1
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de Leeuw SM, Nuriel T. Intracellular cholesterol visualization in brain tissue using D4H ∗. STAR Protoc 2024; 5:102779. [PMID: 38100357 PMCID: PMC10762518 DOI: 10.1016/j.xpro.2023.102779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 10/31/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Studying cholesterol biology in the brain has been greatly hindered by the lack of adequate cholesterol visualization techniques. Here, we present a protocol for using a high-affinity cholesterol probe D4H∗-mCherry as a histology reagent in mouse or human brain tissue. We describe steps for D4H∗ tissue treatment and crosslinking leading to stable labeling of intracellular membrane cholesterol. Furthermore, co-labeling with Rab5 endosomal marker and optimized buffers to reduce background enable punctate cholesterol visualization within the organelle membranes.
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Affiliation(s)
- Sherida M de Leeuw
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, 630 West 168th Street, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
| | - Tal Nuriel
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, 630 West 168th Street, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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2
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Baker MJ, Blau KU, Anderson AJ, Palmer CS, Fielden LF, Crameri JJ, Milenkovic D, Thorburn DR, Frazier AE, Langer T, Stojanovski D. CLPB disaggregase dysfunction impacts the functional integrity of the proteolytic SPY complex. J Cell Biol 2024; 223:e202305087. [PMID: 38270563 PMCID: PMC10818064 DOI: 10.1083/jcb.202305087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/07/2023] [Accepted: 12/21/2023] [Indexed: 01/26/2024] Open
Abstract
CLPB is a mitochondrial intermembrane space AAA+ domain-containing disaggregase. CLPB mutations are associated with 3-methylglutaconic aciduria and neutropenia; however, the molecular mechanism underscoring disease and the contribution of CLPB substrates to disease pathology remains unknown. Interactions between CLPB and mitochondrial quality control (QC) factors, including PARL and OPA1, have been reported, hinting at dysregulation of organelle QC in disease. Utilizing proteomic and biochemical approaches, we show a stress-specific aggregation phenotype in a CLPB-null environment and define the CLPB substrate profile. We illustrate an interplay between intermembrane space proteins including CLPB, HAX1, HTRA2, and the inner membrane quality control proteins (STOML2, PARL, YME1L1; SPY complex), with CLPB deficiency impeding SPY complex function by virtue of protein aggregation in the intermembrane space. We conclude that there is an interdependency of mitochondrial QC components at the intermembrane space/inner membrane interface, and perturbations to this network may underscore CLPB disease pathology.
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Affiliation(s)
- Megan J. Baker
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Kai Uwe Blau
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Alexander J. Anderson
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Catherine S. Palmer
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Laura F. Fielden
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Jordan J. Crameri
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Dusanka Milenkovic
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - David R. Thorburn
- Royal Children’s Hospital and Department of Paediatrics, Murdoch Children’s Research Institute, The University of Melbourne, Parkville, Australia
- Victorian Clinical Genetics Services, Royal Children’s Hospital, Parkville, Australia
| | - Ann E. Frazier
- Royal Children’s Hospital and Department of Paediatrics, Murdoch Children’s Research Institute, The University of Melbourne, Parkville, Australia
| | - Thomas Langer
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Diana Stojanovski
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
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3
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Hu Y, Jiang L, Wang G, Song Y, Shan Z, Wang X, Deng G, Shi J, Tian G, Zeng X, Liu L, Chen H, Li C. M6PR interacts with the HA2 subunit of influenza A virus to facilitate the fusion of viral and endosomal membranes. Sci China Life Sci 2024; 67:579-595. [PMID: 38038885 DOI: 10.1007/s11427-023-2471-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 10/18/2023] [Indexed: 12/02/2023]
Abstract
Influenza A virus (IAV) commandeers numerous host cellular factors for successful replication. However, very few host factors have been revealed to be involved in the fusion of viral envelope and late endosomal membranes. In this study, we identified cation-dependent mannose-6-phosphate receptor (M6PR) as a crucial host factor for the replication of IAV. We found that siRNA knockdown of M6PR expression significantly reduced the growth titers of different subtypes of IAV, and that the inhibitory effect of M6PR siRNA treatment on IAV growth was overcome by the complement of exogenously expressed M6PR. When A549 cells were treated with siRNA targeting M6PR, the nuclear accumulation of viral nucleoprotein (NP) was dramatically inhibited at early timepoints post-infection, indicating that M6PR engages in the early stage of the IAV replication cycle. By investigating the role of M6PR in the individual entry and post-entry steps of IAV replication, we found that the downregulation of M6PR expression had no effect on attachment, internalization, early endosome trafficking, or late endosome acidification. However, we found that M6PR expression was critical for the fusion of viral envelope and late endosomal membranes. Of note, M6PR interacted with the hemagglutinin (HA) protein of IAV, and further studies showed that the lumenal domain of M6PR and the ectodomain of HA2 mediated the interaction and directly promoted the fusion of the viral and late endosomal membranes, thereby facilitating IAV replication. Together, our findings highlight the importance of the M6PR-HA interaction in the fusion of viral and late endosomal membranes during IAV replication.
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Affiliation(s)
- Yuzhen Hu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Li Jiang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Guangwen Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Yangming Song
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Zhibo Shan
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Xuyuan Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Guohua Deng
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Jianzhong Shi
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Guobin Tian
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Xianying Zeng
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Liling Liu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China
| | - Hualan Chen
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China.
| | - Chengjun Li
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150069, China.
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van der Beek J, de Heus C, Sanza P, Liv N, Klumperman J. Loss of the HOPS complex disrupts early-to-late endosome transition, impairs endosomal recycling and induces accumulation of amphisomes. Mol Biol Cell 2024; 35:ar40. [PMID: 38198575 PMCID: PMC10916860 DOI: 10.1091/mbc.e23-08-0328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/22/2023] [Accepted: 01/05/2024] [Indexed: 01/12/2024] Open
Abstract
The multisubunit HOPS tethering complex is a well-established regulator of lysosome fusion with late endosomes and autophagosomes. However, the role of the HOPS complex in other stages of endo-lysosomal trafficking is not well understood. To address this, we made HeLa cells knocked out for the HOPS-specific subunits Vps39 or Vps41, or the HOPS-CORVET-core subunits Vps18 or Vps11. In all four knockout cells, we found that endocytosed cargos were trapped in enlarged endosomes that clustered in the perinuclear area. By correlative light-electron microscopy, these endosomes showed a complex ultrastructure and hybrid molecular composition, displaying markers for early (Rab5, PtdIns3P, EEA1) as well as late (Rab7, CD63, LAMP1) endosomes. These "HOPS bodies" were not acidified, contained enzymatically inactive cathepsins and accumulated endocytosed cargo and cation-independent mannose-6-phosphate receptor (CI-MPR). Consequently, CI-MPR was depleted from the TGN, and secretion of lysosomal enzymes to the extracellular space was enhanced. Strikingly, HOPS bodies also contained the autophagy proteins p62 and LC3, defining them as amphisomes. Together, these findings show that depletion of the lysosomal HOPS complex has a profound impact on the functional organization of the entire endosomal system and suggest the existence of a HOPS-independent mechanism for amphisome formation.
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Affiliation(s)
- Jan van der Beek
- Center for Molecular Medicine, University Medical Center Utrecht, Institute of Biomembranes, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Cecilia de Heus
- Center for Molecular Medicine, University Medical Center Utrecht, Institute of Biomembranes, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Paolo Sanza
- Center for Molecular Medicine, University Medical Center Utrecht, Institute of Biomembranes, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Nalan Liv
- Center for Molecular Medicine, University Medical Center Utrecht, Institute of Biomembranes, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Judith Klumperman
- Center for Molecular Medicine, University Medical Center Utrecht, Institute of Biomembranes, Utrecht University, 3584 CX Utrecht, The Netherlands
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5
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Narum S, Deal B, Ogasawara H, Mancuso JN, Zhang J, Salaita K. An Endosomal Escape Trojan Horse Platform to Improve Cytosolic Delivery of Nucleic Acids. ACS Nano 2024; 18:6186-6201. [PMID: 38346399 PMCID: PMC10906071 DOI: 10.1021/acsnano.3c09027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/11/2023] [Accepted: 12/26/2023] [Indexed: 02/17/2024]
Abstract
Endocytosis is a major bottleneck toward cytosolic delivery of nucleic acids, as the vast majority of nucleic acid drugs remain trapped within endosomes. Current trends to overcome endosomal entrapment and subsequent degradation provide varied success; however, active delivery agents such as cell-penetrating peptides have emerged as a prominent strategy to improve cytosolic delivery. Yet, these membrane-active agents have poor selectivity for endosomal membranes, leading to toxicity. A hallmark of endosomes is their acidic environment, which aids in degradation of foreign materials. Here, we develop a pH-triggered spherical nucleic acid that provides smart antisense oligonucleotide (ASO) release upon endosomal acidification and selective membrane disruption, termed DNA EndosomaL Escape Vehicle Response (DELVR). We anchor i-Motif DNA to a nanoparticle (AuNP), where the complement strand contains both an ASO sequence and a functionalized endosomal escape peptide (EEP). By orienting the EEP toward the AuNP core, the EEP is inactive until it is released through acidification-induced i-Motif folding. In this study, we characterize a small library of i-Motif duplexes to develop a structure-switching nucleic acid sequence triggered by endosomal acidification. We evaluate antisense efficacy using HIF1a, a hypoxic indicator upregulated in many cancers, and demonstrate dose-dependent activity through RT-qPCR. We show that DELVR significantly improves ASO efficacy in vitro. Finally, we use fluorescence lifetime imaging and activity measurement to show that DELVR benefits synergistically from nuclease- and pH-driven release strategies with increased ASO endosomal escape efficiency. Overall, this study develops a modular platform that improves the cytosolic delivery of nucleic acid therapeutics and offers key insights for overcoming intracellular barriers.
