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Liu Y, Hou D, Chen W, Lu X, Komaniecki GP, Xu Y, Yu T, Zhang SM, Linder ME, Lin H. MAVS Cys508 palmitoylation promotes its aggregation on the mitochondrial outer membrane and antiviral innate immunity. Proc Natl Acad Sci U S A 2024; 121:e2403392121. [PMID: 39141356 PMCID: PMC11348129 DOI: 10.1073/pnas.2403392121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 07/08/2024] [Indexed: 08/15/2024] Open
Abstract
Cysteine palmitoylation or S-palmitoylation catalyzed by the ZDHHC family of acyltransferases regulates the biological function of numerous mammalian proteins as well as viral proteins. However, understanding of the role of S-palmitoylation in antiviral immunity against RNA viruses remains very limited. The adaptor protein MAVS forms functionally essential prion-like aggregates upon activation by viral RNA-sensing RIG-I-like receptors. Here, we identify that MAVS, a C-terminal tail-anchored mitochondrial outer membrane protein, is S-palmitoylated by ZDHHC7 at Cys508, a residue adjacent to the tail-anchor transmembrane helix. Using superresolution microscopy and other biochemical techniques, we found that the mitochondrial localization of MAVS at resting state mainly depends on its transmembrane tail-anchor, without regulation by Cys508 S-palmitoylation. However, upon viral infection, MAVS S-palmitoylation stabilizes its aggregation on the mitochondrial outer membrane and thus promotes subsequent propagation of antiviral signaling. We further show that inhibition of MAVS S-palmitoylation increases the host susceptibility to RNA virus infection, highlighting the importance of S-palmitoylation in the antiviral innate immunity. Also, our results indicate ZDHHC7 as a potential therapeutic target for MAVS-related autoimmune diseases.
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Affiliation(s)
- Yinong Liu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY14853
| | - Dan Hou
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY14853
| | - Wenzhe Chen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY14853
| | - Xuan Lu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY14853
| | | | - Yilai Xu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY14853
| | - Tao Yu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY14853
| | - Sophia M. Zhang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY14853
| | - Maurine E. Linder
- Department of Molecular Medicine, Cornell University, Ithaca, NY14853
| | - Hening Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY14853
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
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2
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Iida N, Kawahara M, Hirota R, Shibagaki Y, Hattori S, Morikawa Y. A Proteomic Analysis of Detergent-Resistant Membranes in HIV Virological Synapse: The Involvement of Vimentin in CD4 Polarization. Viruses 2023; 15:1266. [PMID: 37376566 DOI: 10.3390/v15061266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
The cell-cell contact between HIV-1-infected and uninfected cells forms a virological synapse (VS) to allow for efficient HIV-1 transmission. Not only are HIV-1 components polarized and accumulate at cell-cell interfaces, but viral receptors and lipid raft markers are also. To better understand the nature of the HIV-1 VS, detergent-resistant membrane (DRM) fractions were isolated from an infected-uninfected cell coculture and compared to those from non-coculture samples using 2D fluorescence difference gel electrophoresis. Mass spectrometry revealed that ATP-related enzymes (ATP synthase subunit and vacuolar-type proton ATPase), protein translation factors (eukaryotic initiation factor 4A and mitochondrial elongation factor Tu), protein quality-control-related factors (protein disulfide isomerase A3 and 26S protease regulatory subunit), charged multivesicular body protein 4B, and vimentin were recruited to the VS. Membrane flotation centrifugation of the DRM fractions and confocal microscopy confirmed these findings. We further explored how vimentin contributes to the HIV-1 VS and found that vimentin supports HIV-1 transmission through the recruitment of CD4 to the cell-cell interface. Since many of the molecules identified in this study have previously been suggested to be involved in HIV-1 infection, we suggest that a 2D difference gel analysis of DRM-associated proteins may reveal the molecules that play crucial roles in HIV-1 cell-cell transmission.
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Affiliation(s)
- Naoyuki Iida
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Madoka Kawahara
- Omura Satoshi Memorial Institute and Graduate School for Infection Control, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Riku Hirota
- Omura Satoshi Memorial Institute and Graduate School for Infection Control, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Yoshio Shibagaki
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Seisuke Hattori
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Yuko Morikawa
- Omura Satoshi Memorial Institute and Graduate School for Infection Control, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
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3
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Oleynikov IP, Sudakov RV, Radyukhin VA, Arutyunyan AM, Azarkina NV, Vygodina TV. Interaction of Amphipathic Peptide from Influenza Virus M1 Protein with Mitochondrial Cytochrome Oxidase. Int J Mol Sci 2023; 24:ijms24044119. [PMID: 36835528 PMCID: PMC9961948 DOI: 10.3390/ijms24044119] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/07/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
The Bile Acid Binding Site (BABS) of cytochrome oxidase (CcO) binds numerous amphipathic ligands. To determine which of the BABS-lining residues are critical for interaction, we used the peptide P4 and its derivatives A1-A4. P4 is composed of two flexibly bound modified α-helices from the M1 protein of the influenza virus, each containing a cholesterol-recognizing CRAC motif. The effect of the peptides on the activity of CcO was studied in solution and in membranes. The secondary structure of the peptides was examined by molecular dynamics, circular dichroism spectroscopy, and testing the ability to form membrane pores. P4 was found to suppress the oxidase but not the peroxidase activity of solubilized CcO. The Ki(app) is linearly dependent on the dodecyl-maltoside (DM) concentration, indicating that DM and P4 compete in a 1:1 ratio. The true Ki is 3 μM. The deoxycholate-induced increase in Ki(app) points to a competition between P4 and deoxycholate. A1 and A4 inhibit solubilized CcO with Ki(app)~20 μM at 1 mM DM. A2 and A3 hardly inhibit CcO either in solution or in membranes. The mitochondrial membrane-bound CcO retains sensitivity to P4 and A4 but acquires resistance to A1. We associate the inhibitory effect of P4 with its binding to BABS and dysfunction of the proton channel K. Trp residue is critical for inhibition. The resistance of the membrane-bound enzyme to inhibition may be due to the disordered secondary structure of the inhibitory peptide.
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4
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Mollinedo F, Gajate C. Mitochondrial Targeting Involving Cholesterol-Rich Lipid Rafts in the Mechanism of Action of the Antitumor Ether Lipid and Alkylphospholipid Analog Edelfosine. Pharmaceutics 2021; 13:763. [PMID: 34065546 PMCID: PMC8161315 DOI: 10.3390/pharmaceutics13050763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 12/25/2022] Open
Abstract
The ether lipid edelfosine induces apoptosis selectively in tumor cells and is the prototypic molecule of a family of synthetic antitumor compounds collectively known as alkylphospholipid analogs. Cumulative evidence shows that edelfosine interacts with cholesterol-rich lipid rafts, endoplasmic reticulum (ER) and mitochondria. Edelfosine induces apoptosis in a number of hematological cancer cells by recruiting death receptors and downstream apoptotic signaling into lipid rafts, whereas it promotes apoptosis in solid tumor cells through an ER stress response. Edelfosine-induced apoptosis, mediated by lipid rafts and/or ER, requires the involvement of a mitochondrial-dependent step to eventually elicit cell death, leading to the loss of mitochondrial membrane potential, cytochrome c release and the triggering of cell death. The overexpression of Bcl-2 or Bcl-xL blocks edelfosine-induced apoptosis. Edelfosine induces the redistribution of lipid rafts from the plasma membrane to the mitochondria. The pro-apoptotic action of edelfosine on cancer cells is associated with the recruitment of F1FO-ATP synthase into cholesterol-rich lipid rafts. Specific inhibition of the FO sector of the F1FO-ATP synthase, which contains the membrane-embedded c-subunit ring that constitutes the mitochondrial permeability transcription pore, hinders edelfosine-induced cell death. Taking together, the evidence shown here suggests that the ether lipid edelfosine could modulate cell death in cancer cells by direct interaction with mitochondria, and the reorganization of raft-located mitochondrial proteins that critically modulate cell death or survival. Here, we summarize and discuss the involvement of mitochondria in the antitumor action of the ether lipid edelfosine, pointing out the mitochondrial targeting of this drug as a major therapeutic approach, which can be extrapolated to other alkylphospholipid analogs. We also discuss the involvement of cholesterol transport and cholesterol-rich lipid rafts in the interactions between the organelles as well as in the role of mitochondria in the regulation of apoptosis in cancer cells and cancer therapy.
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Affiliation(s)
- Faustino Mollinedo
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Laboratory of Cell Death and Cancer Therapy, Department of Molecular Biomedicine, C/Ramiro de Maeztu 9, E-28040 Madrid, Spain;
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5
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Yurinskaya MM, Garbuz DG, Afanasiev VN, Evgen’ev MB, Vinokurov MG. Effects of the Hydrogen Sulfide Donor GYY4137 and HSP70 Protein on the Activation of SH-SY5Y Cells by Lipopolysaccharide. Mol Biol 2021. [DOI: 10.1134/s002689332006014x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Kinnun JJ, Bolmatov D, Lavrentovich MO, Katsaras J. Lateral heterogeneity and domain formation in cellular membranes. Chem Phys Lipids 2020; 232:104976. [PMID: 32946808 PMCID: PMC7491465 DOI: 10.1016/j.chemphyslip.2020.104976] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/11/2020] [Accepted: 09/12/2020] [Indexed: 12/17/2022]
Abstract
As early as the development of the fluid mosaic model for cellular membranes, researchers began observing the telltale signs of lateral heterogeneity. Over the decades this has led to the development of the lipid raft hypothesis and the ensuing controversy that has unfolded, as a result. Here, we review the physical concepts behind domain formation in lipid membranes, both of their structural and dynamic origins. This, then leads into a discussion of coarse-grained, phenomenological approaches that describe the wide range of phases associated with lipid lateral heterogeneity. We use these physical concepts to describe the interaction between raft-lipid species, such as long-chain saturated lipids, sphingomyelin, and cholesterol, and non-raft forming lipids, such as those with short acyl chains or unsaturated fatty acids. While debate has persisted on the biological relevance of lipid domains, recent research, described here, continues to identify biological roles for rafts and new experimental approaches have revealed the existence of lipid domains in living systems. Given the recent progress on both the biological and structural aspects of raft formation, the research area of membrane lateral heterogeneity will not only expand, but will continue to produce exciting results.
