affiliation(s)
- Lars Langemeyer
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Ann-Christin Borchers
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Eric Herrmann
- University of Münster, Institute of Biochemistry, Münster, Germany
| | - Nadia Füllbrunn
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Yaping Han
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Angela Perz
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Kathrin Auffarth
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Daniel Kümmel
- University of Münster, Institute of Biochemistry, Münster, Germany
| | - Christian Ungermann
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany.,University of Osnabrück, Center of Cellular Nanoanalytics (CellNanOs), Osnabrück, Germany
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37
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Bezeljak U, Loya H, Kaczmarek B, Saunders TE, Loose M. Stochastic activation and bistability in a Rab GTPase regulatory network. Proc Natl Acad Sci U S A 2020; 117:6540-6549. [PMID: 32161136 PMCID: PMC7104049 DOI: 10.1073/pnas.1921027117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The eukaryotic endomembrane system is controlled by small GTPases of the Rab family, which are activated at defined times and locations in a switch-like manner. While this switch is well understood for an individual protein, how regulatory networks produce intracellular activity patterns is currently not known. Here, we combine in vitro reconstitution experiments with computational modeling to study a minimal Rab5 activation network. We find that the molecular interactions in this system give rise to a positive feedback and bistable collective switching of Rab5. Furthermore, we find that switching near the critical point is intrinsically stochastic and provide evidence that controlling the inactive population of Rab5 on the membrane can shape the network response. Notably, we demonstrate that collective switching can spread on the membrane surface as a traveling wave of Rab5 activation. Together, our findings reveal how biochemical signaling networks control vesicle trafficking pathways and how their nonequilibrium properties define the spatiotemporal organization of the cell.
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Affiliation(s)
- Urban Bezeljak
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Hrushikesh Loya
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Beata Kaczmarek
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Timothy E Saunders
- Mechanobiology Institute, National University of Singapore, Singapore 119077;
- Department of Biological Sciences, National University of Singapore, Singapore 119077
| | - Martin Loose
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria;
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38
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Extensive GTPase crosstalk regulates Golgi trafficking and maturation. Curr Opin Cell Biol 2020; 65:1-7. [PMID: 32143122 DOI: 10.1016/j.ceb.2020.01.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/23/2020] [Indexed: 12/12/2022]
Abstract
Virtually all transport events at the Golgi complex are regulated by Arf and Rab family GTPases. Recent work has advanced our knowledge regarding the mechanisms controlling GTPase activity, and it has become clear that GTPases do not act in isolation but rather function in complex networks of crosstalk and feedback. Together with earlier findings, these recent studies indicate that communication between GTPases, their regulatory proteins, effectors, and lipids plays a pivotal role in Golgi transport and cisternal maturation.
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39
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Voss L, Foster OK, Harper L, Morris C, Lavoy S, Brandt JN, Peloza K, Handa S, Maxfield A, Harp M, King B, Eichten V, Rambo FM, Hermann GJ. An ABCG Transporter Functions in Rab Localization and Lysosome-Related Organelle Biogenesis in Caenorhabditis elegans. Genetics 2020; 214:419-445. [PMID: 31848222 PMCID: PMC7017009 DOI: 10.1534/genetics.119.302900] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 12/11/2019] [Indexed: 12/20/2022] Open
Abstract
ABC transporters couple ATP hydrolysis to the transport of substrates across cellular membranes. This protein superfamily has diverse activities resulting from differences in their cargo and subcellular localization. Our work investigates the role of the ABCG family member WHT-2 in the biogenesis of gut granules, a Caenorhabditis elegans lysosome-related organelle. In addition to being required for the accumulation of birefringent material within gut granules, WHT-2 is necessary for the localization of gut granule proteins when trafficking pathways to this organelle are partially disrupted. The role of WHT-2 in gut granule protein targeting is likely linked to its function in Rab GTPase localization. We show that WHT-2 promotes the gut granule association of the Rab32 family member GLO-1 and the endolysosomal RAB-7, identifying a novel function for an ABC transporter. WHT-2 localizes to gut granules where it could play a direct role in controlling Rab localization. Loss of CCZ-1 and GLO-3, which likely function as a guanine nucleotide exchange factor (GEF) for GLO-1, lead to similar disruption of GLO-1 localization. We show that CCZ-1, like GLO-3, is localized to gut granules. WHT-2 does not direct the gut granule association of the GLO-1 GEF and our results point to WHT-2 functioning differently than GLO-3 and CCZ-1 Point mutations in WHT-2 that inhibit its transport activity, but not its subcellular localization, lead to the loss of GLO-1 from gut granules, while other WHT-2 activities are not completely disrupted, suggesting that WHT-2 functions in organelle biogenesis through transport-dependent and transport-independent activities.