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Affiliation(s)
- Steven Narum
- Department
of Biomedical Engineering, Georgia Institute
of Technology and Emory University, Atlanta, Georgia 30322, United States
| | - Brendan Deal
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Hiroaki Ogasawara
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | | | - Jiahui Zhang
- Department
of Biomedical Engineering, Georgia Institute
of Technology and Emory University, Atlanta, Georgia 30322, United States
| | - Khalid Salaita
- Department
of Biomedical Engineering, Georgia Institute
of Technology and Emory University, Atlanta, Georgia 30322, United States
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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6
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Shukla S, Chen W, Rao S, Yang S, Ou C, Larsen KP, Hummer G, Hanson PI, Hurley JH. Mechanism and cellular function of direct membrane binding by the ESCRT and ERES-associated Ca 2+-sensor ALG-2. Proc Natl Acad Sci U S A 2024; 121:e2318046121. [PMID: 38386713 PMCID: PMC10907313 DOI: 10.1073/pnas.2318046121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/17/2024] [Indexed: 02/24/2024] Open
Abstract
Apoptosis linked Gene-2 (ALG-2) is a multifunctional intracellular Ca2+ sensor and the archetypal member of the penta-EF hand protein family. ALG-2 functions in the repair of damage to both the plasma and lysosome membranes and in COPII-dependent budding at endoplasmic reticulum exit sites (ERES). In the presence of Ca2+, ALG-2 binds to ESCRT-I and ALIX in membrane repair and to SEC31A at ERES. ALG-2 also binds directly to acidic membranes in the presence of Ca2+ by a combination of electrostatic and hydrophobic interactions. By combining giant unilamellar vesicle-based experiments and molecular dynamics simulations, we show that charge-reversed mutants of ALG-2 at these locations disrupt membrane recruitment. ALG-2 membrane binding mutants have reduced or abrogated ERES localization in response to Thapsigargin-induced Ca2+ release but still localize to lysosomes following lysosomal Ca2+ release. In vitro reconstitution shows that the ALG-2 membrane-binding defect can be rescued by binding to ESCRT-I. These data thus reveal the nature of direct Ca2+-dependent membrane binding and its interplay with Ca2+-dependent protein binding in the cellular functions of ALG-2.
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Affiliation(s)
- Sankalp Shukla
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA94720
| | - Wei Chen
- Department of Biological Chemistry, University of Michigan School of Medicine, Ann Arbor, MI48109
| | - Shanlin Rao
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main60438, Germany
| | - Serim Yang
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Chenxi Ou
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA94720
| | - Kevin P. Larsen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA94720
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main60438, Germany
- Institute of Biophysics, Goethe UniversityFrankfurt, Frankfurt am Main60438, Germany
| | - Phyllis I. Hanson
- Department of Biological Chemistry, University of Michigan School of Medicine, Ann Arbor, MI48109
| | - James H. Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA94720
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA94720
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7
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Muzzioli R, Gallo A. The Interaction and Effect of a Small MitoBlock Library as Inhibitor of ALR Protein-Protein Interaction Pathway. Int J Mol Sci 2024; 25:1174. [PMID: 38256258 PMCID: PMC10816046 DOI: 10.3390/ijms25021174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
MIA40 and ALR of the MIA pathway mediate the import of protein precursors that form disulfides into the mitochondrial intermembrane space. This import pathway is suggested to be a linear pathway in which MIA40 first binds to the precursor via a disulfide linkage and oxidizes it. Subsequently, ALR re-oxidizes MIA40 and then ALR transfers electrons to terminal electron acceptors. However, the precise mechanism by which ALR and MIA40 coordinate translocation is unknown. With a collection of small molecule modulators (MB-5 to MB-9 and MB-13) that inhibit ALR activity, we characterized the import mechanism in mitochondria. NMR studies show that most of the compounds bind to a similar region in ALR. Mechanistic studies with small molecules demonstrate that treatment with compound MB-6 locks the precursor in a state bound to MIA40, blocking re-oxidation of MIA40 by ALR. Thus, small molecules that target a similar region in ALR alter the dynamics of the MIA import pathway differently, resulting in a set of probes that are useful for studying the catalysis of the redox-regulated import pathway in model systems.
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8
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Liu S, Liu X, Xian J, Feng Z, Tian Y, Wang W, Tian X. Visualizing intracellular membrane interactions and cell type-specific differentiation in ferroptosis and apoptosis with Boranil-Carbazole derivative. Bioorg Chem 2024; 142:106949. [PMID: 37918149 DOI: 10.1016/j.bioorg.2023.106949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 10/17/2023] [Accepted: 10/26/2023] [Indexed: 11/04/2023]
Abstract
Intracellular lipid systems play essential roles in various physiological functions and cell growth processes. However, our understanding of the intricate interactions within this system, especially between mitochondria and lipid droplets, is limited, particularly in the context of cancer cells' altered lipid metabolism. To address this, our study introduces an N-B-O BODIPY-hexylcarbazole derivative, named Cz-Boranil, that sets a new benchmark in visualizing these critical interactions. Cz-Boranil's unique capability lies in its ability to display distinct intracellular distribution patterns in both normal and cancer cells, offering nuanced cell type-specific differentiation. More impressively, this probe tracks the coordinated interactions of lipid droplets and mitochondria during the critical processes of ferroptosis and apoptosis. We believe that the innovative capabilities of Cz-Boranil will revolutionize our understanding of intracellular lipid interactions and prove pivotal in identifying and studying cancerous cells.
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Affiliation(s)
- Shangke Liu
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, Department of Radiology and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu 610000, Sichuan Province, China
| | - Xiaolu Liu
- School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Jinghong Xian
- Department of Pathology, West China Hospital, Sichuan University, Chengdu, China
| | - Zhihui Feng
- College of Chemistry and Chemical Engineering, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230601, China
| | - Yupeng Tian
- College of Chemistry and Chemical Engineering, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230601, China
| | - Weiya Wang
- Department of Pathology, West China Hospital, Sichuan University, Chengdu, China.
| | - Xiaohe Tian
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, Department of Radiology and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu 610000, Sichuan Province, China
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9
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Maruyama T, Noda NN. Protocol for real-time imaging of membrane fission by mitofissin. STAR Protoc 2023; 4:102590. [PMID: 37738122 PMCID: PMC10520655 DOI: 10.1016/j.xpro.2023.102590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 08/04/2023] [Accepted: 09/01/2023] [Indexed: 09/24/2023] Open
Abstract
Yeast mitofissin Atg44 is a mitochondrial intermembrane space protein that causes membrane fission required for mitophagy. Here, we present a protocol for observing Atg44-mediated membrane fission. We describe steps for recombinant Atg44 purification, lipid nanotube preparation as model membranes, and Atg44-mediated membrane fission real-time observation. We then detail procedures for tube radius estimation using confocal microscopy. This protocol can also be adapted to the study of membrane fission by other proteins. For complete details on the use and execution of this protocol, please refer to Fukuda et al. (2023).1.
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Affiliation(s)
- Tatsuro Maruyama
- Institute of Microbial Chemistry (BIKAKEN), Shinagawa-ku, Tokyo 141-0021, Japan
| | - Nobuo N Noda
- Institute of Microbial Chemistry (BIKAKEN), Shinagawa-ku, Tokyo 141-0021, Japan; Institute for Genetic Medicine, Hokkaido University, Sapporo, Hokkaido 060-0815, Japan.
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10
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Kim Y, Mavodza G, Senkal CE, Burd CG. Cholesterol-dependent homeostatic regulation of very long chain sphingolipid synthesis. J Cell Biol 2023; 222:e202308055. [PMID: 37787764 PMCID: PMC10547602 DOI: 10.1083/jcb.202308055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/08/2023] [Accepted: 09/18/2023] [Indexed: 10/04/2023] Open
Abstract
Sphingomyelin plays a key role in cellular cholesterol homeostasis by binding to and sequestering cholesterol in the plasma membrane. We discovered that synthesis of very long chain (VLC) sphingomyelins is inversely regulated by cellular cholesterol levels; acute cholesterol depletion elicited a rapid induction of VLC-sphingolipid synthesis, increased trafficking to the Golgi apparatus and plasma membrane, while cholesterol loading reduced VLC-sphingolipid synthesis. This sphingolipid-cholesterol metabolic axis is distinct from the sterol responsive element binding protein pathway as it requires ceramide synthase 2 (CerS2) activity, epidermal growth factor receptor signaling, and was unaffected by inhibition of protein translation. Depletion of VLC-ceramides reduced plasma membrane cholesterol content, reduced plasma membrane lipid packing, and unexpectedly resulted in the accumulation of cholesterol in the cytoplasmic leaflet of the lysosome membrane. This study establishes the existence of a cholesterol-sphingolipid regulatory axis that maintains plasma membrane lipid homeostasis via regulation of sphingomyelin synthesis and trafficking.
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Affiliation(s)
- Yeongho Kim
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Grace Mavodza
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Can E. Senkal
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
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11
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LaLone V, Smith D, Diaz-Espinosa J, Rosania GR. Quantitative Raman chemical imaging of intracellular drug-membrane aggregates and small molecule drug precipitates in cytoplasmic organelles. Adv Drug Deliv Rev 2023; 202:115107. [PMID: 37769851 PMCID: PMC10841539 DOI: 10.1016/j.addr.2023.115107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 10/02/2023]
Abstract
Raman confocal microscopes have been used to visualize the distribution of small molecule drugs within different subcellular compartments. This visualization allows the discovery, characterization, and detailed analysis of the molecular transport phenomena underpinning the Volume of Distribution - a key parameter governing the systemic pharmacokinetics of small molecule drugs. In the specific case of lipophilic small molecules with large Volumes of Distribution, chemical imaging studies using Raman confocal microscopes have revealed how weakly basic, poorly soluble drug molecules can accumulate inside cells by forming stable, supramolecular complexes in association with cytoplasmic membranes or by precipitating out within organelles. To study the self-assembly and function of the resulting intracellular drug inclusions, Raman chemical imaging methods have been developed to measure and map the mass, concentration, and ionization state of drug molecules at a microscopic, subcellular level. Beyond the field of drug delivery, Raman chemical imaging techniques relevant to the study of microscopic drug precipitates and drug-lipid complexes which form inside cells are also being developed by researchers with seemingly unrelated scientific interests. Highlighting advances in data acquisition, calibration methods, and computational data management and analysis tools, this review will cover a decade of technological developments that enable the conversion of spectral signals obtained from Raman confocal microscopes into new discoveries and information about previously unknown, concentrative drug transport pathways driven by soluble-to-insoluble phase transitions occurring within the cytoplasmic organelles of eukaryotic cells.
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Affiliation(s)
- Vernon LaLone
- Cambium Analytica Research Laboratories, Traverse City, MI, United States
| | - Doug Smith
- Cambium Analytica Research Laboratories, Traverse City, MI, United States
| | - Jennifer Diaz-Espinosa
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States
| | - Gus R Rosania
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States.
