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Drolia R, Bryant DB, Tenguria S, Jules-Culver ZA, Thind J, Amelunke B, Liu D, Gallina NLF, Mishra KK, Samaddar M, Sawale MR, Mishra DK, Cox AD, Bhunia AK. Listeria adhesion protein orchestrates caveolae-mediated apical junctional remodeling of epithelial barrier for Listeria monocytogenes translocation. mBio 2024; 15:e0282123. [PMID: 38376160 PMCID: PMC10936185 DOI: 10.1128/mbio.02821-23] [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: 10/16/2023] [Accepted: 01/09/2024] [Indexed: 02/21/2024] Open
Abstract
The cellular junctional architecture remodeling by Listeria adhesion protein-heat shock protein 60 (LAP-Hsp60) interaction for Listeria monocytogenes (Lm) passage through the epithelial barrier is incompletely understood. Here, using the gerbil model, permissive to internalin (Inl) A/B-mediated pathways like in humans, we demonstrate that Lm crosses the intestinal villi at 48 h post-infection. In contrast, the single isogenic (lap- or ΔinlA) or double (lap-ΔinlA) mutant strains show significant defects. LAP promotes Lm translocation via endocytosis of cell-cell junctional complex in enterocytes that do not display luminal E-cadherin. In comparison, InlA facilitates Lm translocation at cells displaying apical E-cadherin during cell extrusion and mucus expulsion from goblet cells. LAP hijacks caveolar endocytosis to traffic integral junctional proteins to the early and recycling endosomes. Pharmacological inhibition in a cell line and genetic knockout of caveolin-1 in mice prevents LAP-induced intestinal permeability, junctional endocytosis, and Lm translocation. Furthermore, LAP-Hsp60-dependent tight junction remodeling is also necessary for InlA access to E-cadherin for Lm intestinal barrier crossing in InlA-permissive hosts. IMPORTANCE Listeria monocytogenes (Lm) is a foodborne pathogen with high mortality (20%-30%) and hospitalization rates (94%), particularly affecting vulnerable groups such as pregnant women, fetuses, newborns, seniors, and immunocompromised individuals. Invasive listeriosis involves Lm's internalin (InlA) protein binding to E-cadherin to breach the intestinal barrier. However, non-functional InlA variants have been identified in Lm isolates, suggesting InlA-independent pathways for translocation. Our study reveals that Listeria adhesion protein (LAP) and InlA cooperatively assist Lm entry into the gut lamina propria in a gerbil model, mimicking human listeriosis in early infection stages. LAP triggers caveolin-1-mediated endocytosis of critical junctional proteins, transporting them to early and recycling endosomes, facilitating Lm passage through enterocytes. Furthermore, LAP-Hsp60-mediated junctional protein endocytosis precedes InlA's interaction with basolateral E-cadherin, emphasizing LAP and InlA's cooperation in enhancing Lm intestinal translocation. This understanding is vital in combating the severe consequences of Lm infection, including sepsis, meningitis, encephalitis, and brain abscess.
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Affiliation(s)
- Rishi Drolia
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, Indiana, USA
- Department of Biological Science, Old Dominion University, Norfolk, Virginia, USA
- Department of Biological Science, Eastern Kentucky University, Richmond, Kentucky, USA
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA
| | - Donald B. Bryant
- Department of Biological Science, Eastern Kentucky University, Richmond, Kentucky, USA
| | - Shivendra Tenguria
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA
| | - Zuri A. Jules-Culver
- Department of Biological Science, Old Dominion University, Norfolk, Virginia, USA
| | - Jessie Thind
- Department of Biological Science, Eastern Kentucky University, Richmond, Kentucky, USA
| | - Breanna Amelunke
- Department of Biological Science, Eastern Kentucky University, Richmond, Kentucky, USA
| | - Dongqi Liu
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA
| | - Nicholas L. F. Gallina
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA
| | - Krishna K. Mishra
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, Indiana, USA
| | - Manalee Samaddar
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA
| | - Manoj R. Sawale
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, Indiana, USA
| | - Dharmendra K. Mishra
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, Indiana, USA
| | - Abigail D. Cox
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA
| | - Arun K. Bhunia
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA
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2
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Hanashima S, Ikeda R, Matsubara Y, Yasuda T, Tsuchikawa H, Slotte JP, Murata M. Effect of cholesterol on the lactosylceramide domains in phospholipid bilayers. Biophys J 2022; 121:1143-1155. [PMID: 35218738 PMCID: PMC9034317 DOI: 10.1016/j.bpj.2022.02.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/22/2021] [Accepted: 02/22/2022] [Indexed: 11/02/2022] Open
Abstract
Lactosylceramide (LacCer) in the plasma membranes of immune cells is an important lipid for signaling in innate immunity through the formation of LacCer-rich domains together with cholesterol (Cho). However, the properties of the LacCer domains formed in multicomponent membranes remain unclear. In this study, we examined the properties of the LacCer domains formed in Cho containing 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) membranes by deuterium solid-state NMR and fluorescence lifetimes. The potent affinity of LacCer-LacCer (homophilic interaction) is known to induce a thermally stable gel phase in the unitary LacCer bilayer. In LacCer/Cho binary membranes, Cho gradually destabilized the LacCer gel phase to form the liquid-ordered (Lo) phase by its potent order effect. In the LacCer/POPC binary systems without Cho, the 2H NMR spectra of 10',10'-d2-LacCer and 18',18',18'-d3-LacCer probes revealed that LacCer was poorly miscible with POPC in the membranes and formed stable gel phases without being distributed in the liquid crystalline (Ld) domain. The lamellar structure of the LacCer/POPC membrane was gradually disrupted at around 60 °C, while the addition of Cho increased the thermal stability of the lamellarity. Furthermore, the area of the LacCer gel phase and its chain order were decreased in the LacCer/POPC/Cho ternary membranes, while the Lo domain, which was observed in the LacCer/Cho binary membrane, was not observed. Cho surrounding the LacCer gel domain liberated LacCer and facilitated forming the submicron- to nano-scale small domains in the Ld domain of the LacCer/POPC/Cho membranes, as revealed by the fluorescence lifetimes of trans-parinaric acid (tPA) and tPA-LacCer. Our findings on the membrane properties of the LacCer domains, particularly in the presence of Cho, would help elucidate the properties of the LacCer domains in biological membranes.