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Affiliation(s)
- Laura Voss
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Olivia K Foster
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Logan Harper
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Caitlin Morris
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Sierra Lavoy
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - James N Brandt
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Kimberly Peloza
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Simran Handa
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Amanda Maxfield
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Marie Harp
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Brian King
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | | | - Fiona M Rambo
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Greg J Hermann
- Department of Biology, Lewis & Clark College, Portland, Oregon
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40
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Du J, Ji Y, Qiao L, Liu Y, Lin J. Cellular endo-lysosomal dysfunction in the pathogenesis of non-alcoholic fatty liver disease. Liver Int 2020; 40:271-280. [PMID: 31765080 DOI: 10.1111/liv.14311] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/09/2019] [Accepted: 11/13/2019] [Indexed: 12/13/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD), an increasingly devastating human disorder, is characterized by intrahepatic fat accumulation. Although important progress has been made in understanding NAFLD, the fundamental mechanisms involved in the pathogenesis of NAFLD have not been fully explained. The endo-lysosomal trafficking network is central to lipid metabolism, protein degradation and signal transduction, which are involved in a variety of diseases. In recent years, many genes and pathways in the endo-lysosomal trafficking network and involved in lysosomal biogenesis have been associated with the development and progression of NAFLD. Mutations of these genes and impaired signalling lead to dysfunction in multiple steps of the endo-lysosomal network (endocytic trafficking, membrane fusion and lysosomal degradation), resulting in the accumulation of pathogenic proteins. In this review, we will focus on how alterations in these genes and pathways affect endo-lysosomal trafficking as well as the pathophysiology of NAFLD.
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Affiliation(s)
- Jiang Du
- College of Biomedical Engineering, Xinxiang Medical University, Xinxiang, China.,Stem Cell and Biotherapy Engineering Research Center of Henan, Xinxiang Medical University, Xinxiang, China
| | - Yu Ji
- College of Biomedical Engineering, Xinxiang Medical University, Xinxiang, China
| | - Liang Qiao
- Stem Cell and Biotherapy Engineering Research Center of Henan, Xinxiang Medical University, Xinxiang, China
| | - Yanli Liu
- Stem Cell and Biotherapy Engineering Research Center of Henan, Xinxiang Medical University, Xinxiang, China
| | - Juntang Lin
- Stem Cell and Biotherapy Engineering Research Center of Henan, Xinxiang Medical University, Xinxiang, China
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41
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Gomez RC, Wawro P, Lis P, Alessi DR, Pfeffer SR. Membrane association but not identity is required for LRRK2 activation and phosphorylation of Rab GTPases. J Cell Biol 2019; 218:4157-4170. [PMID: 31624137 PMCID: PMC6891090 DOI: 10.1083/jcb.201902184] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 06/29/2019] [Accepted: 09/06/2019] [Indexed: 01/03/2023] Open
Abstract
Parkinson’s disease–associated LRRK2 kinase is activated on the Golgi by Rab29 but phosphorylates Rab10 there and on other compartments. This study shows that phosphorylation is restricted to membrane surfaces but need not take place on the Golgi. LRRK2 kinase mutations cause familial Parkinson’s disease and increased phosphorylation of a subset of Rab GTPases. Rab29 recruits LRRK2 to the trans-Golgi and activates it there, yet some of LRRK2’s major Rab substrates are not on the Golgi. We sought to characterize the cell biology of LRRK2 activation. Unlike other Rab family members, we show that Rab29 binds nucleotide weakly, is poorly prenylated, and is not bound to GDI in the cytosol; nevertheless, Rab29 only activates LRRK2 when it is membrane bound and GTP bound. Mitochondrially anchored, GTP-bound Rab29 is both a LRRK2 substrate and activator, and it drives accumulation of active LRRK2 and phosphorylated Rab10 on mitochondria. Importantly, mitochondrially anchored LRRK2 is much less capable of phosphorylating plasma membrane–anchored Rab10 than soluble LRRK2. These data support a model in which LRRK2 associates with and dissociates from distinct membrane compartments to phosphorylate Rab substrates; if anchored, LRRK2 can modify misdelivered Rab substrates that then become trapped there because GDI cannot retrieve them.