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12
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Hu LL, Chen S, Shen MY, Huang QY, Li HG, Sun SC, Wang JL, Luo XQ. Aflatoxin B1 impairs porcine oocyte quality via disturbing intracellular membrane system and ATP production. Ecotoxicol Environ Saf 2023; 263:115213. [PMID: 37421895 DOI: 10.1016/j.ecoenv.2023.115213] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/10/2023]
Abstract
Aflatoxin is the most common type of mycotoxins in contaminated corn, peanuts and rice, which affects the livestock and ultimately endangers human health. Aflatoxin is reported to have carcinogenicity, mutation, growth retardation, immunosuppression and reproductive toxicity. In present study we reported the causes for the declined porcine oocyte quality under aflatoxin exposure. We set up an in vitro exposure model and showed that aflatoxin B1 disturbed cumulus cell expansion and oocyte polar body extrusion. We found that aflatoxin B1 exposure disrupted ER distribution and elevated the expression of GRP78, indicating the occurrence of ER stress, and the increased calcium storage also confirmed this. Besides, the structure of cis-Golgi apparatus, another intracellular membrane system was also affected, showing with decreased GM130 expression. The oocytes under aflatoxin B1 exposure showed aberrant lysosome accumulation and higher LAMP2 expression, a marker for lysosome membrane protection, and this might be due to the aberrant mitochondria function with low ATP production and the increase of apoptosis, since we found that BAX expression increased, and ribosomal protein which is also an apoptosis-related factor RPS3 decreased. Taken together, our study revealed that aflatoxin B1 impairs intracellular membrane system ER, Golgi apparatus, lysosome and mitochondria function to affect porcine oocyte maturation quality.
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Affiliation(s)
- Lin-Lin Hu
- Reproductive Medicine, Guangxi Medical and Health Key Discipline Construction Project, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, China
| | - Shun Chen
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Meng-Ying Shen
- Reproductive Medicine, Guangxi Medical and Health Key Discipline Construction Project, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, China
| | - Qiu-Yan Huang
- Reproductive Medicine, Guangxi Medical and Health Key Discipline Construction Project, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, China
| | - Hong-Ge Li
- Reproductive Medicine, Guangxi Medical and Health Key Discipline Construction Project, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, China; College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
| | - Jun-Li Wang
- Reproductive Medicine, Guangxi Medical and Health Key Discipline Construction Project, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, China; Industrial College of Biomedicine and Health Industry, Youjiang Medical University for Nationalities, Baise, Guangxi 533000, China.
| | - Xiao-Qiong Luo
- Reproductive Medicine, Guangxi Medical and Health Key Discipline Construction Project, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, China.
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13
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Chang CY, Chen LJ, Li HM. Chloroplast import motor subunits FtsHi1 and FtsHi2 are located on opposite sides of the inner envelope membrane. Proc Natl Acad Sci U S A 2023; 120:e2307747120. [PMID: 37669373 PMCID: PMC10500165 DOI: 10.1073/pnas.2307747120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/07/2023] [Indexed: 09/07/2023] Open
Abstract
Protein import into chloroplasts is powered by ATP hydrolysis in the stroma. Establishing the identity and functional mechanism of the stromal ATPase motor that drives import is critical for understanding chloroplast biogenesis. Recently, a complex consisting of Ycf2, FtsHi1, FtsHi2, FtsHi4, FtsHi5, FtsH12, and malate dehydrogenase was shown to be important for chloroplast protein import, and it has been proposed to act as the motor driving protein translocation across the chloroplast envelope into the stroma. To gain further mechanistic understanding of how the motor functions, we performed membrane association and topology analyses on two of its subunits, FtsHi1 and FtsHi2. We isolated cDNA clones encoding FtsHi1 and FtsHi2 preproteins to perform in vitro import experiments in order to determine the exact size of each mature protein. We also generated antibodies against the C-termini of the proteins, i.e., where their ATPase domains reside. Protease treatments and alkaline and high-salt extractions of chloroplasts with imported and endogenous proteins revealed that FtsHi1 is an integral membrane protein with its C-terminal portion located in the intermembrane space of the envelope, not the stroma, whereas FtsHi2 is a soluble protein in the stroma. We further complemented an FtsHi1-knockout mutant with a C-terminally tagged FtsHi1 and obtained identical results for topological analyses. Our data indicate that the model of a single membrane-anchored pulling motor at the stromal side of the inner membrane needs to be revised and suggest that the Ycf2-FtsHi complex may have additional functions.
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Affiliation(s)
- Chia-Yun Chang
- Institute of Molecular Biology, Academia Sinica, Taipei11529, Taiwan
| | - Lih-Jen Chen
- Institute of Molecular Biology, Academia Sinica, Taipei11529, Taiwan
| | - Hsou-min Li
- Institute of Molecular Biology, Academia Sinica, Taipei11529, Taiwan
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14
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Abstract
Cellular membranes are essential components of all living organisms. They are composed of a complex mixture of lipids with diverse chemical structures and crucial biological functions. The dynamic and heterogeneous nature of cellular membranes presents a challenge for studying their biophysical properties and organization in vivo. Raman imaging, particularly coherent Raman scattering techniques such as stimulated Raman scattering (SRS) microscopy, have emerged as powerful tools for studying cellular membranes with high spatial and temporal resolution and minimal perturbation. In this Review, we discuss the scientific importance and technical challenges of characterizing membrane composition in cellular contexts and how the advances of Raman imaging can provide unique insights into membrane phase behavior and organization. We also highlight recent applications of Raman imaging in studying cellular membranes and implications in diseases. In particular, the discovery of phase separation and a solid-phase intracellular membrane on endoplasmic reticulum is reviewed in detail, shedding light on the biology of lipotoxicity.
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Affiliation(s)
- Yihui Shen
- Chemistry and Lewis Sigler Institute of Genomics, Princeton University, Princeton, New Jersey 08540, United States
| | - Lu Wei
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Wei Min
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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15
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Abstract
Peroxisomes are central metabolic organelles whose maturation and function depend on efficient and accurate targeting of peroxisomal membrane proteins (PMPs). Ultrastructural imaging of the PMPs is a quite difficult task as it requires high spatial and temporal resolution. Further, the spatial resolution of conventional light microscopy is limited due to the diffraction of light. However, recent methodological developments in super resolution microscopy showed us to access the nanoscale regimes spatially allowing to elucidate the membrane structures of cell organelles. In this chapter, we present protocols used in our laboratory for the super-resolution imaging of the peroxisomal membrane protein 14 (PEX14p) by direct stochastic optical reconstruction microscopy (dSTORM).
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Affiliation(s)
- Teresa Klein
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, Julius-Maximilians-University Wurzburg, Würzburg, Germany
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16
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Kustigian L, Gong X, Gai W, Thongchol J, Zhang J, Puchalla J, Carr CM, Rye HS. GTP-stimulated membrane fission by the N-BAR protein AMPH-1. Traffic 2023; 24:34-47. [PMID: 36435193 PMCID: PMC9825645 DOI: 10.1111/tra.12875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 10/24/2022] [Accepted: 11/19/2022] [Indexed: 11/28/2022]
Abstract
Membrane-enclosed transport carriers sort biological molecules between stations in the cell in a dynamic process that is fundamental to the physiology of eukaryotic organisms. While much is known about the formation and release of carriers from specific intracellular membranes, the mechanism of carrier formation from the recycling endosome, a compartment central to cellular signaling, remains to be resolved. In Caenorhabditis elegans, formation of transport carriers from the recycling endosome requires the dynamin-like, Eps15-homology domain (EHD) protein, RME-1, functioning with the Bin/Amphiphysin/Rvs (N-BAR) domain protein, AMPH-1. Here we show, using a free-solution single-particle technique known as burst analysis spectroscopy (BAS), that AMPH-1 alone creates small, tubular-vesicular products from large, unilamellar vesicles by membrane fission. Membrane fission requires the amphipathic H0 helix of AMPH-1 and is slowed in the presence of RME-1. Unexpectedly, AMPH-1-induced membrane fission is stimulated in the presence of GTP. Furthermore, the GTP-stimulated membrane fission activity seen for AMPH-1 is recapitulated by the heterodimeric N-BAR amphiphysin protein from yeast, Rvs161/167p, strongly suggesting that GTP-stimulated membrane fission is a general property of this important class of N-BAR proteins.
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Affiliation(s)
- Lauren Kustigian
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, 77845, USA
- Current address: GlaxoSmithKline, 1250 South Collegeville Rd., Collegeville, Pennsylvania 19426, USA
| | - Xue Gong
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, 77845, USA
| | - Wei Gai
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, 77845, USA
| | - Jirapat Thongchol
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, 77845, USA
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, 77845, USA
| | - Jason Puchalla
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Chavela M. Carr
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, 77845, USA
| | - Hays S. Rye
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, 77845, USA
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17
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Gardner AP, Barbieri JT, Pellett S. How Botulinum Neurotoxin Light Chain A1 Maintains Stable Association with the Intracellular Neuronal Plasma Membrane. Toxins (Basel) 2022; 14:toxins14120814. [PMID: 36548711 PMCID: PMC9783275 DOI: 10.3390/toxins14120814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022] Open
Abstract
Botulinum neurotoxin serotype A (BoNT/A) is the most potent protein toxin for humans and is utilized as a therapy for numerous neurologic diseases. BoNT/A comprises a catalytic Light Chain (LC/A) and a Heavy Chain (HC/A) and includes eight subtypes (BoNT/A1-/A8). Previously we showed BoNT/A potency positively correlated with stable localization on the intracellular plasma membrane and identified a low homology domain (amino acids 268-357) responsible for LC/A1 stable co-localization with SNAP-25 on the plasma membrane, while LC/A3 was present in the cytosol of Neuro2A cells. In the present study, steady-state- and live-imaging of a cytosolic LC/A3 derivative (LC/A3V) engineered to contain individual structural elements of the A1 LDH showed that a 59 amino acid region (275-334) termed the MLD was sufficient to direct LC/A3V from the cytosol to the plasma membrane co-localized with SNAP-25. Informatics and experimental validation of the MLD-predicted R1 region (an α-helix, residues 275-300) and R2 region (a loop, α-helix, loop, residues 302-334) both contribute independent steps to the stable co-localization of LC/A1 with SNAP-25 on the plasma membrane of Neuro-2A cells. Understanding how these structural elements contribute to the overall association of LC/A1 on the plasma membrane may identify the molecular basis for the LC contribution of BoNT/A1 to high potency.
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Affiliation(s)
- Alexander P. Gardner
- Microbiology and Immunology, Medical College, Wisconsin 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Joseph T. Barbieri
- Microbiology and Immunology, Medical College, Wisconsin 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
- Correspondence: (J.T.B.); (S.P.)
| | - Sabine Pellett
- Department of Bacteriology, Microbial Sciences Building, University of Wisconsin-Madison, 1550 Linden Dr., Madison, WI 53706, USA
- Correspondence: (J.T.B.); (S.P.)