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Affiliation(s)
- Jacob J Kinnun
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States; Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
| | - Dima Bolmatov
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States; Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States.
| | - Maxim O Lavrentovich
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States.
| | - John Katsaras
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States; Sample Environment Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
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7
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Ouweneel AB, Thomas MJ, Sorci-Thomas MG. The ins and outs of lipid rafts: functions in intracellular cholesterol homeostasis, microparticles, and cell membranes: Thematic Review Series: Biology of Lipid Rafts. J Lipid Res 2020; 61:676-686. [PMID: 33715815 PMCID: PMC7193959 DOI: 10.1194/jlr.tr119000383] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/17/2019] [Indexed: 12/12/2022] Open
Abstract
Cellular membranes are not homogenous mixtures of proteins; rather, they are segregated into microdomains on the basis of preferential association between specific lipids and proteins. These microdomains, called lipid rafts, are well known for their role in receptor signaling on the plasma membrane (PM) and are essential to such cellular functions as signal transduction and spatial organization of the PM. A number of disease states, including atherosclerosis and other cardiovascular disorders, may be caused by dysfunctional maintenance of lipid rafts. Lipid rafts do not occur only in the PM but also have been found in intracellular membranes and extracellular vesicles (EVs). Here, we focus on discussing newly discovered functions of lipid rafts and microdomains in intracellular membranes, including lipid and protein trafficking from the ER, Golgi bodies, and endosomes to the PM, and we examine lipid raft involvement in the production and composition of EVs. Because lipid rafts are small and transient, visualization remains challenging. Future work with advanced techniques will continue to expand our knowledge about the roles of lipid rafts in cellular functioning.
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Affiliation(s)
- Amber B Ouweneel
- Department of Medicine, Division of Endocrinology and Molecular Medicine,Medical College of Wisconsin, Milwaukee, WI 53226; Cardiovascular Center,Medical College of Wisconsin, Milwaukee, WI 53226
| | - Michael J Thomas
- Cardiovascular Center,Medical College of Wisconsin, Milwaukee, WI 53226; Department of Pharmacology and Toxicology,Medical College of Wisconsin, Milwaukee, WI 53226
| | - Mary G Sorci-Thomas
- Department of Medicine, Division of Endocrinology and Molecular Medicine,Medical College of Wisconsin, Milwaukee, WI 53226; Cardiovascular Center,Medical College of Wisconsin, Milwaukee, WI 53226; Department of Pharmacology and Toxicology,Medical College of Wisconsin, Milwaukee, WI 53226. mailto:
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8
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Desai R, Campanella M. Exploring mitochondrial cholesterol signalling for therapeutic intervention in neurological conditions. Br J Pharmacol 2019; 176:4284-4292. [PMID: 31077345 PMCID: PMC6887905 DOI: 10.1111/bph.14697] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 02/25/2019] [Accepted: 03/10/2019] [Indexed: 02/06/2023] Open
Abstract
The pharmacological targeting of cholesterol levels continues to generate interest due to the undoubted success of therapeutic agents, such as statins, in extending life expectancy by modifying the prognosis of diseases associated with the impairment of lipid metabolism. Advances in our understanding of mitochondrial dysfunction in chronic age-related diseases of the brain have disclosed an emerging role for mitochondrial cholesterol in their pathophysiology, thus delineating an opportunity to provide mechanistic insights and explore strategies of intervention. This review draws attention to novel signalling mechanisms in conditions linked with impaired metabolism associated with impaired handling of cholesterol and its oxidized forms (oxysterols) by mitochondria. By emphasizing the role of mitochondrial cholesterol in neurological diseases, we here call for novel approaches and new means of assessment. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.
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Affiliation(s)
- Radha Desai
- Department of Comparative Biomedical SciencesThe Royal Veterinary College, University of LondonLondonUK
| | - Michelangelo Campanella
- Department of Comparative Biomedical SciencesThe Royal Veterinary College, University of LondonLondonUK
- Consortium for Mitochondrial Research (CfMR)University College LondonLondonUK
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9
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Proteomic Analysis of Lipid Rafts from RBL-2H3 Mast Cells. Int J Mol Sci 2019; 20:ijms20163904. [PMID: 31405203 PMCID: PMC6720779 DOI: 10.3390/ijms20163904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/01/2019] [Accepted: 08/08/2019] [Indexed: 12/15/2022] Open
Abstract
Lipid rafts are highly ordered membrane microdomains enriched in cholesterol, glycosphingolipids, and certain proteins. They are involved in the regulation of cellular processes in diverse cell types, including mast cells (MCs). The MC lipid raft protein composition was assessed using qualitative mass spectrometric characterization of the proteome from detergent-resistant membrane fractions from RBL-2H3 MCs. Using two different post-isolation treatment methods, a total of 949 lipid raft associated proteins were identified. The majority of these MC lipid raft proteins had already been described in the RaftProtV2 database and are among highest cited/experimentally validated lipid raft proteins. Additionally, more than half of the identified proteins had lipid modifications and/or transmembrane domains. Classification of identified proteins into functional categories showed that the proteins were associated with cellular membrane compartments, and with some biological and molecular functions, such as regulation, localization, binding, catalytic activity, and response to stimulus. Furthermore, functional enrichment analysis demonstrated an intimate involvement of identified proteins with various aspects of MC biological processes, especially those related to regulated secretion, organization/stabilization of macromolecules complexes, and signal transduction. This study represents the first comprehensive proteomic profile of MC lipid rafts and provides additional information to elucidate immunoregulatory functions coordinated by raft proteins in MCs.
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10
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Ouyang M, Wan R, Qin Q, Peng Q, Wang P, Wu J, Allen M, Shi Y, Laub S, Deng L, Lu S, Wang Y. Sensitive FRET Biosensor Reveals Fyn Kinase Regulation by Submembrane Localization. ACS Sens 2019; 4:76-86. [PMID: 30588803 DOI: 10.1021/acssensors.8b00896] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fyn kinase plays crucial roles in hematology and T cell signaling; however, there are currently limited tools to visualize the dynamic Fyn activity in live cells. Here we developed and characterized a highly sensitive Fyn biosensor based on fluorescence resonance energy transfer (FRET) to monitor Fyn kinase activity in live cells. Our results show that Fyn kinase activity can be induced in both mouse embryonic fibroblasts (MEFs) and T cells by ligand engagement. Two different motifs were further introduced to target the biosensor at the cellular membrane microdomains in MEFs, revealing that the Fyn-tagged biosensor had 70% greater response to growth factor stimulation than the Lyn-tagged version. This suggests that the plasma membrane microdomains can be categorized into different functional subdomains. Further experiments show that while the membrane accessibility is necessary for Fyn activation, the localization of Fyn outside of its microdomains causes its hyperactivity, indicating that membrane microdomains provide a suppressive microenvironment for Fyn regulation in MEFs. Interestingly, a relatively high Fyn activity can be observed at perinuclear regions, further supporting the notion that the membrane microenvironment has a significant impact on the local molecular functions. Our work hence highlights a novel Fyn FRET biosensor for live cell imaging and its application in revealing an intricate submembrane regulation of Fyn in live MEFs.
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Affiliation(s)
- Mingxing Ouyang
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu Province 213164, China
| | - Rongxue Wan
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
| | - Qin Qin
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Qin Peng
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Pengzhi Wang
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Jenny Wu
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Molly Allen
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Yiwen Shi
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Shannon Laub
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Linhong Deng
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu Province 213164, China
| | - Shaoying Lu
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Yingxiao Wang
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
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11
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Kang SJ, Kim JS, Park SM. Ubiquitin C-terminal Hydrolase L1 Regulates Lipid Raft-dependent Endocytosis. Exp Neurobiol 2018; 27:377-386. [PMID: 30429647 PMCID: PMC6221840 DOI: 10.5607/en.2018.27.5.377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 11/19/2022] Open
Abstract
Ubiquitin C-terminal hydrolase L1 (UCH-L1) is a deubiquitinating enzyme that is highly expressed in neurons, and gathering evidence indicates that UCH-L1 may play pathogenic roles in many neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease (PD). Additionally, lipid rafts have attracted interest in neurodegeneration as playing a common role in many neurodegenerative diseases. In the present study, we demonstrated that UCH-L1 associates with lipid rafts as with other PD-associated gene products. In addition, UCH-L1 regulates lipid raft-dependent endocytosis and it is not dependent on the expression and degradation of caveolin-1 or flotillin-1. Finally, UCH-L1 regulates cell-to-cell transmission of α-synuclein. This study provides evidence that many PD-associated gene products share common signaling pathways to explain the pathogenesis of PD.
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Affiliation(s)
- Seo-Jun Kang
- Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Korea.,BK21 plus program, Department of Biological Sciences, Ajou University School of Medicine, Suwon 16499, Korea
| | - Jin Soo Kim
- Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Korea
| | - Sang Myun Park
- Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Korea.,BK21 plus program, Department of Biological Sciences, Ajou University School of Medicine, Suwon 16499, Korea
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12
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Sullivan EM, Pennington ER, Green WD, Beck MA, Brown DA, Shaikh SR. Mechanisms by Which Dietary Fatty Acids Regulate Mitochondrial Structure-Function in Health and Disease. Adv Nutr 2018; 9:247-262. [PMID: 29767698 PMCID: PMC5952932 DOI: 10.1093/advances/nmy007] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/02/2018] [Accepted: 01/30/2018] [Indexed: 02/06/2023] Open
Abstract
Mitochondria are the energy-producing organelles within a cell. Furthermore, mitochondria have a role in maintaining cellular homeostasis and proper calcium concentrations, building critical components of hormones and other signaling molecules, and controlling apoptosis. Structurally, mitochondria are unique because they have 2 membranes that allow for compartmentalization. The composition and molecular organization of these membranes are crucial to the maintenance and function of mitochondria. In this review, we first present a general overview of mitochondrial membrane biochemistry and biophysics followed by the role of different dietary saturated and unsaturated fatty acids in modulating mitochondrial membrane structure-function. We focus extensively on long-chain n-3 (ω-3) polyunsaturated fatty acids and their underlying mechanisms of action. Finally, we discuss implications of understanding molecular mechanisms by which dietary n-3 fatty acids target mitochondrial structure-function in metabolic diseases such as obesity, cardiac-ischemia reperfusion injury, obesity, type 2 diabetes, nonalcoholic fatty liver disease, and select cancers.