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Affiliation(s)
- Rachel C Gomez
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA
| | - Paulina Wawro
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA
| | - Pawel Lis
- Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Dario R Alessi
- Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Suzanne R Pfeffer
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA
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42
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Wang G, Hu HB, Chang Y, Huang Y, Song ZQ, Zhou SB, Chen L, Zhang YC, Wu M, Tu HQ, Yuan JF, Wang N, Pan X, Li AL, Zhou T, Zhang XM, He K, Li HY. Rab7 regulates primary cilia disassembly through cilia excision. J Cell Biol 2019; 218:4030-4041. [PMID: 31619485 PMCID: PMC6891077 DOI: 10.1083/jcb.201811136] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 07/07/2019] [Accepted: 09/24/2019] [Indexed: 12/13/2022] Open
Abstract
Wang et al. identify Rab7 as a novel regulator of primary cilia disassembly. Their findings demonstrate that Rab7 localization to primary cilia is required for intraciliary F-actin polymerization, which is indispensable for the regulation of cilia ectocytosis and disassembly. The primary cilium is a sensory organelle that protrudes from the cell surface. Primary cilia undergo dynamic transitions between assembly and disassembly to exert their function in cell signaling. In this study, we identify the small GTPase Rab7 as a novel regulator of cilia disassembly. Depletion of Rab7 potently induced spontaneous ciliogenesis in proliferating cells and promoted cilia elongation during quiescence. Moreover, Rab7 performs an essential role in cilia disassembly; knockdown of Rab7 blocked serum-induced ciliary resorption, and active Rab7 was required for this process. Further, we demonstrate that Rab7 depletion significantly suppresses cilia tip excision, referred to as cilia ectocytosis, which has been identified as required for cilia disassembly. Mechanically, the failure of F-actin polymerization at the site of excision of cilia tips caused suppression of cilia ectocytosis on Rab7 depletion. Overall, our results suggest a novel function for Rab7 in regulating cilia ectocytosis and cilia disassembly via control of intraciliary F-actin polymerization.