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18
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Schäfer K, Engstler C, Dischinger K, Carrie C. Assessment of Mitochondrial Protein Topology and Membrane Insertion. Methods Mol Biol 2022; 2363:165-181. [PMID: 34545493 DOI: 10.1007/978-1-0716-1653-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Analyzing the membrane integrity and topology of a mitochondrial protein is essential for truly understanding its function. In this chapter, we demonstrate how to analyze mitochondrial membrane proteins using both an immunological-based assay and an in vivo self-assembling GFP approach. First, immunological approaches to investigate the solubility or membrane association of a protein within mitochondria are described. With this method, we demonstrate how the topology of soluble domains of a membrane-integrated protein can be determined. Using protein-specific antibodies, the localization of the soluble domains of a protein are analyzed by a proteolytic-cleavage approach using proteinase K in mitochondria, outer membrane-ruptured mitochondria, and solubilized mitochondrial membranes. In a second approach, we determine the topology of plant mitochondrial proteins using an in vivo self-assembling GFP localization approach.
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Affiliation(s)
- Kerstin Schäfer
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Carina Engstler
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Korbinian Dischinger
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Chris Carrie
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.
- Department of Biotechnology, University of Verona, Verona, Italy.
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19
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Romanov GA, Schmülling T. Opening Doors for Cytokinin Trafficking at the ER Membrane. Trends Plant Sci 2021; 26:305-308. [PMID: 33618985 DOI: 10.1016/j.tplants.2021.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
The recent discovery of cytokinin transporters in the endoplasmic reticulum (ER) membrane provides a missing link to understand cellular cytokinin trafficking and signaling. Along with cytokinin receptors and metabolic enzymes previously found in the ER, these transporters complement the ER-confined infrastructure required for cytokinin signal generation and modulation.
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Affiliation(s)
- Georgy A Romanov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia.
| | - Thomas Schmülling
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany.
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20
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Bosmani C, Leuba F, Hanna N, Bach F, Burdet F, Pagni M, Hagedorn M, Soldati T. Vacuolins and myosin VII are required for phagocytic uptake and phagosomal membrane recycling in Dictyostelium discoideum. J Cell Sci 2020; 133:jcs242974. [PMID: 32482795 DOI: 10.1242/jcs.242974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/18/2020] [Indexed: 12/17/2022] Open
Abstract
Flotillins are lipid raft residents involved in membrane trafficking and recycling of plasma membrane proteins. Dictyostelium discoideum uses phagocytosis to kill, digest and feed on bacteria. It possesses three flotillin-like vacuolins that are strongly associated with membranes and that gradually accumulate on maturing phagosomes. Absence of vacuolins reduced adhesion and particle recognition resulting in a drastic reduction in the uptake of various types of particles. This was caused by a block in the recycling of plasma membrane components and the absence of their specific cortex-associated proteins. In addition, absence of vacuolins also impaired phagolysosome biogenesis, without significantly impacting killing and digestion of a range of bacteria. Strikingly, both absence and overexpression of vacuolins induced a strong downregulation of myosin VII (also known as MyoI) expression, as well as its binding partner talin A. Episomal expression of myosin VII fully rescued defects in uptake and adhesion but not in phagosome maturation. These results suggest a dual role for vacuolins: a novel mechanism involving membrane microdomains and myosin VII-talin A in clustering phagosomal receptors and adhesion molecules at the plasma membrane, and a role in phagolysosomal biogenesis.
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Affiliation(s)
- Cristina Bosmani
- Départment de Biochimie, Faculté des Sciences, Université de Genève, CH-1205 Geneva, Switzerland
| | - Florence Leuba
- Départment de Biochimie, Faculté des Sciences, Université de Genève, CH-1205 Geneva, Switzerland
| | - Nabil Hanna
- Départment de Biochimie, Faculté des Sciences, Université de Genève, CH-1205 Geneva, Switzerland
| | - Frauke Bach
- Section Parasitology, Bernhard Nocht Institute for Tropical Medicine, D-20359 Hamburg, Germany
| | - Frédéric Burdet
- Vital-IT, Swiss Institute of Bioinformatics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Marco Pagni
- Vital-IT, Swiss Institute of Bioinformatics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Monica Hagedorn
- Section Parasitology, Bernhard Nocht Institute for Tropical Medicine, D-20359 Hamburg, Germany
| | - Thierry Soldati
- Départment de Biochimie, Faculté des Sciences, Université de Genève, CH-1205 Geneva, Switzerland
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21
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Bastin G, Dissanayake K, Langburt D, Tam ALC, Lee SH, Lachhar K, Heximer SP. RGS4 controls Gαi3-mediated regulation of Bcl-2 phosphorylation on TGN38-containing intracellular membranes. J Cell Sci 2020; 133:jcs241034. [PMID: 32501280 DOI: 10.1242/jcs.241034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 05/05/2020] [Indexed: 08/31/2023] Open
Abstract
Intracellular pools of the heterotrimeric G-protein α-subunit Gαi3 (encoded by GNAI3) have been shown to promote growth factor signaling, while at the same time inhibiting the activation of JNK and autophagic signaling following nutrient starvation. The precise molecular mechanisms linking Gαi3 to both stress and growth factor signaling remain poorly understood. Importantly, JNK-mediated phosphorylation of Bcl-2 was previously found to activate autophagic signaling following nutrient deprivation. Our data shows that activated Gαi3 decreases Bcl-2 phosphorylation, whereas inhibitors of Gαi3, such as RGS4 and AGS3 (also known as GPSM1), markedly increase the levels of phosphorylated Bcl-2. Manipulation of the palmitoylation status and intracellular localization of RGS4 suggests that Gαi3 modulates phosphorylated Bcl-2 levels and autophagic signaling from discreet TGN38 (also known as TGOLN2)-labeled vesicle pools. Consistent with an important role for these molecules in normal tissue responses to nutrient deprivation, increased Gαi signaling within nutrient-starved adrenal glands from RGS4-knockout mice resulted in a dramatic abrogation of autophagic flux, compared to wild-type tissues. Together, these data suggest that the activity of Gαi3 and RGS4 from discreet TGN38-labeled vesicle pools are critical regulators of autophagic signaling that act via their ability to modulate phosphorylation of Bcl-2.
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Affiliation(s)
- Guillaume Bastin
- Ted Rogers Centre for Heart Research, Translational Biology and Engineering Program, 661 University Ave. 14th Floor, Toronto, ON, M5G 1M1, Canada
- Heart and Stroke/Richard Lewar Centre of Excellence in Cardiovascular Research, Room 303, C. David Naylor Building, 6 Queen's Park Crescent West, Toronto, ON, M5S 3H2, Canada
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Kaveesh Dissanayake
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Dylan Langburt
- Ted Rogers Centre for Heart Research, Translational Biology and Engineering Program, 661 University Ave. 14th Floor, Toronto, ON, M5G 1M1, Canada
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Alex L C Tam
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Shin-Haw Lee
- Ted Rogers Centre for Heart Research, Translational Biology and Engineering Program, 661 University Ave. 14th Floor, Toronto, ON, M5G 1M1, Canada
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Karanjit Lachhar
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Scott P Heximer
- Ted Rogers Centre for Heart Research, Translational Biology and Engineering Program, 661 University Ave. 14th Floor, Toronto, ON, M5G 1M1, Canada
- Heart and Stroke/Richard Lewar Centre of Excellence in Cardiovascular Research, Room 303, C. David Naylor Building, 6 Queen's Park Crescent West, Toronto, ON, M5S 3H2, Canada
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
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22
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Gronnier J, Legrand A, Loquet A, Habenstein B, Germain V, Mongrand S. Mechanisms governing subcompartmentalization of biological membranes. Curr Opin Plant Biol 2019; 52:114-123. [PMID: 31546133 DOI: 10.1016/j.pbi.2019.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/14/2019] [Accepted: 08/20/2019] [Indexed: 06/10/2023]
Abstract
Membranes show a tremendous variety of lipids and proteins operating biochemistry, transport and signalling. The dynamics and the organization of membrane constituents are regulated in space and time to execute precise functions. Our understanding of the molecular mechanisms that shape and govern membrane subcompartmentalization and inter-organelle contact sites still remains limited. Here, we review some reported mechanisms implicated in regulating plant membrane domains including those of plasma membrane, plastids, mitochondria and endoplasmic reticulum. Finally, we discuss several state-of-the-art methods that allow nowadays researchers to decipher the architecture of these structures at the molecular and atomic level.
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Affiliation(s)
- Julien Gronnier
- Department of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
| | - Anthony Legrand
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, 33140 Villenave d'Ornon, France; Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR5248 CBMN), IECB, CNRS, Université de Bordeaux, Institut Polytechnique de Bordeaux, All, Geoffroy Saint-Hilaire, Pessac, France
| | - Antoine Loquet
- Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR5248 CBMN), IECB, CNRS, Université de Bordeaux, Institut Polytechnique de Bordeaux, All, Geoffroy Saint-Hilaire, Pessac, France
| | - Birgit Habenstein
- Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR5248 CBMN), IECB, CNRS, Université de Bordeaux, Institut Polytechnique de Bordeaux, All, Geoffroy Saint-Hilaire, Pessac, France
| | - Véronique Germain
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, 33140 Villenave d'Ornon, France
| | - Sébastien Mongrand
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, 33140 Villenave d'Ornon, France.
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23
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Karnkowska A, Treitli SC, Brzoň O, Novák L, Vacek V, Soukal P, Barlow LD, Herman EK, Pipaliya SV, Pánek T, Žihala D, Petrželková R, Butenko A, Eme L, Stairs CW, Roger AJ, Eliáš M, Dacks JB, Hampl V. The Oxymonad Genome Displays Canonical Eukaryotic Complexity in the Absence of a Mitochondrion. Mol Biol Evol 2019; 36:2292-2312. [PMID: 31387118 PMCID: PMC6759080 DOI: 10.1093/molbev/msz147] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The discovery that the protist Monocercomonoides exilis completely lacks mitochondria demonstrates that these organelles are not absolutely essential to eukaryotic cells. However, the degree to which the metabolism and cellular systems of this organism have adapted to the loss of mitochondria is unknown. Here, we report an extensive analysis of the M. exilis genome to address this question. Unexpectedly, we find that M. exilis genome structure and content is similar in complexity to other eukaryotes and less "reduced" than genomes of some other protists from the Metamonada group to which it belongs. Furthermore, the predicted cytoskeletal systems, the organization of endomembrane systems, and biosynthetic pathways also display canonical eukaryotic complexity. The only apparent preadaptation that permitted the loss of mitochondria was the acquisition of the SUF system for Fe-S cluster assembly and the loss of glycine cleavage system. Changes in other systems, including in amino acid metabolism and oxidative stress response, were coincident with the loss of mitochondria but are likely adaptations to the microaerophilic and endobiotic niche rather than the mitochondrial loss per se. Apart from the lack of mitochondria and peroxisomes, we show that M. exilis is a fully elaborated eukaryotic cell that is a promising model system in which eukaryotic cell biology can be investigated in the absence of mitochondria.