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Affiliation(s)
- E Madison Sullivan
- Department of Biochemistry and Molecular Biology and
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, NC
| | - Edward Ross Pennington
- Department of Biochemistry and Molecular Biology and
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, NC
- Department of Nutrition, The University of North Carolina at Chapel Hill, Gillings School of Global Public Health and School of Medicine, Chapel Hill, NC
| | - William D Green
- Department of Nutrition, The University of North Carolina at Chapel Hill, Gillings School of Global Public Health and School of Medicine, Chapel Hill, NC
| | - Melinda A Beck
- Department of Nutrition, The University of North Carolina at Chapel Hill, Gillings School of Global Public Health and School of Medicine, Chapel Hill, NC
| | - David A Brown
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech Corporate Research Center, Blacksburg, VA
| | - Saame Raza Shaikh
- Department of Nutrition, The University of North Carolina at Chapel Hill, Gillings School of Global Public Health and School of Medicine, Chapel Hill, NC
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13
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A key role for MAM in mediating mitochondrial dysfunction in Alzheimer disease. Cell Death Dis 2018; 9:335. [PMID: 29491396 PMCID: PMC5832428 DOI: 10.1038/s41419-017-0215-0] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/27/2017] [Accepted: 12/06/2017] [Indexed: 12/19/2022]
Abstract
In the last few years, increased emphasis has been devoted to understanding the contribution of mitochondria-associated endoplasmic reticulum (ER) membranes (MAM) to human pathology in general, and neurodegenerative diseases in particular. A major reason for this is the central role that this subdomain of the ER plays in metabolic regulation and in mitochondrial biology. As such, aberrant MAM function may help explain the seemingly unrelated metabolic abnormalities often seen in neurodegeneration. In the specific case of Alzheimer disease (AD), besides perturbations in calcium and lipid homeostasis, there are numerous documented alterations in mitochondrial behavior and function, including reduced respiratory chain activity and oxidative phosphorylation, increased free radical production, and altered organellar morphology, dynamics, and positioning (especially perinuclear mitochondria). However, whether these alterations are primary events causative of the disease, or are secondary downstream events that are the result of some other, more fundamental problem, is still unclear. In support of the former possibility, we recently reported that C99, the C-terminal processing product of the amyloid precursor protein (APP) derived from its cleavage by β-secretase, is present in MAM, that its level is increased in AD, and that this increase reduces mitochondrial respiration, likely via a C99-induced alteration in cellular sphingolipid homeostasis. Thus, the metabolic disturbances seen in AD likely arise from increased ER-mitochondrial communication that is driven by an increase in the levels of C99 at the MAM.
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14
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Zheng YZ, DeMarco ML. Manipulating trypsin digestion conditions to accelerate proteolysis and simplify digestion workflows in development of protein mass spectrometric assays for the clinical laboratory. CLINICAL MASS SPECTROMETRY (DEL MAR, CALIF.) 2017; 6:1-12. [PMID: 39193414 PMCID: PMC11322774 DOI: 10.1016/j.clinms.2017.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 10/09/2017] [Accepted: 10/17/2017] [Indexed: 01/15/2023]
Abstract
For ease of measurement and accurate identification of proteins by mass spectrometry, protein targets are commonly cleaved into peptides. Protein digestion is a critical step in sample preparation, yielding peptides amenable to both chromatographic separation and mass spectrometric analysis. Trypsin is the most extensively used protease due to its high cleavage specificity; however, it can yield highly variable digestion profiles and is dependent on several factors including digestion buffer, denaturant, trypsin quality selected, and composition/complexity of the sample matrix. Historically, trypsin digestion protocols have relied on lengthy digestion times-which are unsuitable for many clinical applications-to ensure effective proteolysis. Here, we performed an iterative and comprehensive evaluation of digestion conditions for five structurally diverse proteins in plasma and serum: apolipoprotein A-1, retinol-binding protein 4, transthyretin, complement component 9 and C-reactive protein. Conditions were monitored for improvements in signal intensity, reproducibility of digestion profile, and rate of release of proteolytic peptides. This approach yielded an optimized digestion protocol for detection of all five proteins in a single workflow requiring a brief 20 min digestion, without the use of chemical denaturants or reduction/alkylation steps, and only 1 μl of plasma. It is our hope that this data can accelerate the development phase of targeted mass spectrometric protein assays by identifying practical approaches to accelerate and simplify digestion protocols for clinical applications and assist with the selection of tryptic peptides for protein quantitation.
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Affiliation(s)
- Yu Zi Zheng
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
| | - Mari L. DeMarco
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
- Department of Pathology and Laboratory Medicine, St. Paul’s Hospital, Providence Health Care, Vancouver, Canada
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15
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Ushiyama A, Tajima A, Ishikawa N, Asano A. Characterization of the functions and proteomes associated with membrane rafts in chicken sperm. PLoS One 2017; 12:e0186482. [PMID: 29095853 PMCID: PMC5667776 DOI: 10.1371/journal.pone.0186482] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/02/2017] [Indexed: 01/23/2023] Open
Abstract
Cellular membranes are heterogeneous, and this has a great impact on cellular function. Despite the central role of membrane functions in multiple cellular processes in sperm, their molecular mechanisms are poorly understood. Membrane rafts are specific membrane domains enriched in cholesterol, ganglioside GM1, and functional proteins, and they are involved in the regulation of a variety of cellular functions. Studies of the functional characterization of membrane rafts in mammalian sperm have demonstrated roles in sperm-egg binding and the acrosomal reaction. Recently, our biochemical and cell biological studies showed that membrane rafts are present and might play functional roles in chicken sperm. In this study, we isolated membrane rafts from chicken sperm as a detergent-resistant membranes (DRM) floating on a density gradient in the presence of 1% Triton X-100, and characterized the function and proteomes associated with these domains. Biochemical comparison of the DRM between fresh and cryopreserved sperm demonstrated that cryopreservation induces cholesterol loss specifically from membrane rafts, indicating the functional connection with reduced post-thaw fertility in chicken sperm. Furthermore, using an avidin-biotin system, we found that sperm DRM is highly enriched in a 60 KDa single protein able to bind to the inner perivitelline layer. To identify possible roles of membrane rafts, quantitative proteomics, combined with a stable isotope dimethyl labeling approach, identified 82 proteins exclusively or relatively more associated with membrane rafts. Our results demonstrate the functional distinctions between membrane domains and provide compelling evidence that membrane rafts are involved in various cellular pathways inherent to chicken sperm.
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Affiliation(s)
- Ai Ushiyama
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Atsushi Tajima
- Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Naoto Ishikawa
- Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Atsushi Asano
- Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
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16
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Herrera-Cruz MS, Simmen T. Of yeast, mice and men: MAMs come in two flavors. Biol Direct 2017; 12:3. [PMID: 28122638 PMCID: PMC5267431 DOI: 10.1186/s13062-017-0174-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/18/2017] [Indexed: 12/15/2022] Open
Abstract
The past decade has seen dramatic progress in our understanding of membrane contact sites (MCS). Important examples of these are endoplasmic reticulum (ER)-mitochondria contact sites. ER-mitochondria contacts have originally been discovered in mammalian tissue, where they have been designated as mitochondria-associated membranes (MAMs). It is also in this model system, where the first critical MAM proteins have been identified, including MAM tethering regulators such as phospho-furin acidic cluster sorting protein 2 (PACS-2) and mitofusin-2. However, the past decade has seen the discovery of the MAM also in the powerful yeast model system Saccharomyces cerevisiae. This has led to the discovery of novel MAM tethers such as the yeast ER-mitochondria encounter structure (ERMES), absent in the mammalian system, but whose regulators Gem1 and Lam6 are conserved. While MAMs, sometimes referred to as mitochondria-ER contacts (MERCs), regulate lipid metabolism, Ca2+ signaling, bioenergetics, inflammation, autophagy and apoptosis, not all of these functions exist in both systems or operate differently. This biological difference has led to puzzling discrepancies on findings obtained in yeast or mammalian cells at the moment. Our review aims to shed some light onto mechanistic differences between yeast and mammalian MAM and their underlying causes. Reviewers: This article was reviewed by Paola Pizzo (nominated by Luca Pellegrini), Maya Schuldiner and György Szabadkai (nominated by Luca Pellegrini).
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Affiliation(s)
- Maria Sol Herrera-Cruz
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G2H7, Canada
| | - Thomas Simmen
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G2H7, Canada.
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17
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Pennington ER, Fix A, Sullivan EM, Brown DA, Kennedy A, Shaikh SR. Distinct membrane properties are differentially influenced by cardiolipin content and acyl chain composition in biomimetic membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:257-267. [PMID: 27889304 DOI: 10.1016/j.bbamem.2016.11.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/21/2016] [Accepted: 11/22/2016] [Indexed: 12/14/2022]
Abstract
Cardiolipin (CL) has a critical role in maintaining mitochondrial inner membrane structure. In several conditions such as heart failure and aging, there is loss of CL content and remodeling of CL acyl chains, which are hypothesized to impair mitochondrial inner membrane biophysical organization. Therefore, this study discriminated how CL content and acyl chain composition influenced select properties of simple and complex mitochondrial mimicking model membranes. We focused on monolayer excess area/molecule (a measure of lipid miscibility), bilayer phase transitions, and microdomain organization. In monolayer compression studies, loss of tetralinoleoyl [(18:2)4] CL content decreased the excess area/molecule. Replacement of (18:2)4CL acyl chains with tetraoleoyl [(18:1)4] CL or tetradocosahexaenoyl [(22:6)4] CL generally had little influence on monolayer excess area/molecule; in contrast, replacement of (18:2)4CL acyl chains with tetramyristoyl [(14:0)4] CL increased monolayer excess area/molecule. In bilayers, calorimetric studies showed that substitution of (18:2)4CL with (18:1)4CL or (22:6)4CL lowered the phase transition temperature of phosphatidylcholine vesicles whereas (14:0)4CL had no effect. Finally, quantitative imaging of giant unilamellar vesicles revealed differential effects of CL content and acyl chain composition on microdomain organization, visualized with the fluorescent probe Texas Red DHPE. Notably, microdomain areas were decreased by differing magnitudes upon lowering of (18:2)4CL content and substitution of (18:2)4CL with (14:0)4CL or (22:6)4CL. Conversely, exchanging (18:2)4CL with (18:1)4CL increased microdomain area. Altogether, these data demonstrate that CL content and fatty acyl composition differentially target membrane physical properties, which has implications for understanding how CL regulates mitochondrial activity and the design of CL-specific therapeutics.
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Affiliation(s)
- Edward Ross Pennington
- Department of Biochemistry & Molecular Biology, USA; East Carolina Diabetes & Obesity Institute, Brody School of Medicine, East Carolina University, 115 Heart Drive, Mail Stop 743, Greenville, NC 27834, USA
| | - Amy Fix
- Department of Biochemistry & Molecular Biology, USA
| | - E Madison Sullivan
- Department of Biochemistry & Molecular Biology, USA; East Carolina Diabetes & Obesity Institute, Brody School of Medicine, East Carolina University, 115 Heart Drive, Mail Stop 743, Greenville, NC 27834, USA
| | - David A Brown
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech Corporate Research Center, 1035 ILSB, 1981 Kraft Drive, Blacksburg, VA 24060, USA
| | - Anthony Kennedy
- Department of Chemistry, East 10th Street, Mail Stop 552, East Carolina University, Greenville, NC 27854, USA
| | - Saame Raza Shaikh
- Department of Biochemistry & Molecular Biology, USA; East Carolina Diabetes & Obesity Institute, Brody School of Medicine, East Carolina University, 115 Heart Drive, Mail Stop 743, Greenville, NC 27834, USA.