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Affiliation(s)
- Guang Wang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China.,Cancer Institute, Institute of Translational Medicine, The Second Military Medical University, Shanghai, China
| | - Huai-Bin Hu
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Yan Chang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China.,Beijing Key Laboratory for Pediatric Diseases of Otolaryngology, Head and Neck Surgery, MOE Key Laboratory of Major Diseases in Children, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Yan Huang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Zeng-Qing Song
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Shi-Bo Zhou
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Liang Chen
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Yu-Cheng Zhang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Min Wu
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Hai-Qing Tu
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Jin-Feng Yuan
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Na Wang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Xin Pan
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Ai-Ling Li
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Tao Zhou
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Xue-Min Zhang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Kun He
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China
| | - Hui-Yan Li
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, China .,Cancer Research Institute of Jilin University, The First Hospital of Jilin University, Changchun, Jilin, China
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43
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Kalde M, Elliott L, Ravikumar R, Rybak K, Altmann M, Klaeger S, Wiese C, Abele M, Al B, Kalbfuß N, Qi X, Steiner A, Meng C, Zheng H, Kuster B, Falter-Braun P, Ludwig C, Moore I, Assaad FF. Interactions between Transport Protein Particle (TRAPP) complexes and Rab GTPases in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:279-297. [PMID: 31264742 DOI: 10.1111/tpj.14442] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/15/2019] [Accepted: 06/11/2019] [Indexed: 05/23/2023]
Abstract
Transport Protein Particle II (TRAPPII) is essential for exocytosis, endocytosis, protein sorting and cytokinesis. In spite of a considerable understanding of its biological role, little information is known about Arabidopsis TRAPPII complex topology and molecular function. In this study, independent proteomic approaches initiated with TRAPP components or Rab-A GTPase variants converge on the TRAPPII complex. We show that the Arabidopsis genome encodes the full complement of 13 TRAPPC subunits, including four previously unidentified components. A dimerization model is proposed to account for binary interactions between TRAPPII subunits. Preferential binding to dominant negative (GDP-bound) versus wild-type or constitutively active (GTP-bound) RAB-A2a variants discriminates between TRAPPII and TRAPPIII subunits and shows that Arabidopsis complexes differ from yeast but resemble metazoan TRAPP complexes. Analyzes of Rab-A mutant variants in trappii backgrounds provide genetic evidence that TRAPPII functions upstream of RAB-A2a, allowing us to propose that TRAPPII is likely to behave as a guanine nucleotide exchange factor (GEF) for the RAB-A2a GTPase. GEFs catalyze exchange of GDP for GTP; the GTP-bound, activated, Rab then recruits a diverse local network of Rab effectors to specify membrane identity in subsequent vesicle fusion events. Understanding GEF-Rab interactions will be crucial to unravel the co-ordination of plant membrane traffic.
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Affiliation(s)
- Monika Kalde
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - Liam Elliott
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - Raksha Ravikumar
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Katarzyna Rybak
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Melina Altmann
- Institute of Network Biology (INET), Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Neuherberg, 85764, Germany
| | - Susan Klaeger
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, 85354, Germany
| | - Christian Wiese
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Miriam Abele
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Benjamin Al
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Nils Kalbfuß
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Xingyun Qi
- Department of Biology, McGill University, Montreal, H3B 1A1, Canada
| | - Alexander Steiner
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Chen Meng
- BayBioMS, Bavarian Center for Biomolecular Mass Spectrometry, Technische Universität München, Freising, 85354, Germany
| | - Huanquan Zheng
- Department of Biology, McGill University, Montreal, H3B 1A1, Canada
| | - Bernhard Kuster
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, 85354, Germany
| | - Pascal Falter-Braun
- Institute of Network Biology (INET), Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Neuherberg, 85764, Germany
- Faculty of Biology, Microbe-Host-Interactions, Ludwig-Maximilians-Universität (LMU) München, Planegg-Martinsried, 82152, Germany
| | - Christina Ludwig
- BayBioMS, Bavarian Center for Biomolecular Mass Spectrometry, Technische Universität München, Freising, 85354, Germany
| | - Ian Moore
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - Farhah F Assaad
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
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Haredi Abdelmonsef A. Computer-aided identification of lung cancer inhibitors through homology modeling and virtual screening. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2019. [DOI: 10.1186/s43042-019-0008-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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45
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Ehrmann A, Nguyen B, Seifert U. Interlinked GTPase cascades provide a motif for both robust switches and oscillators. J R Soc Interface 2019; 16:20190198. [PMID: 31387482 DOI: 10.1098/rsif.2019.0198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
GTPases regulate a wide range of cellular processes, such as intracellular vesicular transport, signal transduction and protein translation. These hydrolase enzymes operate as biochemical switches by toggling between an active guanosine triphosphate (GTP)-bound state and an inactive guanosine diphosphate (GDP)-bound state. We compare two network motifs, a single-species switch and an interlinked cascade that consists of two species coupled through positive and negative feedback loops. We find that interlinked cascades are closer to the ideal all-or-none switch and are more robust against fluctuating signals. While the single-species switch can only achieve bistability, interlinked cascades can be converted into oscillators by tuning the cofactor concentrations, which catalyse the activity of the cascade. These regimes can only be achieved with sufficient chemical driving provided by GTP hydrolysis. In this study, we present a thermodynamically consistent model that can achieve bistability and oscillations with the same feedback motif.