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Affiliation(s)
- Anna Karnkowska
- Department of Parasitology, BIOCEV, Faculty of Science, Charles University, Vestec, Czech Republic
- Department of Molecular Phylogenetics and Evolution, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Sebastian C Treitli
- Department of Parasitology, BIOCEV, Faculty of Science, Charles University, Vestec, Czech Republic
| | - Ondřej Brzoň
- Department of Parasitology, BIOCEV, Faculty of Science, Charles University, Vestec, Czech Republic
| | - Lukáš Novák
- Department of Parasitology, BIOCEV, Faculty of Science, Charles University, Vestec, Czech Republic
| | - Vojtěch Vacek
- Department of Parasitology, BIOCEV, Faculty of Science, Charles University, Vestec, Czech Republic
| | - Petr Soukal
- Department of Parasitology, BIOCEV, Faculty of Science, Charles University, Vestec, Czech Republic
| | - Lael D Barlow
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Emily K Herman
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Shweta V Pipaliya
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Tomáš Pánek
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - David Žihala
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Romana Petrželková
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Anzhelika Butenko
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Laura Eme
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Canada
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Courtney W Stairs
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Canada
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Andrew J Roger
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Canada
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
- Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Joel B Dacks
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Vladimír Hampl
- Department of Parasitology, BIOCEV, Faculty of Science, Charles University, Vestec, Czech Republic
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24
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Ryan VH, Fawzi NL. Physiological, Pathological, and Targetable Membraneless Organelles in Neurons. Trends Neurosci 2019; 42:693-708. [PMID: 31493925 PMCID: PMC6779520 DOI: 10.1016/j.tins.2019.08.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 07/03/2019] [Accepted: 08/05/2019] [Indexed: 12/20/2022]
Abstract
Neurons require unique subcellular compartmentalization to function efficiently. Formed from proteins and RNAs through liquid-liquid phase separation, membraneless organelles (MLOs) have emerged as one way in which cells form distinct, specialized compartments in the absence of lipid membranes. We first discuss MLOs that are common to many cell types as well as those that are specific to neurons. Interestingly, many proteins associated with neurodegenerative disease are found in MLOs, particularly in stress and transport granules. We next review possible links between neurodegeneration and MLOs, and the hypothesis that the protein and RNA inclusions formed in disease are related to the functional complexes occurring inside these MLOs. Finally, we discuss the hypothesis that protein post-translational modifications (PTMs), which can alter phase separation, can modulate MLO formation and provide potential new therapeutic strategies for currently untreatable neurodegenerative diseases.
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Affiliation(s)
- Veronica H Ryan
- Neuroscience Graduate Program, Brown University, Providence, RI 02912, USA
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02912, USA.
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25
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Parsons HT, Stevens TJ, McFarlane HE, Vidal-Melgosa S, Griss J, Lawrence N, Butler R, Sousa MML, Salemi M, Willats WGT, Petzold CJ, Heazlewood JL, Lilley KS. Separating Golgi Proteins from Cis to Trans Reveals Underlying Properties of Cisternal Localization. Plant Cell 2019; 31:2010-2034. [PMID: 31266899 PMCID: PMC6751122 DOI: 10.1105/tpc.19.00081] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 06/03/2019] [Accepted: 06/29/2019] [Indexed: 05/15/2023]
Abstract
The order of enzymatic activity across Golgi cisternae is essential for complex molecule biosynthesis. However, an inability to separate Golgi cisternae has meant that the cisternal distribution of most resident proteins, and their underlying localization mechanisms, are unknown. Here, we exploit differences in surface charge of intact cisternae to perform separation of early to late Golgi subcompartments. We determine protein and glycan abundance profiles across the Golgi; over 390 resident proteins are identified, including 136 new additions, with over 180 cisternal assignments. These assignments provide a means to better understand the functional roles of Golgi proteins and how they operate sequentially. Protein and glycan distributions are validated in vivo using high-resolution microscopy. Results reveal distinct functional compartmentalization among resident Golgi proteins. Analysis of transmembrane proteins shows several sequence-based characteristics relating to pI, hydrophobicity, Ser abundance, and Phe bilayer asymmetry that change across the Golgi. Overall, our results suggest that a continuum of transmembrane features, rather than discrete rules, guide proteins to earlier or later locations within the Golgi stack.
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Affiliation(s)
- Harriet T Parsons
- Department of Biochemistry, Cambridge University, Cambridge, CB2 1QW, United Kingdom
- Department of Plant and Environmental Sciences, Copenhagen University, 1871 Frederiksberg C, Denmark
| | - Tim J Stevens
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, United Kingdom
| | - Heather E McFarlane
- School of Biosciences, University of Melbourne, Parkville VIC 3052, , Australia
| | - Silvia Vidal-Melgosa
- Department of Plant and Environmental Sciences, Copenhagen University, 1871 Frederiksberg C, Denmark
| | - Johannes Griss
- Department of Dermatology, Medical University of Vienna, 1090 Vienna, Austria
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, CB10 1SD, United Kingdom
| | - Nicola Lawrence
- The Wellcome Trust and Cancer Research UK Gurdon Institute, Cambridge University, Cambridge CB2 1QN, United Kingdom
| | - Richard Butler
- The Wellcome Trust and Cancer Research UK Gurdon Institute, Cambridge University, Cambridge CB2 1QN, United Kingdom
| | - Mirta M L Sousa
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Michelle Salemi
- Proteomics Core Facility, University of California, Davis, California 95616
| | - William G T Willats
- Department of Plant and Environmental Sciences, Copenhagen University, 1871 Frederiksberg C, Denmark
| | - Christopher J Petzold
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Joshua L Heazlewood
- School of Biosciences, University of Melbourne, Parkville VIC 3052, , Australia
| | - Kathryn S Lilley
- Department of Biochemistry, Cambridge University, Cambridge, CB2 1QW, United Kingdom
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26
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Tsai P, Lin TY, Cheng SL, Sun HY, Chen SF, Young KC. Differential dynamics of hepatic protein expressions with long-term cultivated hepatitis C virus infection. J Microbiol Immunol Infect 2019; 53:715-723. [PMID: 30837187 DOI: 10.1016/j.jmii.2019.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 12/28/2018] [Accepted: 01/16/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND The liver maintains blood chemical homeostasis by active uptake and secretion through endocytosis, exocytosis, and intracellular trafficking between the plasma and intracellular membranes. Hepatitis C virus (HCV) infection affects the host membrane architecture and might thus impair the regulation of the cellular transportation machinery. Additionally, the hepatic expressions of differential protein dynamics with long-term HCV infection remain fully recover. METHODS In this study, comparative proteomic analysis was performed in HCV-infected and mock-control Huh7 cells according to the viral dynamics of exponential, plateau, declined, and silencing phases at the acute stage, and the chronic stage. The proteins with <0.8-fold and ≥1.25-fold changes in expression were analyzed using functional pathway clustering prediction. RESULTS The combined experimental repetitions identified full-spectrum cellular proteins in each of 5 sample sets from acute exponential, plateau, declined, and silencing phases, and the chronic stage. The clustering results revealed that HCV infection might differentiate regulatory pathways involving extracellular exosome, cadherin, melanosome, and RNA binding. Overall host proteins in HCV-infected cells exhibited kinetic pattern 1, in which cellular expression was downregulated from the acute exponential to plateau phases, reached a nadir, and was then elevated at the chronic stage. The proteins involved in the membrane-budding pathway exhibited kinetic pattern 2, in which their expressions were distinctly downregulated at the chronic stage. CONCLUSION The current comparative proteomics revealed the differential regulatory effects of HCV infection on host intracellular transport functional pathways, which might contribute to the pathogenic mechanisms of HCV in hepatocytes that sustain long-term infection.
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Affiliation(s)
- Peiju Tsai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Tze-Yu Lin
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
| | - Shiang-Lin Cheng
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hung-Yu Sun
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Sung-Fang Chen
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan.
| | - Kung-Chia Young
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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27
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Abstract
The outer membrane and the inner membrane of the chloroplast envelope, also called OEM and IEM, have distinct functions connected with chloroplast biogenesis and chloroplast communication with the rest of the cell. Here we describe a method for the isolation of these membranes starting from intact chloroplast preparations, with two alternative procedures based on the starting material. One was developed from spinach leaves, the other one from pea leaves. The two procedures differ by the means that are used to isolate and rupture chloroplasts and to liberate each membrane.
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Affiliation(s)
- Maryse A Block
- Laboratoire de Physiologie Cellulaire et Végétale, Centre National de la Recherche Scientifique, Institut National Recherche Agronomique, Commissariat à l'Energie Atomique et aux Energies Alternatives, CEA Grenoble, UMR5168, Université Grenoble Alpes, Grenoble, France.
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28
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Abstract
Free-flow electrophoresis (FFE) is a technique for separation of proteins, peptides, organelles, and cells. With zone electrophoresis (ZE-FFE), organelles are separated according to surface charge. The ER is the only remaining major cellular compartment in Arabidopsis not to have been isolated using density centrifugation, immune-isolation, or any other method previously applied to purification of plant membranes. By using continuous-flow electrophoresis ER vesicles of similar surface charge, which may have been fragmented during cell lysis, can be focused. A large portion of these vesicles are of sufficiently different surface charge that separation from the majority of Golgi and other contaminants is possible. Here we adapt an earlier ZE-FFE Golgi isolation protocol for the isolation of highly pure ER vesicles and for tracking the migration of peripheral ER vesicles. Isolating ER vesicles of homogenous surface charge allows multi-'omic analyses to be performed on the ER. This facilitates investigations into structure-function relationships within the ER.
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Affiliation(s)
- Harriet T Parsons
- Biochemistry Department, Cambridge University, Cambridge, CB2 1QJ, UK.
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29
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Abstract
During the last decades, increasing evidence indicated that subcellular organelles do not exist as autarkic units but instead communicate constantly and extensively with each other in various ways. Some communication, for example, the exchange of small molecules, requires the marked convergence of two distinct organelles for a certain period of time. The cross talk between endoplasmic reticulum (ER) and mitochondria, two subcellular organelles of utmost importance for cellular bioenergetics and protein homeostasis, has been increasingly investigated under the last years. This development was significantly driven by the establishment of optimized subcellular fractionation techniques. In this chapter, we will describe and critically discuss the currently used protocol for the isolation of the membrane fraction containing mitochondria-associated membranes (MAM).