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18
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Modulation of Mitochondrial Antiviral Signaling by Human Herpesvirus 8 Interferon Regulatory Factor 1. J Virol 2015; 90:506-20. [PMID: 26512076 DOI: 10.1128/jvi.01903-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 10/14/2015] [Indexed: 02/04/2023] Open
Abstract
UNLABELLED Mitochondrial lipid raft-like microdomains, experimentally also termed mitochondrial detergent-resistant membrane fractions (mDRM), play a role as platforms for recruiting signaling molecules involved in antiviral responses such as apoptosis and innate immunity. Viruses can modulate mitochondrial functions for their own survival and replication. However, viral regulation of the antiviral responses via mDRM remains incompletely understood. Here, we report that human herpesvirus 8 (HHV-8) gene product viral interferon regulatory factor 1 (vIRF-1) is targeted to mDRM during virus replication and negatively regulates the mitochondrial antiviral signaling protein (MAVS)-mediated antiviral responses. The N-terminal region of vIRF-1 interacts directly with membrane lipids, including cardiolipin. In addition, a GxRP motif within the N terminus of vIRF-1, conserved in the mDRM-targeting region of mitochondrial proteins, including PTEN-induced putative kinase 1 (PINK1) and MAVS, was found to be important for vIRF-1 association with mitochondria. Furthermore, MAVS, which has the potential to promote vIRF-1 targeting to mDRM possibly by inducing cardiolipin exposure on the outer membrane of mitochondria, interacts with vIRF-1, which, in turn, inhibits MAVS-mediated antiviral signaling. Consistent with these results, vIRF-1 targeting to mDRM contributes to promotion of HHV-8 productive replication and inhibition of associated apoptosis. Combined, our results suggest novel molecular mechanisms for negative-feedback regulation of MAVS by vIRF-1 during virus replication. IMPORTANCE Successful virus replication is in large part achieved by the ability of viruses to counteract apoptosis and innate immune responses elicited by infection of host cells. Recently, mitochondria have emerged to play a central role in antiviral signaling. In particular, mitochondrial lipid raft-like microdomains appear to function as platforms in cell apoptosis signaling. However, viral regulation of antiviral signaling through the mitochondrial microdomains remains incompletely understood. The present study demonstrates that HHV-8-encoded vIRF-1 targets to the mitochondrial detergent-resistant microdomains via direct interaction with cardiolipin and inhibits MAVS protein-mediated apoptosis and type I interferon gene expression in a negative-feedback manner, thus promoting HHV-8 productive replication. These results suggest that vIRF-1 is the first example of a viral protein to inhibit mitochondrial antiviral signaling through lipid raft-like microdomains.
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19
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Human Mitochondrial DNA-Protein Complexes Attach to a Cholesterol-Rich Membrane Structure. Sci Rep 2015; 5:15292. [PMID: 26478270 PMCID: PMC4609938 DOI: 10.1038/srep15292] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/22/2015] [Indexed: 01/05/2023] Open
Abstract
The helicase Twinkle is indispensable for mtDNA replication in nucleoids. Previously, we showed that Twinkle is tightly membrane-associated even in the absence of mtDNA, which suggests that Twinkle is part of a membrane-attached replication platform. Here we show that this platform is a cholesterol-rich membrane structure. We fractionated mitochondrial membrane preparations on flotation gradients and show that membrane-associated nucleoids accumulate at the top of the gradient. This fraction was shown to be highly enriched in cholesterol, a lipid that is otherwise low abundant in mitochondria. In contrast, more common mitochondrial lipids, and abundant inner-membrane associated proteins concentrated in the bottom-half of these gradients. Gene silencing of ATAD3, a protein with proposed functions related to nucleoid and mitochondrial cholesterol homeostasis, modified the distribution of cholesterol and nucleoids in the gradient in an identical fashion. Both cholesterol and ATAD3 were previously shown to be enriched in ER-mitochondrial junctions, and we detect nucleoid components in biochemical isolates of these structures. Our data suggest an uncommon membrane composition that accommodates platforms for replicating mtDNA, and reconcile apparently disparate functions of ATAD3. We suggest that mtDNA replication platforms are organized in connection with ER-mitochondrial junctions, facilitated by a specialized membrane architecture involving mitochondrial cholesterol.
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20
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Fiorini R, Pagliarani A, Nesci S, Trombetti F, Pirini M, Fabbri M, Ventrella V. Lipid unsaturation per se does not explain the physical state of mitochondrial membranes in Mytilus galloprovincialis. Comp Biochem Physiol B Biochem Mol Biol 2015; 191:66-75. [PMID: 26456349 DOI: 10.1016/j.cbpb.2015.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/24/2015] [Accepted: 09/25/2015] [Indexed: 01/28/2023]
Abstract
Through a multiple approach, the present study on the mitochondrial membranes from mussel gills and swine heart combines some biochemical information on fatty acid composition, sterol pattern, and temperature dependence of the F1FO-ATPase activity (EC 3.6.3.14.) with fluorescence data on mitochondrial membranes and on liposomes obtained from lipid extracts of mitochondria. The physical state of mussel gills and swine heart was investigated by Laurdan steady state fluorescence. Quite surprisingly, the similar temperature dependence of the F1FO complex, illustrated as Arrhenius plot which in both mitochondria exhibits the same discontinuity at approximately 21°C and overlapping activation energies above and below the discontinuity, is apparently compatible with a different composition and physical state of mitochondrial membranes. Accordingly, mussel membranes contain highly unsaturated fatty acids, abundant sterols, including phytosterols, while mammalian membranes only contain cholesterol and in prevalence shorter and less unsaturated fatty acids, leading to a lower membrane unsaturation with respect to mussel mitochondria. As suggested by fluorescence data, the likely formation of peculiar microdomains interacting with the membrane-bound enzyme complex in mussel mitochondria could produce an environment which somehow approaches the physical state of mammalian mitochondrial membranes. Thus, as an adaptive strategy, the interaction between sterols, highly unsaturated phospholipids and proteins in mussel gill mitochondria could allow the F1FO-ATPase activity to maintain the same activation energy as the mammalian enzyme.
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Affiliation(s)
- Rosamaria Fiorini
- Department of Life and Environmental Sciences, Marche Polytechnic University, Montedago, 60131 Ancona, Italy.
| | - Alessandra Pagliarani
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano Emilia, Bologna, Italy
| | - Salvatore Nesci
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano Emilia, Bologna, Italy
| | - Fabiana Trombetti
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano Emilia, Bologna, Italy
| | - Maurizio Pirini
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano Emilia, Bologna, Italy
| | - Micaela Fabbri
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano Emilia, Bologna, Italy
| | - Vittoria Ventrella
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano Emilia, Bologna, Italy
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21
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Autophagy of mitochondria: a promising therapeutic target for neurodegenerative disease. Cell Biochem Biophys 2015; 70:707-19. [PMID: 24807843 DOI: 10.1007/s12013-014-0006-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The autophagic process is the only known mechanism for mitochondrial turnover and it has been speculated that dysfunction of autophagy may result in mitochondrial error and cellular stress. Emerging investigations have provided new understanding of how autophagy of mitochondria (also known as mitophagy) is associated with cellular oxidative stress and its impact on neurodegeneration. This impaired autophagic function may be considered as a possible mechanism in the pathogenesis of several neurodegenerative disorders including Parkinson's disease, Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington disease. It can be suggested that autophagy dysfunction along with oxidative stress is considered main events in neurodegenerative disorders. New therapeutic approaches have now begun to target mitochondria as a potential drug target. This review discusses evidence supporting the notion that oxidative stress and autophagy are intimately associated with neurodegenerative disease pathogenesis. This review also explores new approaches that can prevent mitochondrial dysfunction, improve neurodegenerative etiology, and also offer possible cures to the aforementioned neurodegenerative diseases.
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22
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Guardia-Laguarta C, Area-Gomez E, Schon EA, Przedborski S. A new role for α-synuclein in Parkinson's disease: Alteration of ER-mitochondrial communication. Mov Disord 2015; 30:1026-33. [DOI: 10.1002/mds.26239] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 03/10/2015] [Accepted: 03/19/2015] [Indexed: 12/28/2022] Open
Affiliation(s)
| | - Estela Area-Gomez
- Department of Neurology; Columbia University Medical Center; New York NY USA
| | - Eric A. Schon
- Department of Neurology; Columbia University Medical Center; New York NY USA
- Department of Genetics and Development; Columbia University Medical Center; New York NY USA
| | - Serge Przedborski
- Department of Pathology and Cell Biology; Columbia University Medical Center; New York NY USA
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23
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Wypijewski KJ, Tinti M, Chen W, Lamont D, Ashford MLJ, Calaghan SC, Fuller W. Identification of caveolar resident proteins in ventricular myocytes using a quantitative proteomic approach: dynamic changes in caveolar composition following adrenoceptor activation. Mol Cell Proteomics 2015; 14:596-608. [PMID: 25561500 PMCID: PMC4349980 DOI: 10.1074/mcp.m114.038570] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The lipid raft concept proposes that membrane environments enriched in cholesterol and sphingolipids cluster certain proteins and form platforms to integrate cell signaling. In cardiac muscle, caveolae concentrate signaling molecules and ion transporters, and play a vital role in adrenergic regulation of excitation–contraction coupling, and consequently cardiac contractility. Proteomic analysis of cardiac caveolae is hampered by the presence of contaminants that have sometimes, erroneously, been proposed to be resident in these domains. Here we present the first unbiased analysis of the proteome of cardiac caveolae, and investigate dynamic changes in their protein constituents following adrenoreceptor (AR) stimulation. Rat ventricular myocytes were treated with methyl-β-cyclodextrin (MβCD) to deplete cholesterol and disrupt caveolae. Buoyant caveolin-enriched microdomains (BCEMs) were prepared from MβCD-treated and control cell lysates using a standard discontinuous sucrose gradient. BCEMs were harvested, pelleted, and resolubilized, then alkylated, digested, and labeled with iTRAQ reagents, and proteins identified by LC-MS/MS on a LTQ Orbitrap Velos Pro. Proteins were defined as BCEM resident if they were consistently depleted from the BCEM fraction following MβCD treatment. Selective activation of α-, β1-, and β2-AR prior to preparation of BCEMs was achieved by application of agonist/antagonist pairs for 10 min in populations of field-stimulated myocytes. We typically identified 600–850 proteins per experiment, of which, 249 were defined as high-confidence BCEM residents. Functional annotation clustering indicates cardiac BCEMs are enriched in integrin signaling, guanine nucleotide binding, ion transport, and insulin signaling clusters. Proteins possessing a caveolin binding motif were poorly enriched in BCEMs, suggesting this is not the only mechanism that targets proteins to caveolae. With the notable exception of the cavin family, very few proteins show altered abundance in BCEMs following AR activation, suggesting signaling complexes are preformed in BCEMs to ensure a rapid and high fidelity response to adrenergic stimulation in cardiac muscle.