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Affiliation(s)
- Andreas Ehrmann
- II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany
| | - Basile Nguyen
- II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany
| | - Udo Seifert
- II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany
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Rosquete MR, Worden N, Ren G, Sinclair RM, Pfleger S, Salemi M, Phinney BS, Domozych D, Wilkop T, Drakakaki G. AtTRAPPC11/ROG2: A Role for TRAPPs in Maintenance of the Plant Trans-Golgi Network/Early Endosome Organization and Function. THE PLANT CELL 2019; 31:1879-1898. [PMID: 31175171 PMCID: PMC6713296 DOI: 10.1105/tpc.19.00110] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/06/2019] [Accepted: 06/02/2019] [Indexed: 05/14/2023]
Abstract
The dynamic trans-Golgi network/early endosome (TGN/EE) facilitates cargo sorting and trafficking and plays a vital role in plant development and environmental response. Transport protein particles (TRAPPs) are multi-protein complexes acting as guanine nucleotide exchange factors and possibly as tethers, regulating intracellular trafficking. TRAPPs are essential in all eukaryotic cells and are implicated in a number of human diseases. It has been proposed that they also play crucial roles in plants; however, our current knowledge about the structure and function of plant TRAPPs is very limited. Here, we identified and characterized AtTRAPPC11/RESPONSE TO OLIGOGALACTURONIDE2 (AtTRAPPC11/ROG2), a TGN/EE-associated, evolutionarily conserved TRAPP protein in Arabidopsis (Arabidopsis thaliana). AtTRAPPC11/ROG2 regulates TGN integrity, as evidenced by altered TGN/EE association of several residents, including SYNTAXIN OF PLANTS61, and altered vesicle morphology in attrappc11/rog2 mutants. Furthermore, endocytic traffic and brefeldin A body formation are perturbed in attrappc11/rog2, suggesting a role for AtTRAPPC11/ROG2 in regulation of endosomal function. Proteomic analysis showed that AtTRAPPC11/ROG2 defines a hitherto uncharacterized TRAPPIII complex in plants. In addition, attrappc11/rog2 mutants are hypersensitive to salinity, indicating an undescribed role of TRAPPs in stress responses. Overall, our study illustrates the plasticity of the endomembrane system through TRAPP protein functions and opens new avenues to explore this dynamic network.
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Affiliation(s)
| | - Natasha Worden
- Department of Plant Sciences University of California, Davis, California 95616
| | - Guangxi Ren
- Department of Plant Sciences University of California, Davis, California 95616
| | - Rosalie M Sinclair
- Department of Plant Sciences University of California, Davis, California 95616
| | - Sina Pfleger
- Department of Plant Sciences University of California, Davis, California 95616
| | - Michelle Salemi
- Genome Center, University of California, Davis, California 95616
| | - Brett S Phinney
- Genome Center, University of California, Davis, California 95616
| | - David Domozych
- Department of Biology and Skidmore Microscopy Imaging Center, Skidmore College, Saratoga Springs, New York 12866
| | - Thomas Wilkop
- Department of Plant Sciences University of California, Davis, California 95616
- Light Microscopy Core, University of Kentucky, Lexington, Kentucky 40536
| | - Georgia Drakakaki
- Department of Plant Sciences University of California, Davis, California 95616
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De Vries L, Finana F, Cathala C, Ronsin B, Cussac D. Innovative Bioluminescence Resonance Energy Transfer Assay Reveals Differential Agonist-Induced D2 Receptor Intracellular Trafficking and Arrestin-3 Recruitment. Mol Pharmacol 2019; 96:308-319. [PMID: 31266815 DOI: 10.1124/mol.119.115998] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/19/2019] [Indexed: 01/14/2023] Open
Abstract