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Affiliation(s)
- Bernadette Schreiner
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society,, Karolinska Institutet, SE, -141 57, Huddinge, Sweden.
| | - Maria Ankarcrona
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society,, Karolinska Institutet, SE, -141 57, Huddinge, Sweden
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30
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Hagstrom D, Ma C. Biochemically characterizing the subcellular localization of peroxisomal proteins by fractionation, protease protection, and carbonate extraction. Methods Mol Biol 2014; 1163:175-81. [PMID: 24841306 DOI: 10.1007/978-1-4939-0799-1_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Traditional biochemical approaches, as well as the complementary methods of living cell fluorescence microscopy and immunofluorescence microscopy, can serve to characterize the subcellular localization of proteins and organelles. This chapter describes methods for isolation of crude organelle fractions from methanol- or oleate-grown Pichia pastoris, followed by protease protection and carbonate extraction assays to dissect the subcellular localization of peroxisomal matrix and membrane proteins. These biochemical tools can be used to analyze the targeting efficiency of proteins to the peroxisome membrane and matrix, as well as the topology of membrane proteins.
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Affiliation(s)
- Danielle Hagstrom
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093-0322, USA
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31
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Asleh R, Nakhoul FM, Miller-Lotan R, Awad H, Farbstein D, Levy NS, Nakhoul N, Iancu TC, Manov I, Laue M, Traber MG, Lebold KM, Levy AP. Poor lysosomal membrane integrity in proximal tubule cells of haptoglobin 2-2 genotype mice with diabetes mellitus. Free Radic Biol Med 2012; 53:779-86. [PMID: 22749805 PMCID: PMC3600120 DOI: 10.1016/j.freeradbiomed.2012.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/05/2012] [Accepted: 06/11/2012] [Indexed: 10/28/2022]
Abstract
The haptoglobin (Hp) genotype is a major determinant of progression of nephropathy in individuals with diabetes mellitus (DM). The major function of the Hp protein is to bind and modulate the fate of extracorpuscular hemoglobin and its iron cargo. We have previously demonstrated an interaction between the Hp genotype and the DM on the accumulation of iron in renal proximal tubule cells. The primary objective of this study was to determine the intracellular localization of this iron in the proximal tubule cell and to assess its potential toxicity. Transmission electron microscopy demonstrated a marked accumulation of electron-dense deposits in the lysosomes of proximal tubules cells in Hp 2-2 DM mice. Energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy were used to perform elemental analysis of these deposits and demonstrated that these deposits were iron rich. These deposits were associated with lysosomal membrane lipid peroxidation and loss of lysosomal membrane integrity. Vitamin E administration to Hp 2-2 DM mice resulted in a significant decrease in both intralysosomal iron-induced oxidation and lysosomal destabilization. Iron-induced renal tubular injury may play a major role in the development of diabetic nephropathy and may be a target for slowing the progression of renal disease.
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Affiliation(s)
- Rabea Asleh
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 1 Efron St. Bat Galim, P.O.B. 9649, Haifa, Israel
| | - Farid M. Nakhoul
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 1 Efron St. Bat Galim, P.O.B. 9649, Haifa, Israel
- Nephrology Department, Baruch-Padeh Poryia Medical Center, Bar Ilan University Faculty of Medicine, Lower Galilee, 15208, Poryia, Israel
- Corresponding author at: Poryia Medical Center, Bar Ilan University Faculty of Medicine, Poryia, Israel. fax: 972 4 6652587
| | - Rachel Miller-Lotan
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 1 Efron St. Bat Galim, P.O.B. 9649, Haifa, Israel
| | - Hoda Awad
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 1 Efron St. Bat Galim, P.O.B. 9649, Haifa, Israel
| | - Dan Farbstein
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 1 Efron St. Bat Galim, P.O.B. 9649, Haifa, Israel
| | - Nina S. Levy
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 1 Efron St. Bat Galim, P.O.B. 9649, Haifa, Israel
| | - Nakhoul Nakhoul
- Nephrology Department, Baruch-Padeh Poryia Medical Center, Bar Ilan University Faculty of Medicine, Lower Galilee, 15208, Poryia, Israel
| | - Theodore C. Iancu
- Pediatric Research and Electron Microscopy Unit, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 1 Efron St. Bat Galim, P.O.B. 9649, Haifa, Israel
| | - Irena Manov
- Pediatric Research and Electron Microscopy Unit, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 1 Efron St. Bat Galim, P.O.B. 9649, Haifa, Israel
| | - Michael Laue
- Robert Koch Institute, Nordufer 20, 13353, Berlin, Germany
| | - Maret G. Traber
- Linus Pauling Institute, Oregon State University, 307 Linus Pauling Science Center, Corvalis, OR, USA
| | - Katie M. Lebold
- Linus Pauling Institute, Oregon State University, 307 Linus Pauling Science Center, Corvalis, OR, USA
| | - Andrew P. Levy
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, 1 Efron St. Bat Galim, P.O.B. 9649, Haifa, Israel
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32
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Abstract
Phagocytosis is used by macrophages, dendritic cells and neutrophils to capture and destroy pathogens and particulate antigens. Although localized assembly of actin filaments is the driving force for particle internalization, exocytosis of intracellular compartments, and in particular endocytic compartments, has been shown recently to be required for the early steps of phagosome formation. Here we report on the different compartments undergoing exocytosis during phagocytosis, with a special focus on late endosomes. We then compare this process with secretion from lysosomes or lysosome-related organelles in specialized cells. Finally, we discuss how some of the molecular mechanisms responsible for lysosome-related organelle secretion could also be implicated in phagosome formation.
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Affiliation(s)
- Virginie Braun
- Membrane and Cytoskeleton Dynamics group, Institut Curie, CNRS UMR144, 75005 Paris, France
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33
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Ray S, Taylor M, Burlingame M, Tatulian SA, Teter K. Modulation of toxin stability by 4-phenylbutyric acid and negatively charged phospholipids. PLoS One 2011; 6:e23692. [PMID: 21887297 PMCID: PMC3161752 DOI: 10.1371/journal.pone.0023692] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 07/22/2011] [Indexed: 12/20/2022] Open
Abstract
AB toxins such as ricin and cholera toxin (CT) consist of an enzymatic A domain and a receptor-binding B domain. After endocytosis of the surface-bound toxin, both ricin and CT are transported by vesicle carriers to the endoplasmic reticulum (ER). The A subunit then dissociates from its holotoxin, unfolds, and crosses the ER membrane to reach its cytosolic target. Since protein unfolding at physiological temperature and neutral pH allows the dissociated A chain to attain a translocation-competent state for export to the cytosol, the underlying regulatory mechanisms of toxin unfolding are of paramount biological interest. Here we report a biophysical analysis of the effects of anionic phospholipid membranes and two chemical chaperones, 4-phenylbutyric acid (PBA) and glycerol, on the thermal stabilities and the toxic potencies of ricin toxin A chain (RTA) and CT A1 chain (CTA1). Phospholipid vesicles that mimic the ER membrane dramatically decreased the thermal stability of RTA but not CTA1. PBA and glycerol both inhibited the thermal disordering of RTA, but only glycerol could reverse the destabilizing effect of anionic phospholipids. In contrast, PBA was able to increase the thermal stability of CTA1 in the presence of anionic phospholipids. PBA inhibits cellular intoxication by CT but not ricin, which is explained by its ability to stabilize CTA1 and its inability to reverse the destabilizing effect of membranes on RTA. Our data highlight the toxin-specific intracellular events underlying ER-to-cytosol translocation of the toxin A chain and identify a potential means to supplement the long-term stabilization of toxin vaccines.
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Affiliation(s)
- Supriyo Ray
- Department of Physics, University of Central Florida, Orlando, Florida, United States of America
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Michael Taylor
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Mansfield Burlingame
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
- Lake Brantley High School, Altamonte Springs, Florida, United States of America
| | - Suren A. Tatulian
- Department of Physics, University of Central Florida, Orlando, Florida, United States of America
| | - Ken Teter
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
- * E-mail:
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34
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Affiliation(s)
- Ann H Erickson
- Department of Biochemisty and Biophysics, University of North Carolina, Chapel Hill, USA
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35
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Ishihara N. [Regulation and physiological roles of mitochondrial dynamics]. Seikagaku 2010; 82:39-42. [PMID: 20169996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- Naotada Ishihara
- Department of Physiology and Cell Biology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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36
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Aquil S, Husaini AM, Abdin MZ, Rather GM. Overexpression of the HMG-CoA reductase gene leads to enhanced artemisinin biosynthesis in transgenic Artemisia annua plants. Planta Med 2009; 75:1453-8. [PMID: 19551613 DOI: 10.1055/s-0029-1185775] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
An effective and affordable treatment against malaria is still a challenge for medicine. Most contemporary drugs either are too expensive to produce or are not effective against resistant strains of the malaria parasite Plasmodium falciparum. The plant Artemisia annua L. is the source of artemisinin, an effective drug against malaria for which no resistant strains of the bacterium have been reported. However, the artemisinin content of A. annua is very low, which makes its production expensive. Here we report the use of transgenic technology to increase the artemisinin content of A. annua. We report the production of transgenic plants of A. annua into which we transferred 3-hydroxy-3-methylglutaryl CoA reductase (HMGR) gene from Catharanthus roseus (L.) G. Don using Agrobacterium-mediated gene transfer technology. Transgene integration and copy number were assessed by PCR and Southern hybridization, which confirmed the stable integration of multiple copies of the transgene in 7 different transgenic lines of A. annua. The leaf tissue of three of the A. annua transgenic lines possessed significantly higher HMGR activity compared with wild-type controls, and this activity was associated exclusively with microsomal membranes. The artemisinin content of the shoots of one of the transgenic lines depicted an increase of 22.5 % artemisinin content compared with wild-type control A. annua plants.
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Affiliation(s)
- Samina Aquil
- Centre for Transgenic Plant Development, Department of Biotechnology, Jamia Hamdard, New Delhi, India
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37
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Ham JH, Majerczak DR, Nomura K, Mecey C, Uribe F, He SY, Mackey D, Coplin DL. Multiple activities of the plant pathogen type III effector proteins WtsE and AvrE require WxxxE motifs. Mol Plant Microbe Interact 2009; 22:703-12. [PMID: 19445595 PMCID: PMC2748107 DOI: 10.1094/mpmi-22-6-0703] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The broadly conserved AvrE-family of type III effectors from gram-negative plant-pathogenic bacteria includes important virulence factors, yet little is known about the mechanisms by which these effectors function inside plant cells to promote disease. We have identified two conserved motifs in AvrE-family effectors: a WxxxE motif and a putative C-terminal endoplasmic reticulum membrane retention/retrieval signal (ERMRS). The WxxxE and ERMRS motifs are both required for the virulence activities of WtsE and AvrE, which are major virulence factors of the corn pathogen Pantoea stewartii subsp. stewartii and the tomato or Arabidopsis pathogen Pseudomonas syringae pv. tomato, respectively. The WxxxE and the predicted ERMRS motifs are also required for other biological activities of WtsE, including elicitation of the hypersensitive response in nonhost plants and suppression of defense responses in Arabidopsis. A family of type III effectors from mammalian bacterial pathogens requires WxxxE and subcellular targeting motifs for virulence functions that involve their ability to mimic activated G-proteins. The conservation of related motifs and their necessity for the function of type III effectors from plant pathogens indicates that disturbing host pathways by mimicking activated host G-proteins may be a virulence mechanism employed by plant pathogens as well.