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Affiliation(s)
- Krzysztof J Wypijewski
- From the ‡Division of Cardiovascular and Diabetes Medicine, College of Medicine, Dentistry and Nursing, University of Dundee, Dundee, United Kingdom
| | - Michele Tinti
- §College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Wenzhang Chen
- §College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Douglas Lamont
- §College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michael L J Ashford
- From the ‡Division of Cardiovascular and Diabetes Medicine, College of Medicine, Dentistry and Nursing, University of Dundee, Dundee, United Kingdom
| | - Sarah C Calaghan
- ¶School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - William Fuller
- From the ‡Division of Cardiovascular and Diabetes Medicine, College of Medicine, Dentistry and Nursing, University of Dundee, Dundee, United Kingdom;
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24
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Fernandez-Echevarria C, Díaz M, Ferrer I, Canerina-Amaro A, Marin R. Aβ promotes VDAC1 channel dephosphorylation in neuronal lipid rafts. Relevance to the mechanisms of neurotoxicity in Alzheimer's disease. Neuroscience 2014; 278:354-66. [PMID: 25168729 DOI: 10.1016/j.neuroscience.2014.07.079] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/23/2014] [Accepted: 07/24/2014] [Indexed: 11/25/2022]
Abstract
Voltage-dependent anion channel (VDAC) is a mitochondrial protein abundantly found in neuronal lipid rafts. In these membrane domains, VDAC is associated with a complex of signaling proteins that trigger neuroprotective responses. Loss of lipid raft integrity may result in disruption of multicomplex association and alteration of signaling responses that may ultimately promote VDAC activation. Some data have demonstrated that VDAC at the neuronal membrane may be involved in the mechanisms of amyloid beta (Aβ)-induced neurotoxicity, through yet unknown mechanisms. Aβ is generated from amyloid precursor protein (APP), and is released to the extracellular space where it may undergo self-aggregation. Aβ aggregate deposition in the form of senile plaques may lead to Alzheimer's disease (AD) neuropathology, although other pathological hallmarks (such as hyper-phosphorylated Tau deposition) also participate in this neurodegenerative process. The present study demonstrates that VDAC1 associates with APP and Aβ in lipid rafts of neurons. Interaction of VDAC1 with APP was observed in lipid rafts from the frontal and entorhinal cortex of human brains affected by AD at early stages (I-IV/0-B of Braak and Braak). Furthermore, Aβ exposure enhanced the dephosphorylation of VDAC1 that correlated with cell death. Both effects were reverted in the presence of tyrosine phosphatase inhibitors. VDAC1 dephosphorylation was corroborated in lipid rafts of AD brains. These results demonstrate that Aβ is involved in alterations of the phosphorylation state of VDAC in neuronal lipid rafts. Modulation of this channel may contribute to the development and progression of AD pathology.
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Affiliation(s)
- C Fernandez-Echevarria
- Laboratory of Cellular Neurobiology, Department of Physiology, University of La Laguna, School of Medicine, Sta. Cruz de Tenerife, Spain
| | - M Díaz
- Laboratory of Membrane Physiology and Biophysics, Department of Animal Biology, Faculty of Biology, University of La Laguna, Sta. Cruz de Tenerife, Spain
| | - I Ferrer
- Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, IDIBELL, CIBERNED, Hospitalet de Llobregat, Barcelona, Spain
| | - A Canerina-Amaro
- Laboratory of Cellular Neurobiology, Department of Physiology, University of La Laguna, School of Medicine, Sta. Cruz de Tenerife, Spain
| | - R Marin
- Laboratory of Cellular Neurobiology, Department of Physiology, University of La Laguna, School of Medicine, Sta. Cruz de Tenerife, Spain.
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25
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Loza-Huerta A, Vera-Estrella R, Darszon A, Beltrán C. Certain Strongylocentrotus purpuratus sperm mitochondrial proteins co-purify with low density detergent-insoluble membranes and are PKA or PKC-substrates possibly involved in sperm motility regulation. Biochim Biophys Acta Gen Subj 2013; 1830:5305-15. [DOI: 10.1016/j.bbagen.2013.07.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 06/24/2013] [Accepted: 07/27/2013] [Indexed: 12/14/2022]
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26
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Kim KS, Kim JS, Park JY, Suh YH, Jou I, Joe EH, Park SM. DJ-1 associates with lipid rafts by palmitoylation and regulates lipid rafts-dependent endocytosis in astrocytes. Hum Mol Genet 2013; 22:4805-17. [PMID: 23847046 DOI: 10.1093/hmg/ddt332] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Parkinson's disease (PD) is the second most common progressive neurodegenerative disease. Several genes have been associated with familial type PD, providing tremendous insights into the pathogenesis of PD. Gathering evidence supports the view that these gene products may operate through common molecular pathways. Recent reports suggest that many PD-associated gene products, such as α-synuclein, LRRK2, parkin and PINK1, associate with lipid rafts and lipid rafts may be associated with neurodegeneration. Here, we observed that DJ-1 protein also associated with lipid rafts. Palmitoylation of three cysteine residues (C46/53/106) and C-terminal region of DJ-1 were required for this association. Lipopolysaccharide (LPS) induced the localization of DJ-1 into lipid rafts in astrocytes. The LPS-TLR4 signaling was more augmented in DJ-1 knock-out astrocytes by the impairment of TLR4 endocytosis. Furthermore, lipid rafts-dependent endocytosis including the endocytosis of CD14, which play a major role in regulating TLR4 endocytosis was also impaired, but clathrin-dependent endocytosis was not. This study provides a novel function of DJ-1 in lipid rafts, which may contribute the pathogenesis of PD. Moreover, it also provides the possibility that many PD-related proteins may operate through common molecular pathways in lipid rafts.
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27
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Fowler S, Akins M, Zhou H, Figeys D, Bennett SA. The liver connexin32 interactome is a novel plasma membrane-mitochondrial signaling nexus. J Proteome Res 2013; 12:2597-610. [PMID: 23590695 PMCID: PMC3714164 DOI: 10.1021/pr301166p] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Indexed: 02/07/2023]
Abstract
Connexins are the structural subunits of gap junctions and act as protein platforms for signaling complexes. Little is known about tissue-specific connexin signaling nexuses, given significant challenges associated with affinity-purifying endogenous channel complexes to the level required for interaction analyses. Here, we used multiple subcellular fractionation techniques to isolate connexin32-enriched membrane microdomains from murine liver. We show, for the first time, that connexin32 localizes to both the plasma membrane and inner mitochondrial membrane of hepatocytes. Using a combination of immunoprecipitation-high throughput mass spectrometry, reciprocal co-IP, and subcellular fractionation methodologies, we report a novel interactome validated using null mutant controls. Eighteen connexin32 interacting proteins were identified. The majority represent resident mitochondrial proteins, a minority represent plasma membrane, endoplasmic reticulum, or cytoplasmic partners. In particular, connexin32 interacts with connexin26 and the mitochondrial protein, sideroflexin-1, at the plasma membrane. Connexin32 interaction enhances connexin26 stability. Converging bioinformatic, biochemical, and confocal analyses support a role for connexin32 in transiently tethering mitochondria to connexin32-enriched plasma membrane microdomains through interaction with proteins in the outer mitochondrial membrane, including sideroflexin-1. Complex formation increases the pool of sideroflexin-1 that is present at the plasma membrane. Together, these data identify a novel plasma membrane/mitochondrial signaling nexus in the connexin32 interactome.
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Affiliation(s)
- Stephanie
L. Fowler
- Neural
Regeneration Laboratory, Ottawa Institute of Systems Biology, Department of
Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Mark Akins
- Neural
Regeneration Laboratory, Ottawa Institute of Systems Biology, Department of
Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Hu Zhou
- Neural
Regeneration Laboratory, Ottawa Institute of Systems Biology, Department of
Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
- Shanghai Institute of Materia
Medica, Chinese Academy of Sciences, Shanghai,
China
| | - Daniel Figeys
- Neural
Regeneration Laboratory, Ottawa Institute of Systems Biology, Department of
Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Steffany A.L. Bennett
- Neural
Regeneration Laboratory, Ottawa Institute of Systems Biology, Department of
Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
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28
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Ziolkowski W, Vadhana M S D, Kaczor JJ, Olek RA, Flis DJ, Halon M, Wozniak M, Fedeli D, Carloni M, Antosiewicz J, Gabbianelli R. Exercise-induced heart mitochondrial cholesterol depletion influences the inhibition of mitochondrial swelling. Exp Physiol 2013; 98:1457-68. [PMID: 23733522 DOI: 10.1113/expphysiol.2013.073007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The significance of the reduction of the cholesterol pool in heart mitochondria after exercise is still unknown. Recently, published data have suggested that cholesterol may influence the components of mitochondrial contact site and affect mitochondrial swelling. Therefore, the aim of this study was to determine whether the decreased cholesterol content in heart mitochondria caused by prolonged swimming may provoke changes in their bioenergetics and result in an increased resistance to calcium chloride-induced mitochondrial swelling. Male Wistar rats were divided into a sedentary control group and an exercise group. The rats exercised for 3 h, burdened with an additional 3% of their body weight. Their hearts were removed immediately after completing the exercise. The left ventricle was divided and used for experiments. Mitochondrial cholesterol content, membrane fluidity and mitochondrial bioenergetics were measured in the control and exercised rat heart mitochondria. To assess whether mitochondrial modifications are linked to disruption of lipid microdomains, methyl-β-cyclodextrin, a well-known lipid microdomain-disrupting agent and cholesterol chelator, was applied to the mitochondria of the control group. Cholesterol depletion, increased membrane fluidity and increased resistance to calcium chloride-induced swelling were observed in postexercise heart crude mitochondrial fraction. Similar results were achieved in control mitochondria treated with 2% methyl-β-cyclodextrin. All of the mitochondrial bioenergetics parameters were similar between the groups. Therefore, the disruption of raft-like microdomains appears to be an adaptive change in the rat heart following exercise.