The dopamine D2 receptor (D2R) mediates ligand-biased signaling with potential therapeutic implications. However, internalization, choice of endocytic routes, and degradation of the D2R in lysosomes may also participate in agonist-directed trafficking. We developed bioluminescence resonance energy transfer (BRET) assays that measure relative distances between Renilla luciferase8-tagged D2R and green fluorescent protein 2 (GFP2)-tagged K-Ras (plasma membrane marker), and between luciferase8-tagged D2R and GFP2-Rab5 (early), GFP2-Rab4 (recycling), or GFP2-Rab7 (late) endosomal markers. The BRET signal between D2R-Luc and GFP2-K-Ras was robustly diminished after receptor internalization induced by dopamine, with subsequent BRET signals increasing when luciferase8-tagged D2R approached GFP2-Rab proteins in endosomal compartments. All BRET signals were blocked by the selective D2R antagonist haloperidol and were decreased by low temperature and high sucrose blocks, two parameters interfering with internalization. Some antipsychotic drugs, such as aripiprazole, are less efficacious in internalizing D2R than most of the antiparkinsonian agents. However, antipsychotics were nearly as efficacious as antiparkinsonians in directing the D2R toward early and recycling endosomes. The Rab7 marker for the late endosome/lysosome route was also capable of discriminating between D2R compounds. We could show that some drugs engaged the D2R either to interact preferentially with arrestin-3 or to internalize. Our study revealed that D2R trafficking in cells was differentially regulated by antipsychotic and antiparkinsonian drugs. Taken together, the BRET assays reported here could further help decipher D2R ligand-induced arrestin-3 recruitment and trafficking, with potentially more selective therapeutic profiles and fewer undesired side effects.
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Affiliation(s)
- Luc De Vries
- Central Nervous System Innovation Unit, CEPC Campans - Belair de Campans, Castres, France (L.D.V., F.F., C.C., D.C.) and CNRS, UMR5547, Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Toulouse, France (B.R.)
| | - Frédéric Finana
- Central Nervous System Innovation Unit, CEPC Campans - Belair de Campans, Castres, France (L.D.V., F.F., C.C., D.C.) and CNRS, UMR5547, Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Toulouse, France (B.R.)
| | - Claudie Cathala
- Central Nervous System Innovation Unit, CEPC Campans - Belair de Campans, Castres, France (L.D.V., F.F., C.C., D.C.) and CNRS, UMR5547, Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Toulouse, France (B.R.)
| | - Brice Ronsin
- Central Nervous System Innovation Unit, CEPC Campans - Belair de Campans, Castres, France (L.D.V., F.F., C.C., D.C.) and CNRS, UMR5547, Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Toulouse, France (B.R.)
| | - Didier Cussac
- Central Nervous System Innovation Unit, CEPC Campans - Belair de Campans, Castres, France (L.D.V., F.F., C.C., D.C.) and CNRS, UMR5547, Centre de Biologie du Développement, Université de Toulouse III-Paul Sabatier, Toulouse, France (B.R.)
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48
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Shigella promotes major alteration of gut epithelial physiology and tissue invasion by shutting off host intracellular transport. Proc Natl Acad Sci U S A 2019; 116:13582-13591. [PMID: 31209035 DOI: 10.1073/pnas.1902922116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Intracellular trafficking pathways in eukaryotic cells are essential to maintain organelle identity and structure, and to regulate cell communication with its environment. Shigella flexneri invades and subverts the human colonic epithelium by the injection of virulence factors through a type 3 secretion system (T3SS). In this work, we report the multiple effects of two S. flexneri effectors, IpaJ and VirA, which target small GTPases of the Arf and Rab families, consequently inhibiting several intracellular trafficking pathways. IpaJ and VirA induce large-scale impairment of host protein secretion and block the recycling of surface receptors. Moreover, these two effectors decrease clathrin-dependent and -independent endocytosis. Therefore, S. flexneri infection induces a global blockage of host cell intracellular transport, affecting the exchange between cells and their external environment. The combined action of these effectors disorganizes the epithelial cell polarity, disturbs epithelial barrier integrity, promotes multiple invasion events, and enhances the pathogen capacity to penetrate into the colonic tissue in vivo.