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Affiliation(s)
- Jong Hyun Ham
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, 43210
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210
| | - Doris R. Majerczak
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210
| | - Kinya Nomura
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824
| | - Christy Mecey
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824
| | - Francisco Uribe
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824
| | - Sheng-Yang He
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824
| | - David Mackey
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, 43210
| | - David L. Coplin
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210
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38
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Fourrier N, Bédard J, Lopez-Juez E, Barbrook A, Bowyer J, Jarvis P, Warren G, Thorlby G. A role for SENSITIVE TO FREEZING2 in protecting chloroplasts against freeze-induced damage in Arabidopsis. Plant J 2008; 55:734-45. [PMID: 18466306 DOI: 10.1111/j.1365-313x.2008.03549.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The sensitive to freezing2 (SFR2) gene has an important role in freezing tolerance in Arabidopsis thaliana. We show that homologous genes are present, and expressed, in a wide range of terrestrial plants, including species not able to tolerate freezing. Expression constructs derived from the cDNAs of a number of different plant species, including examples not tolerant to freezing, are able to complement the freezing sensitivity of the Arabidopsis sfr2 mutant. In Arabidopsis the SFR2 protein is localized to the chloroplast outer envelope membrane, as revealed by the analysis of transgenic plants expressing SFR2 fusions to GFP, by confocal microscopy, and by the immunological analysis of isolated chloroplasts treated with thermolysin protease. Moreover, the chloroplasts of the sfr2 mutant show clear evidence of rapid damage after a freezing episode, suggesting a role for SFR2 in the protection of the chloroplast.
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MESH Headings
- Amino Acid Sequence
- Arabidopsis/genetics
- Arabidopsis/physiology
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/physiology
- Chloroplasts/genetics
- Chloroplasts/physiology
- Freezing
- Genes, Plant
- Genes, Reporter
- Genetic Complementation Test
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/physiology
- Intracellular Membranes
- Microscopy, Confocal
- Microscopy, Electron, Transmission
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Phylogeny
- Plant Leaves/genetics
- Plant Leaves/physiology
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/physiology
- RNA, Plant/genetics
- Recombinant Proteins/genetics
- Sequence Alignment
- Sequence Analysis, Protein
- Sequence Homology, Amino Acid
- beta-Glucosidase/genetics
- beta-Glucosidase/physiology
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Affiliation(s)
- Nicolas Fourrier
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, UK
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39
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Garner AL, Chen G, Chen N, Sridhara V, Kolb JF, Swanson RJ, Beebe SJ, Joshi RP, Schoenbach KH. Ultrashort electric pulse induced changes in cellular dielectric properties. Biochem Biophys Res Commun 2007; 362:139-144. [PMID: 17706595 DOI: 10.1016/j.bbrc.2007.07.159] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Accepted: 07/31/2007] [Indexed: 11/22/2022]
Abstract
The interaction of nanosecond duration pulsed electric fields (nsPEFs) with biological cells, and the models describing this behavior, depend critically on the electrical properties of the cells being pulsed. Here, we used time domain dielectric spectroscopy to measure the dielectric properties of Jurkat cells, a malignant human T-cell line, before and after exposure to five 10ns, 150kV/cm electrical pulses. The cytoplasm and nucleoplasm conductivities decreased dramatically following pulsing, corresponding to previously observed rises in cell suspension conductivity. This suggests that electropermeabilization occurred, resulting in ion transport from the cell's interior to the exterior. A delayed decrease in cell membrane conductivity after the nsPEFs possibly suggests long-term ion channel damage or use dependence due to repeated membrane charging and discharging. This data could be used in models describing the phenomena at work.
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Affiliation(s)
- Allen L Garner
- Bioelectromagnetism Laboratory, Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109, USA; Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23510, USA.
| | - George Chen
- School of Electronics and Computer Science, University of Southampton, Southampton So17 1bj, UK
| | - Nianyong Chen
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23510, USA
| | - Viswanadham Sridhara
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529, USA
| | - Juergen F Kolb
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23510, USA; Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529, USA
| | - R James Swanson
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23510, USA; Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Stephen J Beebe
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23510, USA; Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA 23510, USA
| | - Ravindra P Joshi
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23510, USA; Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529, USA
| | - Karl H Schoenbach
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23510, USA; Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529, USA.
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40
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Higaki T, Goh T, Hayashi T, Kutsuna N, Kadota Y, Hasezawa S, Sano T, Kuchitsu K. Elicitor-induced cytoskeletal rearrangement relates to vacuolar dynamics and execution of cell death: in vivo imaging of hypersensitive cell death in tobacco BY-2 cells. Plant Cell Physiol 2007; 48:1414-25. [PMID: 17704529 DOI: 10.1093/pcp/pcm109] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Disintegration of the vacuolar membrane (VM) has been proposed to be a crucial event in various types of programmed cell death (PCD) in plants. However, its regulatory mechanisms are mostly unknown. To obtain new insights on the regulation of VM disintegration during hypersensitive cell death, we investigated the structural dynamics and permeability of the VM, as well as cytoskeletal reorganization during PCD in tobacco BY-2 cells induced by a proteinaceous elicitor, cryptogein. From sequential observations, we have identified the following remarkable events during PCD. Stage 1: bulb-like VM structures appear within the vacuolar lumen and the cortical microtubules are disrupted, while the cortical actin microfilaments are bundled. Simultaneously, transvacuolar strands including endoplasmic microtubules and actin microfilaments are gradually disrupted and the nucleus moves from the center to the periphery of the cell. Stage 2: cortical actin microfilament bundles and complex bulb-like VM structures disappear. The structure of the large central vacuole becomes simpler, and small spherical vacuoles appear. Stage 3: the VM is disintegrated and a fluorescent dye, BCECF, leaks out of the vacuoles just prior to PCD. Application of an actin polymerization inhibitor facilitates both the disappearance of bulb-like vacuolar membrane structures and induction of cell death. These results suggest that the elicitor-induced reorganization of actin microfilaments is involved in the regulation of hypersensitive cell death via modification of the vacuolar structure to induce VM disintegration.
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Affiliation(s)
- Takumi Higaki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha Kashiwa, Chiba, 277-8562 Japan
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41
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Tarragó-Trani MT, Storrie B. Alternate routes for drug delivery to the cell interior: pathways to the Golgi apparatus and endoplasmic reticulum. Adv Drug Deliv Rev 2007; 59:782-97. [PMID: 17669543 PMCID: PMC2134838 DOI: 10.1016/j.addr.2007.06.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Accepted: 06/12/2007] [Indexed: 11/29/2022]
Abstract
The targeted delivery of drugs to the cell interior can be accomplished by taking advantage of the various receptor-mediated endocytic pathways operating in a particular cell. Among these pathways, the retrograde trafficking pathway from endosomes to the Golgi apparatus, and endoplasmic reticulum is of special importance since it provides a route to deliver drugs bypassing the acid pH, hydrolytic environment of the lysosome. The existence of pathways for drug or antigen delivery to the endoplasmic reticulum and Golgi apparatus has been to a large extent an outcome of research on the trafficking of A/B type-bacterial or plant toxins such as Shiga toxin within the cell. The targeting properties of these toxins reside in their B subunit. In this article we present an overview of the multiplicity of pathways to deliver drugs intracellularly. We highlight the retrograde trafficking pathway illustrated by Shiga toxin and Shiga-like toxin, and the potential role of the B subunit of these toxins as carriers of drugs, antigens and imaging agents.
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Affiliation(s)
- Maria Teresa Tarragó-Trani
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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42
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Gazaryan IG, Krasinskaya IP, Kristal BS, Brown AM. Zinc irreversibly damages major enzymes of energy production and antioxidant defense prior to mitochondrial permeability transition. J Biol Chem 2007; 282:24373-80. [PMID: 17565998 DOI: 10.1074/jbc.m611376200] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent observations point to the role played by Zn2+ as an inducer of neuronal death. Two Zn2+ targets have been identified that result in inhibition of mitochondrial respiration: the bc1 center and, more recently, alpha-ketoglutarate dehydrogenase. Zn2+ is also a mediator of oxidative stress, leading to mitochondrial failure, release of apoptotic peptides, and neuronal death. We now present evidence, by means of direct biochemical assays, that Zn2+ is imported through the Ca2+ uniporter and directly targets major enzymes of energy production (lipoamide dehydrogenase) and antioxidant defense (thioredoxin reductase and glutathione reductase). We demonstrate the following. (a) These matrix enzymes are rapidly inhibited by application of Zn2+ to intact mitochondria. (b) Delayed treatment with membrane-impermeable chelators has no effect, indicating rapid transport of biologically relevant quantities of Zn2+ into the matrix. (c) Membrane-permeable chelators stop but do not reverse enzyme inactivation. (d) Enzyme inhibition is rapid and irreversible and precedes the major changes associated with the mitochondrial permeability transition (MPT). (e) The extent and rate of enzyme inactivation linearly correlates with the MPT onset and propagation. (f) The Ca2+ uniporter blocker, Ruthenium Red, protects enzyme activities and delays pore opening up to 2 microm Zn2+. An additional, unidentified import route functions at higher Zn2+ concentrations. (g) No enzyme inactivation is observed for Ca2+-induced MPT. These observations strongly suggest that, unlike Ca2+, exogenous Zn2+ interferes with mitochondrial NADH production and directly alters redox protection in the matrix, contributing to mitochondrial dysfunction. Inactivation of these enzymes by Zn2+ is irreversible, and thus only their de novo synthesis can restore function, which may underlie persistent loss of oxidative carbohydrate metabolism following transient ischemia.