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Affiliation(s)
- Wieslaw Ziolkowski
- W. Ziolkowski: Department of Biochemistry, Gdansk University of Physical Education and Sport, 1 K. Gorskiego Street, 80-336 Gdansk, Poland.
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29
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Satori CP, Henderson MM, Krautkramer EA, Kostal V, Distefano MM, Arriaga EA. Bioanalysis of eukaryotic organelles. Chem Rev 2013; 113:2733-811. [PMID: 23570618 PMCID: PMC3676536 DOI: 10.1021/cr300354g] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Chad P. Satori
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Michelle M. Henderson
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Elyse A. Krautkramer
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Vratislav Kostal
- Tescan, Libusina trida 21, Brno, 623 00, Czech Republic
- Institute of Analytical Chemistry ASCR, Veveri 97, Brno, 602 00, Czech Republic
| | - Mark M. Distefano
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Edgar A. Arriaga
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
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30
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Ozolina NV, Nesterkina IS, Kolesnikova EV, Salyaev RK, Nurminsky VN, Rakevich AL, Martynovich EF, Chernyshov MY. Tonoplast of Beta vulgaris L. contains detergent-resistant membrane microdomains. PLANTA 2013; 237:859-71. [PMID: 23143221 DOI: 10.1007/s00425-012-1800-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 10/26/2012] [Indexed: 05/22/2023]
Abstract
The experiments conducted on tonoplast of Beta vulgaris L. roots were performed to identify detergent-resistant lipid-protein microdomains (DRMs, interpreted as lipid rafts).The presence of DRMs can be found when dynamic clustering of sphingolipids, sterols, saturated fatty acids is registered, and the insolubility of these microdomains in nonionic detergents at low temperatures is proven. The elucidation of tonoplast microdomains has been based on results obtained with the aid of high-speed centrifuging in the sucrose gradient. The experiments have shown that tonoplast microdomains are rich in sphingolipids, free sterols and saturated fatty acids (such a lipid content is also typical of lipid-protein microdomains of other membranes), while only few phospholipids are present in tonoplast microdomains. The presence of microdomains has been confirmed by fluorescence and confocal microscopy using filipin and Laurdan as fluorescent probes. The experiments with Laurdan have shown that tonoplast microdomains are characterized by a high order compared to characteristics of the rest of the tonoplast. Thus, the presence of detergent-resistant lipid-protein microdomains in the tonoplast has been demonstrated.
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Affiliation(s)
- Natalia V Ozolina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132, Lermontov St., Irkutsk, 664033, Russia.
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31
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Kristensen AR, Foster LJ. High throughput strategies for probing the different organizational levels of protein interaction networks. MOLECULAR BIOSYSTEMS 2013; 9:2201-12. [DOI: 10.1039/c3mb70135b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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32
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Raza Shaikh S, Brown DA. Models of plasma membrane organization can be applied to mitochondrial membranes to target human health and disease with polyunsaturated fatty acids. Prostaglandins Leukot Essent Fatty Acids 2013; 88:21-5. [PMID: 22464052 PMCID: PMC3391319 DOI: 10.1016/j.plefa.2012.03.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 03/08/2012] [Accepted: 03/12/2012] [Indexed: 12/14/2022]
Abstract
Bioactive n-3 polyunsaturated fatty acids (PUFA), abundant in fish oil, have potential for treating symptoms associated with inflammatory and metabolic disorders; therefore, it is essential to determine their fundamental molecular mechanisms. Recently, several labs have demonstrated the n-3 PUFA docosahexaenoic acid (DHA) exerts anti-inflammatory effects by targeting the molecular organization of plasma membrane microdomains. Here we briefly review the evidence that DHA reorganizes the spatial distribution of microdomains in several model systems. We then emphasize how models on DHA and plasma membrane microdomains can be applied to mitochondrial membranes. We discuss the role of DHA acyl chains in regulating mitochondrial lipid-protein clustering, and how these changes alter several aspects of mitochondrial function. In particular, we summarize effects of DHA on mitochondrial respiration, electron leak, permeability transition, and mitochondrial calcium handling. Finally, we conclude by postulating future experiments that will augment our understanding of DHA-dependent membrane organization in health and disease.
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Affiliation(s)
- Saame Raza Shaikh
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, 600 Moye Blvd, Greenville, NC 28590, USA.
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33
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Bayyareddy K, Zhu X, Orlando R, Adang MJ. Proteome analysis of Cry4Ba toxin-interacting Aedes aegypti lipid rafts using geLC-MS/MS. J Proteome Res 2012; 11:5843-55. [PMID: 23153095 DOI: 10.1021/pr3006167] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Lipid rafts are microdomains in the plasma membrane of eukaryotic cells. Among their many functions, lipid rafts are involved in cell toxicity caused by pore forming bacterial toxins including Bacillus thuringiensis (Bt) Cry toxins. We isolated lipid rafts from brush border membrane vesicles (BBMV) of Aedes aegypti larvae as a detergent resistant membrane (DRM) fraction on density gradients. Cholesterol, aminopeptidase (APN), alkaline phosphatase (ALP) and the raft marker flotillin were preferentially partitioned into the lipid raft fraction. When mosquitocidal Cry4Ba toxin was preincubated with BBMV, Cry4Ba localized to lipid rafts. A proteomic approach based on one-dimensional gel electrophoresis, in-gel trypsin digestion, followed by liquid chromatography-mass spectrometry (geLC-MS/MS) identified a total of 386 proteins. Of which many are typical lipid raft marker proteins including flotillins and glycosylphosphatidylinositol (GPI)-anchored proteins. Identified raft proteins were annotated in silico for functional and physicochemical characteristics. Parameters such as distribution of isoelectric point, molecular mass, and predicted post-translational modifications relevant to lipid raft proteins (GPI anchorage and myristoylation or palmitoylation) were analyzed for identified proteins in the DRM fraction. From a functional point of view, this study identified proteins implicated in Cry toxin interactions as well as membrane-associated proteins expressed in the mosquito midgut that have potential relevance to mosquito biology and vector management.
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Affiliation(s)
- Krishnareddy Bayyareddy
- Department of Entomology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, United States
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34
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Edelfosine and perifosine disrupt hepatic mitochondrial oxidative phosphorylation and induce the permeability transition. Mitochondrion 2012; 13:25-35. [PMID: 23164800 DOI: 10.1016/j.mito.2012.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/02/2012] [Accepted: 11/07/2012] [Indexed: 12/25/2022]
Abstract
Edelfosine and perifosine are alkylphospholipids that have been intensively studied as potential antitumor agents. Apoptotic cell death caused by these two compounds is mediated, at least in part, through mitochondria. Additionally, previous works demonstrated that edelfosine induces changes in mitochondrial membrane permeability that are somehow reduced by using cyclosporin A. Therefore, the objective of the present study was not only to confirm mitochondrial permeability transition but also identify direct effects of both ether lipids on mitochondrial hepatic fractions, namely on mitochondrial oxidative phosphorylation and generation of hydrogen peroxide (H(2)O(2)) through the respiratory chain. Results show that edelfosine and perifosine inhibit mitochondrial respiration and decrease transmembrane electric potential. However, despite these effects, edelfosine and perifosine were still able to induce mitochondrial permeability transition in non-energized mitochondria. Interestingly, edelfosine decreased H(2)O(2) production through the respiratory chain. In conclusion, the present work demonstrates previously unknown alterations of mitochondrial physiology directly induced by edelfosine and perifosine. The study is relevant in the understanding of mitochondrial-target effects of both compounds, as well as to acknowledge possible toxic responses in non-tumor organs.
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35
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Upregulated function of mitochondria-associated ER membranes in Alzheimer disease. EMBO J 2012; 31:4106-23. [PMID: 22892566 PMCID: PMC3492725 DOI: 10.1038/emboj.2012.202] [Citation(s) in RCA: 476] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 06/28/2012] [Indexed: 12/12/2022] Open
Abstract
Alzheimer disease (AD) associated (gamma)-secretase components presenilin-1 and -2 accumulate in MAM, an LR-like ER subcompartment connected to mitochondria. MAM function increases in patients with familial or sporadic AD and may be linked to AD pathogenesis. Alzheimer disease (AD) is associated with aberrant processing of the amyloid precursor protein (APP) by γ-secretase, via an unknown mechanism. We recently showed that presenilin-1 and -2, the catalytic components of γ-secretase, and γ-secretase activity itself, are highly enriched in a subcompartment of the endoplasmic reticulum (ER) that is physically and biochemically connected to mitochondria, called mitochondria-associated ER membranes (MAMs). We now show that MAM function and ER–mitochondrial communication—as measured by cholesteryl ester and phospholipid synthesis, respectively—are increased significantly in presenilin-mutant cells and in fibroblasts from patients with both the familial and sporadic forms of AD. We also show that MAM is an intracellular detergent-resistant lipid raft (LR)-like domain, consistent with the known presence of presenilins and γ-secretase activity in rafts. These findings may help explain not only the aberrant APP processing but also a number of other biochemical features of AD, including altered lipid metabolism and calcium homeostasis. We propose that upregulated MAM function at the ER–mitochondrial interface, and increased cross-talk between these two organelles, may play a hitherto unrecognized role in the pathogenesis of AD.
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36
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Minogue S, Waugh MG. Lipid rafts, microdomain heterogeneity and inter-organelle contacts: impacts on membrane preparation for proteomic studies. Biol Cell 2012; 104:618-27. [PMID: 22694059 DOI: 10.1111/boc.201200020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 06/08/2012] [Indexed: 12/20/2022]
Abstract
In recent years, there has been considerable interest in mapping the protein content of isolated organelles using mass spectrometry. However, many subcellular compartments are highly dynamic with diverse and intricate architectures that are not always preserved during membrane isolation procedures. Furthermore, lateral heterogeneities in intra-membrane lipid and protein concentrations underlie the formation of membrane microdomains, trafficking vesicles and inter-membrane contacts. These complexities in membrane organisation have important consequences for the design of membrane preparation strategies and test the very concept of organelle purity. We illustrate how some of these biological considerations are relevant to membrane preparation and assess the numerous potential pitfalls in attempting to purify organelles from mammalian cells.