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Zhang Y, Wan X, Wang HH, Pan MH, Pan ZN, Sun SC. RAB35 depletion affects spindle formation and actin-based spindle migration in mouse oocyte meiosis. ACTA ACUST UNITED AC 2019; 25:359-372. [DOI: 10.1093/molehr/gaz027] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/28/2019] [Accepted: 05/17/2019] [Indexed: 12/16/2022]
Abstract
Abstract
Mammalian oocyte maturation involves a unique asymmetric cell division, in which meiotic spindle formation and actin filament-mediated spindle migration to the oocyte cortex are key processes. Here, we report that the vesicle trafficking regulator, RAB35 GTPase, is involved in regulating cytoskeleton dynamics in mouse oocytes. RAB35 GTPase mainly accumulated at the meiotic spindle periphery and cortex during oocyte meiosis. Depletion of RAB35 by morpholino microinjection led to aberrant polar body extrusion and asymmetric division defects in almost half the treated oocytes. We also found that RAB35 affected SIRT2 and αTAT for tubulin acetylation, which further modulated microtubule stability and meiotic spindle formation. Additionally, we found that RAB35 associated with RHOA in oocytes and modulated the ROCK–cofilin pathway for actin assembly, which further facilitated spindle migration for oocyte asymmetric division. Importantly, microinjection of Myc-Rab35 cRNA into RAB35-depleted oocytes could significantly rescue these defects. In summary, our results suggest that RAB35 GTPase has multiple roles in spindle stability and actin-mediated spindle migration in mouse oocyte meiosis.
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Affiliation(s)
- Yu Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Xiang Wan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Hong-Hui Wang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Meng-Hao Pan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Zhen-Nan Pan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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50
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Locke MN, Thorner J. Regulation of TORC2 function and localization by Rab5 GTPases in Saccharomyces cerevisiae. Cell Cycle 2019; 18:1084-1094. [PMID: 31068077 DOI: 10.1080/15384101.2019.1616999] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The evolutionarily conserved Target of Rapamycin (TOR) complex-2 (TORC2) is an essential regulator of plasma membrane homeostasis in budding yeast (Saccharomyces cerevisiae). In this yeast, TORC2 phosphorylates and activates the effector protein kinase Ypk1 and its paralog Ypk2. These protein kinases, in turn, carry out all the crucial functions of TORC2 by phosphorylating and thereby controlling the activity of at least a dozen downstream substrates. A previously uncharacterized interplay between the Rab5 GTPases and TORC2 signaling was uncovered through analysis of a newly suspected Ypk1 target. Muk1, one of two guanine nucleotide exchange factors for the Rab5 GTPases, was found to be a physiologically relevant Ypk1 substrate; and, genetic analysis indicates that Ypk1-mediated phosphorylation activates the guanine nucleotide exchange activity of Muk1. Second, it was demonstrated both in vivo and in vitro that the GTP-bound state of the Rab5 GTPase Vps21/Ypt51 physically associates with TORC2 and acts as a direct positive effector required for full TORC2 activity. These interrelationships provide a self-reinforcing control circuit for sustained up-regulation of TORC2-Ypk1 signaling. In this overview, we summarize the experimental basis of these findings, their implications, and speculate as to the molecular basis for Rab5-mediated TORC2 activation.
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Affiliation(s)
- Melissa N Locke
- a Division of Biochemistry, Biophysics & Structural Biology, and Division of Cell & Developmental Biology, Department of Molecular and Cell Biology , University of California at Berkeley , Berkeley , CA , USA
| | - Jeremy Thorner
- a Division of Biochemistry, Biophysics & Structural Biology, and Division of Cell & Developmental Biology, Department of Molecular and Cell Biology , University of California at Berkeley , Berkeley , CA , USA
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