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Affiliation(s)
- Irina G Gazaryan
- Burke Medical Research Institute, White Plains, New York 10605, USA
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43
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Aluri S, Büttner M. Identification and functional expression of the Arabidopsis thaliana vacuolar glucose transporter 1 and its role in seed germination and flowering. Proc Natl Acad Sci U S A 2007; 104:2537-42. [PMID: 17284600 PMCID: PMC1892959 DOI: 10.1073/pnas.0610278104] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Indexed: 11/18/2022] Open
Abstract
Sugar compartmentation into vacuoles of higher plants is a very important physiological process, providing extra space for transient and long-term sugar storage and contributing to the osmoregulation of cell turgor and shape. Despite the long-standing knowledge of this subcellular sugar partitioning, the proteins responsible for these transport steps have remained unknown. We have identified a gene family in Arabidopsis consisting of three members homologous to known sugar transporters. One member of this family, Arabidopsis thaliana vacuolar glucose transporter 1 (AtVGT1), was localized to the vacuolar membrane. Moreover, we provide evidence for transport activity of a tonoplast sugar transporter based on its functional expression in bakers' yeast and uptake studies in isolated yeast vacuoles. Analyses of Atvgt1 mutant lines indicate an important function of this vacuolar glucose transporter during developmental processes like seed germination and flowering.
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Affiliation(s)
- Sirisha Aluri
- Molekulare Pflanzenphysiologie, Universität Erlangen–Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
| | - Michael Büttner
- Molekulare Pflanzenphysiologie, Universität Erlangen–Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
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44
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Han P, McDonald HA, Bianchi BR, Kouhen RE, Vos MH, Jarvis MF, Faltynek CR, Moreland RB. Capsaicin causes protein synthesis inhibition and microtubule disassembly through TRPV1 activities both on the plasma membrane and intracellular membranes. Biochem Pharmacol 2007; 73:1635-45. [PMID: 17274957 DOI: 10.1016/j.bcp.2006.12.035] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 12/21/2006] [Accepted: 12/22/2006] [Indexed: 11/23/2022]
Abstract
TRPV1 is a non-selective cationic channel that is activated by capsaicin, acidic pH and thermal stimuli. Sustained TRPV1 channel activation causes severe cytotoxicity that leads to cell death. In this study, we investigated the mechanisms of capsaicin-induced cytotoxicity in HEK293 cells stably expressing TRPV1 with a focus on protein synthesis regulation and cytoskeleton reorganization. Capsaicin inhibited protein synthesis in TRPV1-expressing HEK cells with an IC(50) of 15.6nM and depolymerized microtubules within 10min after exposure. These effects were completely blocked by pretreatment of cells with the TRPV1 antagonist A-425619, both in the presence and absence of extracellular calcium. Protein synthesis inhibition induced by capsaicin was not a result of eIF2alpha hyperphosphorylation, but rather closely correlated with cytosolic calcium elevation caused by calcium flux through cell surface and intracellular TRPV1, and/or ER calcium depletion through intracellular TRPV1. Microtubule dependent cell process shrinkage may serve as a mechanism for rapid alteration of the neurotransmission network upon TRPV1 activation. Taken together, the present studies demonstrate that intracellular pool of TRPV1 plays an important role in regulating cell morphology and viability upon receptor activation.
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Affiliation(s)
- Ping Han
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064, USA.
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45
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Shirokova AV. [Apoptosis. Signaling network and changes of cell ion and water balance]. Tsitologiia 2007; 49:385-94. [PMID: 17654826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The review focuses on the shift of the monovalent ion balance, pH, and the membrane potential during apoptosis with respect to the ionic mechanism of apoptotic cell shrinkage. As an introduction the current views on the main signaling network, involved in the induction of apoptosis, i. e. receptor and mitochondrial pathways of caspase cascade activation and a caspase-independent induction of apoptosis are considered. The review summarizes the recent data on alteration of ion transporters and channels of the plasma membrane during apoptosis.
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46
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Pawlikowska P, Orzechowski A. [Role of transmembrane GTPases in mitochondrial morphology and activity]. Postepy Biochem 2007; 53:53-9. [PMID: 17718388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Mitochondria play crucial role in the energetic metabolism, thermogenesis, maintenance of calcium homeostasis and apoptosis. Cyclic changes in fusion and fission of mitochondria are required for properly functioning organelles, especially in tissues with high dependence on energy supply such as skeletal muscles, heart, or neurons. The key role of mitochondrial fusion is observed in embryonic development and maintaining unchanged mtDNA pool under conditions of oxidative stress. There is a large number of data indicating that mitochondrial networks often accompany the resistance to apoptotic stimuli. In contrast to fusion--the mitochondrial fission precedes apoptosis. According to the newest knowledge precise interactions between a few proteins are required for mitochondrial fusion and division. Among them Drp1, Mfn1, Mfn2 and Opal are considered the most important. Recent reports shed some light on the physiological importance of proteins participating in mitochondrial membrane dynamics in energy production, apoptosis and cellular signaling. In this review the authors report on the recent knowledge concerning structural changes of mitochondria with a particular interest to transmembrane GTPases and their role in cellular physiology.
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Affiliation(s)
- Patrycja Pawlikowska
- Katedra Nauk Fizjologicznych, Wydział Medycyny Weterynaryjnej, Szkoła Główna Gospodarstwa Wiejskiego, Warszawa
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47
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Maier AG, Rug M, O'Neill MT, Beeson JG, Marti M, Reeder J, Cowman AF. Skeleton-binding protein 1 functions at the parasitophorous vacuole membrane to traffic PfEMP1 to the Plasmodium falciparum-infected erythrocyte surface. Blood 2006; 109:1289-97. [PMID: 17023587 PMCID: PMC1785152 DOI: 10.1182/blood-2006-08-043364] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A key feature of Plasmodium falciparum, the parasite causing the most severe form of malaria in humans, is its ability to export parasite molecules onto the surface of the erythrocyte. The major virulence factor and variant surface protein PfEMP1 (P falciparum erythrocyte membrane protein 1) acts as a ligand to adhere to endothelial receptors avoiding splenic clearance. Because the erythrocyte is devoid of protein transport machinery, the parasite provides infrastructure for trafficking across membranes it traverses. In this study, we show that the P falciparum skeleton-binding protein 1 (PfSBP1) is required for transport of PfEMP1 to the P falciparum-infected erythrocyte surface. We present evidence that PfSBP1 functions at the parasitophorous vacuole membrane to load PfEMP1 into Maurer clefts during formation of these structures. Furthermore, the major reactivity of antibodies from malaria-exposed multigravid women is directed toward PfEMP1 because this is abolished in the absence of PfSBP1.
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Affiliation(s)
- Alexander G. Maier
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; and
| | - Melanie Rug
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; and
| | - Matthew T. O'Neill
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; and
| | - James G. Beeson
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; and
| | - Matthias Marti
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; and
| | - John Reeder
- Papua New Guinea Institute of Medical Research, Goroka, Papua, New Guinea
| | - Alan F. Cowman
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; and
- Correspondence: Alan F. Cowman, The Walter and Eliza Hall Institute of Medical Research, 1G, Royal Parade, Parkville, 3050, Melbourne, Australia; e-mail:
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48
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Cortázar TM, Hernández J, Echeverry MC, Camacho M. [Role of the parasitophorous vacuole of murine macrophages infected with Leishmania amazonensis in molecule acquisition]. Biomedica 2006; 26 Suppl 1:26-37. [PMID: 17361839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
INTRODUCTION Leishmania are intracellular parasites of macrophages, confined into compartments known as parasitophorous vacuoles. The permeability of this compartment depends on its interaction with the endocytic pathway and transport proteins present on its membrane. OBJECTIVE The membrane permeability of the parasitophorous vacuole was studied in J774.A1-macrophage like cells infected with Leishmania amazonensis, in situ and on isolated compartments. MATERIALS AND METHODS The parasitophorous vacuoles were isolated by density gradients. Fluorescent probe distribution and electrophysiological recordings were used to determine parasitophorous vacuole membrane permeability. Proton transport was evaluated indirectly by acridine orange staining. Probenecid sensitive ABC transporters were detected using the fluorescent probes lucifer yellow and calcein. For the first time ion currents were recorded on the membrane of isolated parasitophorous vacuoles using the patch clamp technique. RESULTS The parasitophorous vacuole stains red with acridine orange indicating an acidic compartment. It concentrates lucifer yellow by means of a probenecid sensitive transporter but excludes calcein. Isolated vacuoles stained red with acridine orange and concentrated lucifer yellow by means of a probenecid sensitive transporter. These vacuoles excluded calcein and showed an ion current in their membrane which is activated at potentials close to 60 mV with a mean conductance of 46 +/- 3 pS. CONCLUSIONS Isolated parasitophorous vacuoles with permeability properties preserving transport mechanisms similar to those found in situ can be purified. A poorly selective ion current on the parasitophorous vacuole membrane is reported for the first time.
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Affiliation(s)
- Tania M Cortázar
- Laboratorio de Biofísica, Centro Internacional de Física, Universidad Nacional de Colombia, Bogóta, D.C., Colombia
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49
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Abstract
Ca2+ entering a cell through a torn or disrupted plasma membrane rapidly triggers a combination of homotypic and exocytotic membrane fusion events. These events serve to erect a reparative membrane patch and then anneal it to the defect site. Annexin A1 is a cytosolic protein that, when activated by micromolar Ca2+, binds to membrane phospholipids, promoting membrane aggregation and fusion. We demonstrate here that an annexin A1 function-blocking antibody, a small peptide competitor, and a dominant-negative annexin A1 mutant protein incapable of Ca2+ binding all inhibit resealing. Moreover, we show that, coincident with a resealing event, annexin A1 becomes concentrated at disruption sites. We propose that Ca2+ entering through a disruption locally induces annexin A1 binding to membranes, initiating emergency fusion events whenever and wherever required.
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Affiliation(s)
- Anna K McNeil
- Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA
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50
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Vesteg M, Krajcovic J, Ebringer L. On the origin of eukaryotic cells and their endomembranes. Riv Biol 2006; 99:499-519. [PMID: 17299702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A novel hypothesis for the origin of eukaryotic cells is presented. It is assumed that the universal ancestor was bounded by two membranes of heterochiral lipid composition. We propose that the prokaryotic cells (the hypothetical host entity for alpha proteic-bacteria), though sharing a common ancestor with Archaea, was bounded by two membranes. The hypothesis suggests that an alpha proteic-bacterial symbiont was enclosed in the prokaryotic cells intermembrane space. In this view, the eukaryotic nuclear membrane and endomembrane system arose from the prokaryotic cells inner membrane while the eukaryotic plasma membrane arose from the prokaryotic cells outer membrane. The outlined scenario agrees with the view that engulfment of an alpha-proteic-bacterial cell by a host entity and its transformation to a mitochondrion was the driving force leading to the appearance of the first eukaryotic cell. The hypothesis seems to be consistent with the pre-cell theory, theory of membrane heredity, and the phagocytosis-late scenario.
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Affiliation(s)
- Matej Vesteg
- Institute of Cell Biology, Faculty of Natural Sciences, Comenius University, Mlynska dolina, 842 15 Bratislava, Slovakia.
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