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Affiliation(s)
- Shane Minogue
- Centre for Molecular Cell Biology, UCL, Institute of Liver and Digestive Health, Royal Free Campus, UCL, London NW3 2PF, United Kingdom
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37
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Thiede A, Gellerich FN, Schönfeld P, Siemen D. Complex effects of 17β-estradiol on mitochondrial function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1747-53. [PMID: 22414665 DOI: 10.1016/j.bbabio.2012.02.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/23/2012] [Accepted: 02/25/2012] [Indexed: 01/01/2023]
Abstract
Existing literature on estradiol indicates that it affects mitochondrial functions at low micromolar concentrations. Particularly blockade of the permeability transition pore (PTP) or modulation of the enzymatic activity of one or more complexes of the respiratory chain were suspicious. We prepared mitoplasts from rat liver mitochondria (RLM) to study by single-channel patch-clamp techniques the PTP, and from rat astrocytes to study the potassium BK-channel said to modulate the PTP. Additionally, we measured respiration of intact RLM. After application of 17β-estradiol (βE) our single-channel results reveal a transient increase of activity of both, the BK-channel and the PTP followed by their powerful inhibition. Respiration measurements demonstrate inhibition of the Ca(2+)-induced permeability transition, as well, though only at higher concentrations (≥30μM). At lower concentrations, we observed an increase of endogenous- and state 2-respiration. Furthermore, we show that βE diminishes the phosphorylating respiration supported by complex I-substrates (glutamate/malate) or by the complex II-substrate succinate. Taken together the results suggest that βE affects mitochondria by several modes, including partial inhibition of the activities of ion channels of the inner membrane and of respiration. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).
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Affiliation(s)
- Anika Thiede
- Dept. of Neurology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
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38
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Buschow SI, Lasonder E, Szklarczyk R, Oud MM, de Vries IJM, Figdor CG. Unraveling the human dendritic cell phagosome proteome by organellar enrichment ranking. J Proteomics 2011; 75:1547-62. [PMID: 22146474 DOI: 10.1016/j.jprot.2011.11.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 11/18/2011] [Accepted: 11/22/2011] [Indexed: 12/24/2022]
Abstract
Dendritic cells (DC) take up pathogens through phagocytosis and process them into protein and lipid fragments for presentation to T cells. So far, the proteome of the human DC phagosome, a detrimental compartment for antigen processing and presentation as well as for DC activation, remains largely uncharacterized. Here we have analyzed the protein composition of phagosomes from human monocyte-derived DC. For LC-MS/MS analysis we purified phagosomes from DC using latex beads targeted to DC-SIGN, and quantified proteins using a label-free method. We used organellar enrichment ranking (OER) to select proteins with a high potential to be relevant for phagosome function. The method compares phagosome protein abundance with protein abundance in whole DC. Phagosome enrichment indicates specific recruitment to the phagosome rather than co-purification or passive incorporation. Using OER we extracted the most enriched proteins that we further complemented with functionally associated proteins to define a set of 90 phagosomal proteins that included many proteins with established relevance on DC phagosomes as well as high potential novel candidates. We already experimentally confirmed phagosomal recruitment of Galectin-9, which has not been previously associated with phagocytosis, to both bead and pathogen containing phagosomes, suggesting a role for Galectin-9 in DC phagocytosis.
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Affiliation(s)
- Sonja I Buschow
- Department of Tumor Immunology at the Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Postbox 9101, 6500 HB Nijmegen, The Netherlands
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39
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Shaikh SR. Biophysical and biochemical mechanisms by which dietary N-3 polyunsaturated fatty acids from fish oil disrupt membrane lipid rafts. J Nutr Biochem 2011; 23:101-5. [PMID: 22137258 DOI: 10.1016/j.jnutbio.2011.07.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 07/08/2011] [Accepted: 07/11/2011] [Indexed: 12/11/2022]
Abstract
N-3 polyunsaturated fatty acids (PUFAs) from fish oil exert their functional effects by targeting multiple mechanisms. One mechanism to emerge in the past decade is the ability of n-3 PUFA acyl chains to perturb the molecular organization of plasma membrane sphingolipid/cholesterol-enriched lipid raft domains. These domains are nanometer-scale assemblies that coalesce to compartmentalize select proteins for optimal function. Here we review recent evidence on how n-3 PUFAs modify lipid rafts from biophysical and biochemical experiments from several different model systems. A central theme emerges from these studies. N-3 PUFA acyl chains display tremendous conformational flexibility and a low affinity for cholesterol and saturated acyl chains. This unique flexibility of n-3 PUFA acyl chains impacts the organization of inner and outer leaflet lipid rafts by disrupting acyl chain packing and molecular order within rafts. Ultimately, the disruption in raft organization has consequences for protein clustering and thereby signaling. Overall, elucidating the complex mechanisms by which n-3 PUFA acyl chains reorganize membrane architecture will enhance the translation of these fatty acids into the clinic for treating several diseases.
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Affiliation(s)
- Saame Raza Shaikh
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834, USA.
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40
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Jin S, Zhou F, Katirai F, Li PL. Lipid raft redox signaling: molecular mechanisms in health and disease. Antioxid Redox Signal 2011; 15:1043-83. [PMID: 21294649 PMCID: PMC3135227 DOI: 10.1089/ars.2010.3619] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Lipid rafts, the sphingolipid and cholesterol-enriched membrane microdomains, are able to form different membrane macrodomains or platforms upon stimulations, including redox signaling platforms, which serve as a critical signaling mechanism to mediate or regulate cellular activities or functions. In particular, this raft platform formation provides an important driving force for the assembling of NADPH oxidase subunits and the recruitment of other related receptors, effectors, and regulatory components, resulting, in turn, in the activation of NADPH oxidase and downstream redox regulation of cell functions. This comprehensive review attempts to summarize all basic and advanced information about the formation, regulation, and functions of lipid raft redox signaling platforms as well as their physiological and pathophysiological relevance. Several molecular mechanisms involving the formation of lipid raft redox signaling platforms and the related therapeutic strategies targeting them are discussed. It is hoped that all information and thoughts included in this review could provide more comprehensive insights into the understanding of lipid raft redox signaling, in particular, of their molecular mechanisms, spatial-temporal regulations, and physiological, pathophysiological relevances to human health and diseases.
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Affiliation(s)
- Si Jin
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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41
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Zheng YZ, Boscher C, Inder KL, Fairbank M, Loo D, Hill MM, Nabi IR, Foster LJ. Differential impact of caveolae and caveolin-1 scaffolds on the membrane raft proteome. Mol Cell Proteomics 2011; 10:M110.007146. [PMID: 21753190 PMCID: PMC3205860 DOI: 10.1074/mcp.m110.007146] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Caveolae, a class of cholesterol-rich lipid rafts, are smooth invaginations of the plasma membrane whose formation in nonmuscle cells requires caveolin-1 (Cav1). The recent demonstration that Cav1-associated cavin proteins, in particular PTRF/cavin-1, are also required for caveolae formation supports a functional role for Cav1 independently of caveolae. In tumor cells deficient for Golgi β-1,6N-acetylglucosaminyltransferase V (Mgat5), reduced Cav1 expression is associated not with caveolae but with oligomerized Cav1 domains, or scaffolds, that functionally regulate receptor signaling and raft-dependent endocytosis. Using subdiffraction-limit microscopy, we show that Cav1 scaffolds are homogenous subdiffraction-limit sized structures whose size distribution differs from that of Cav1 in caveolae expressing cells. These cell lines displaying differing Cav1/caveolae phenotypes are effective tools for probing the structure and composition of caveolae. Using stable isotope labeling by amino acids in cell culture, we are able to quantitatively distinguish the composition of caveolae from the background of detergent-resistant membrane proteins and show that the presence of caveolae enriches the protein composition of detergent-resistant membrane, including the recruitment of multiple heterotrimeric G-protein subunits. These data were further supported by analysis of immuno-isolated Cav1 domains and of methyl-β-cyclodextrin-disrupted detergent-resistant membrane. Our data show that loss of caveolae results in a dramatic change to the membrane raft proteome and that this change is independent of Cav1 expression. The proteomics data, in combination with subdiffraction-limit microscopy, indicates that noncaveolar Cav1 domains, or scaffolds are structurally and functionally distinct from caveolae and differentially impact on the molecular composition of lipid rafts.
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Affiliation(s)
- Yu Zi Zheng
- Centre for High-Throughput Biology and Department of Biochemistry and Molecular Biology, 2125 East Mall, University of British Columbia, Vancouver, BC, Canada
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42
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Ozolina NV, Nesterkina IS, Nurminsky VN, Stepanov AV, Kolesnikova EV, Gurina VV, Salyaev RK. Recognition of lipid-protein rafts in vacuolar membrane. DOKL BIOCHEM BIOPHYS 2011; 438:120-2. [PMID: 21725887 DOI: 10.1134/s1607672911030033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Indexed: 11/23/2022]
Affiliation(s)
- N V Ozolina
- Siberian Institute of Plant Physiology and Biochemistry, Russian Academy of Sciences, ul. Lermontova 132, Irkutsk, 664033, Russia
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43
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Rayapureddi JP, Tomamichel WJ, Walton ST, Payne RM. TAT fusion protein transduction into isolated mitochondria is accelerated by sodium channel inhibitors. Biochemistry 2011; 49:9470-9. [PMID: 20925426 DOI: 10.1021/bi101057v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Stringent control of ion and protein transport across the mitochondrial membranes is required to maintain mitochondrial function and biogenesis. In particular, the inner mitochondrial membrane is generally impermeable to proteins entering the matrix except via tightly regulated protein import mechanisms. Recently, cell penetrant peptides have been shown to move across the inner mitochondrial membrane in a manner suggesting an independent mechanism. HIV-1 transactivator of transcription (TAT) is an arginine-rich cell penetrant peptide, 47YGRKKRRQRRR57, which can transduce full-length proteins not only across the cell membrane but also into intracellular organelles. In this study, we investigated the ability of a TAT-containing protein to move into the mitochondrial matrix. Using a novel FACS assay for isolated, purified mitochondria, we show that TAT can deliver a modified fluorescent protein, mMDH-GFP, to the matrix of mitochondria and it is subsequently processed by the matrix peptidases. In addition, transduction of TAT-mMDH-GFP into mitochondria is independent of canonical protein import pathways as well as mitochondrial membrane potential. In direct contrast to published reports regarding the cell membrane where the sodium channel inhibitor, amiloride, blocks endocytosis and inhibits TAT transduction, TAT transduction into mitochondria is markedly increased by this same sodium channel inhibitor. These results confirm that the cell penetrant peptide, TAT, can readily transduce a protein cargo into the mitochondrial matrix. These results also demonstrate a novel role for mitochondrial sodium channels in mediating TAT transduction into mitochondria that is independent of endocytotic mechanisms. The mechanism of TAT transduction into mitochondria therefore is distinctly different from transduction across the cell membrane.
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44
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Sommer B, Dingersen T, Gamroth C, Schneider SE, Rubert S, Krüger J, Dietz KJ. CELLmicrocosmos 2.2 MembraneEditor: a modular interactive shape-based software approach to solve heterogeneous membrane packing problems. J Chem Inf Model 2011; 51:1165-82. [PMID: 21504163 DOI: 10.1021/ci1003619] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
New perspectives have been developed to understand the processes of modeling heterogeneous membranes. These are crucial steps prior to applying advanced techniques like molecular dynamic simulations of whole membrane systems. Lipid, protein, and membrane packing problems are addressed based on biochemical properties in combination with computational optimization techniques. The CELLmicrocosmos 2.2 MembraneEditor (CmME) is introduced as an appropriate framework to handle such problems by offering diverse algorithmic approaches. Its algorithm plug-in-interface enables modelers to generate problem-specific algorithms. Good solutions concerning runtime and lipid density are realized by focusing on the outer shapes of the PDB-based molecules. Application cases are presented like the publication-based modeling of inner and outer mitochondrial membrane-fragments, semiautomatic incorporation of proteins, and the assembly of rafts. Concerning geometrical aspects of the lipids, the achieved results are consistent with experimental observations related to lipid densities and distributions. Finally, two membranes simulated with GROMACS are analyzed and compared: the first is generated with conventional scripting techniques, the second with the CmME Distributor algorithm. The examples prove that CmME is a valuable and versatile tool for a broad set of applications in analysis and visualization of biomembranes.
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Affiliation(s)
- Björn Sommer
- Bio-/Medical Informatics Department, Bielefeld University , D-33615 Bielefeld, Germany
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45
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Kim BW, Lee CS, Yi JS, Lee JH, Lee JW, Choo HJ, Jung SY, Kim MS, Lee SW, Lee MS, Yoon G, Ko YG. Lipid raft proteome reveals that oxidative phosphorylation system is associated with the plasma membrane. Expert Rev Proteomics 2011; 7:849-66. [PMID: 21142887 DOI: 10.1586/epr.10.87] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Although accumulating proteomic analyses have supported the fact that mitochondrial oxidative phosphorylation (OXPHOS) complexes are localized in lipid rafts, which mediate cell signaling, immune response and host-pathogen interactions, there has been no in-depth study of the physiological functions of lipid-raft OXPHOS complexes. Here, we show that many subunits of OXPHOS complexes were identified from the lipid rafts of human adipocytes, C2C12 myotubes, Jurkat cells and surface biotin-labeled Jurkat cells via shotgun proteomic analysis. We discuss the findings of OXPHOS complexes in lipid rafts, the role of the surface ATP synthase complex as a receptor for various ligands and extracellular superoxide generation by plasma membrane oxidative phosphorylation complexes.
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Affiliation(s)
- Bong-Woo Kim
- College of Life Sciences and Biotechnology, Korea University, 1, 5-ka, Anam-dong, Sungbuk-ku, Seoul, Korea
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46
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Schug ZT, Gonzalvez F, Houtkooper RH, Vaz FM, Gottlieb E. BID is cleaved by caspase-8 within a native complex on the mitochondrial membrane. Cell Death Differ 2011; 18:538-48. [PMID: 21072056 PMCID: PMC3132005 DOI: 10.1038/cdd.2010.135] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 09/09/2010] [Accepted: 09/22/2010] [Indexed: 11/09/2022] Open
Abstract
Caspase-8 stably inserts into the mitochondrial outer membrane during extrinsic apoptosis. Inhibition of caspase-8 enrichment on the mitochondria impairs caspase-8 activation and prevents apoptosis. However, the function of active caspase-8 on the mitochondrial membrane remains unknown. In this study, we have identified a native complex containing caspase-8 and BID on the mitochondrial membrane, and showed that death receptor activation by Fas or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induced the cleavage of BID (tBID formation) within this complex. tBID then shifted to separate mitochondria-associated complexes that contained other BCL-2 family members, such as BAK and BCL-X(L). We report that cells stabilize active caspase-8 on the mitochondria in order to specifically target mitochondria-associated BID, and that BID cleavage on the mitochondria is essential for caspase-8-induced cytochrome c release. Our findings indicate that during extrinsic apoptosis, caspase-8 can specifically target BID where it is mostly needed, on the surface of mitochondria.
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Affiliation(s)
- Z T Schug
- Laboratory of Apoptosis and Tumour Metabolism, Cancer Research UK, The Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
| | - F Gonzalvez
- Laboratory of Apoptosis and Tumour Metabolism, Cancer Research UK, The Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
| | - R H Houtkooper
- Laboratory Genetic Metabolic Diseases, University of Amsterdam, Academic Medical Center, Amsterdam, The Netherlands
| | - F M Vaz
- Laboratory Genetic Metabolic Diseases, University of Amsterdam, Academic Medical Center, Amsterdam, The Netherlands
| | - E Gottlieb
- Laboratory of Apoptosis and Tumour Metabolism, Cancer Research UK, The Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
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47
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Asano A, Nelson JL, Zhang S, Travis AJ. Characterization of the proteomes associating with three distinct membrane raft sub-types in murine sperm. Proteomics 2011; 10:3494-505. [PMID: 20815087 DOI: 10.1002/pmic.201000002] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mammalian sperm are transcriptionally and translationally inactive. To meet changing needs in the epididymis and female tract, they rely heavily on post-translational modifications and protein acquisition/degradation. Membrane rafts are sterol and sphingolipid-enriched micro-domains that organize and regulate various pathways. Rafts have significance in sperm by transducing the stimulus of sterol efflux into changes in intracellular signaling that confer fertilization competence. We recently characterized three biochemically distinct sub-types of sperm rafts, and now present profiles for proteins targeting to and associating with these sub-types, along with a fraction largely comprised of "non-raft" domains. Proteomics analysis using a gel-based LC-MS/MS approach identified 190 strictly validated proteins in the raft sub-types. Interestingly, many of these are known to be expressed in the epididymis, where sperm membrane composition matures. To investigate potential roles for rafts in epididymal protein acquisition, we compared the expression and localization of two different sterol-interacting proteins, apolipoprotein-A1 (apoA1) and prominin-1 (prom1) in sperm from different zones. We found that apoA1 was gradually added to the plasma membrane overlying the acrosome, whereas prom1 was not, suggesting different mechanisms for raft protein acquisition. Our results define raft-associating proteins, demonstrate functional similarities and differences among raft sub-types, and provide insights into raft-mediated epididymal protein acquisition.
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Affiliation(s)
- Atsushi Asano
- The Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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48
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Waugh MG, Chu KME, Clayton EL, Minogue S, Hsuan JJ. Detergent-free isolation and characterization of cholesterol-rich membrane domains from trans-Golgi network vesicles. J Lipid Res 2010; 52:582-9. [PMID: 21191144 DOI: 10.1194/jlr.d012807] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cholesterol is an abundant lipid of the trans-Golgi network (TGN) and of certain endosomal membranes where cholesterol-rich microdomains are important in the organization and compartmentalization of vesicular trafficking. Here we describe the development of a rapid method to isolate a cholesterol-rich endomembrane fraction. We show that widely used subcellular fractionation techniques incompletely separate cholesterol-rich membranes, such as the TGN, from organelles, such as late endosomes and lysosomes. To address this issue, we devised a new subcellular fractionation scheme involving two rounds of velocity centrifugation, membrane sonication, and discontinuous sucrose density gradient centrifugation. This strategy resulted in the isolation of a cholesterol and GM1 glycosphingolipid-enriched membrane fraction that was completely cleared of plasma membrane, endoplasmic reticulum, and mitochondria. This buoyant fraction was enriched for the TGN and recycling endosome proteins Rab11 and syntaxin-6, and it was well resolved from cis-Golgi and early and late endosomal membranes. We demonstrate that this technique can give useful insights into the compartmentation of phosphoinositide synthesis, and it facilitates the isolation of cholesterol-rich membranes from a population of TGN-trafficking vesicles.
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Affiliation(s)
- Mark G Waugh
- Centre for Molecular Cell Biology, Department of Inflammation, Division of Medicine, University College London, Royal Free Campus, Rowland Hill Street, London, United Kingdom NW3 2PF.
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49
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Vantourout P, Radojkovic C, Lichtenstein L, Pons V, Champagne E, Martinez LO. Ecto-F 1-ATPase: A moonlighting protein complex and an unexpected apoA-I receptor. World J Gastroenterol 2010; 16:5925-35. [PMID: 21157968 PMCID: PMC3007107 DOI: 10.3748/wjg.v16.i47.5925] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial ATP synthase has been recently detected at the surface of different cell types, where it is a high affinity receptor for apoA-I, the major protein component in high density lipoproteins (HDL). Cell surface ATP synthase (namely ecto-F1-ATPase) expression is related to different biological effects, such as regulation of HDL uptake by hepatocytes, endothelial cell proliferation or antitumor activity of Vγ9/Vδ2 T lymphocytes. This paper reviews the recently discovered functions and regulations of ecto-F1-ATPase. Particularly, the role of the F1-ATPase pathway(s) in HDL-cholesterol uptake and apoA-I-mediated endothelial protection suggests its potential importance in reverse cholesterol transport and its regulation might represent a potential therapeutic target for HDL-related therapy for cardiovascular diseases. Therefore, it is timely for us to better understand how this ecto-enzyme and downstream pathways are regulated and to develop pharmacologic interventions.
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50
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Rao W, Isaac RE, Keen JN. An analysis of the Caenorhabditis elegans lipid raft proteome using geLC-MS/MS. J Proteomics 2010; 74:242-53. [PMID: 21070894 DOI: 10.1016/j.jprot.2010.11.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 10/20/2010] [Accepted: 11/02/2010] [Indexed: 11/16/2022]
Abstract
Lipid rafts are microdomains of the phospholipid bilayer, proposed to form semi-stable "islands" that act as a platform for several important cellular processes; major classes of raft-resident proteins include signalling proteins and glycosylphosphatidylinositol (GPI)-anchored proteins. Proteomic studies into lipid rafts have been mainly carried out in mammalian cell lines and single cell organisms. The nematode Caenorhabditis elegans, the model organism with a well-defined developmental profile, is ideally suited for the study of this subcellular locale in a complex developmental context. A study of the lipid raft proteome of C. elegans is presented here. A total of 44 proteins were identified from the lipid raft fraction using geLC-MS/MS, of which 40 have been determined to be likely raft proteins after analysis of predicted functions. Prediction of GPI-anchoring of the proteins found 21 to be potentially modified in this way, two of which were experimentally confirmed to be GPI-anchored. This work is the first reported study of the lipid raft proteome in C. elegans. The results show that raft proteins, including numerous GPI-anchored proteins, may have a variety of potentially important roles within the nematode, and will hopefully lead to C. elegans becoming a useful model for the study of lipid rafts.
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Affiliation(s)
- Wei Rao
- Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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