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Affiliation(s)
- Shinya Hanashima
- Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043, Japan.
| | - Ryuji Ikeda
- Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043, Japan
| | - Yuki Matsubara
- Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043, Japan
| | - Tomokazu Yasuda
- Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043, Japan
| | - Hiroshi Tsuchikawa
- Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043, Japan
| | - J Peter Slotte
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Tykistökatu 6 A, FIN 20520 Turku, Finland
| | - Michio Murata
- Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043, Japan; JST ERATO, Lipid Active Structure Project, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043, Japan
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3
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Yano Y, Hanashima S, Tsuchikawa H, Yasuda T, Slotte JP, London E, Murata M. Sphingomyelins and ent-Sphingomyelins Form Homophilic Nano-Subdomains within Liquid Ordered Domains. Biophys J 2020; 119:539-552. [PMID: 32710823 PMCID: PMC7399500 DOI: 10.1016/j.bpj.2020.06.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/19/2020] [Accepted: 06/26/2020] [Indexed: 12/29/2022] Open
Abstract
Sphingomyelin (SM), a major component of small domains (or lipid rafts) in mammalian cell membranes, forms a liquid-ordered phase in the presence of cholesterol (Cho). However, the nature of molecular interactions within the ordered SM/Cho phase remains elusive. We previously revealed that stearoyl-SM (SSM) and its enantiomer (ent-SSM) separately form nano-subdomains within the liquid-ordered phase involving homophilic SSM-SSM and ent-SSM-ent-SSM interactions. In this study, the details of the subdomain formation by SSMs at the nanometer range were examined using Förster resonance energy transfer (FRET) measurements in lipid bilayers containing SSM and ent-SSM, dioleoyl-phosphatidylcholine and Cho. Although microscopy detected a stereochemical effect on partition coefficient favoring stereochemically homophilic interactions in the liquid-ordered state, it showed no significant difference in large-scale liquid-ordered domain formation by the two stereoisomers. In contrast to the uniform domains seen microscopy, FRET analysis using fluorescent donor- and acceptor-labeled SSM showed distinct differences in SM and ent-SM colocalization within nanoscale distances. Donor- and acceptor-labeled SSM showed significantly higher FRET efficiency than did donor-labeled SSM and acceptor-labeled ent-SSM in lipid vesicles composed of “racemic” (1:1) mixtures of SSM/ent-SSM with dioleoylphosphatidylcholine and Cho. The difference in FRET efficiency indicated that SSM and ent-SSM assemble to form separate nano-subdomains. The average size of the subdomains decreased as temperature increased, and at physiological temperatures, the subdomains were found to have a single-digit nanometer radius. These results suggest that (even in the absence of ent-SM) SM-SM interactions play a crucial role in forming nano-subdomains within liquid-ordered domains and may be a key feature of lipid microdomains (or rafts) in biological membranes.
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Affiliation(s)
- Yo Yano
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan; ERATO, Lipid Active Structure Project, Japan Science and Technology Agency, Graduate School of Science, Osaka University, Osaka, Japan
| | - Shinya Hanashima
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan
| | - Hiroshi Tsuchikawa
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan
| | - Tomokazu Yasuda
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan
| | - J Peter Slotte
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Erwin London
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York.
| | - Michio Murata
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan; ERATO, Lipid Active Structure Project, Japan Science and Technology Agency, Graduate School of Science, Osaka University, Osaka, Japan.
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4
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Chen YJ, Liu X, Tsai B. SV40 Hijacks Cellular Transport, Membrane Penetration, and Disassembly Machineries to Promote Infection. Viruses 2019; 11:v11100917. [PMID: 31590347 PMCID: PMC6832212 DOI: 10.3390/v11100917] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/23/2019] [Accepted: 09/23/2019] [Indexed: 12/22/2022] Open
Abstract
During entry, a virus must be transported through the endomembrane system of the host cell, penetrate a cellular membrane, and undergo capsid disassembly, to reach the cytosol and often the nucleus in order to cause infection. To do so requires the virus to coordinately exploit the action of cellular membrane transport, penetration, and disassembly machineries. How this is accomplished remains enigmatic for many viruses, especially for viruses belonging to the nonenveloped virus family. In this review, we present the current model describing infectious entry of the nonenveloped polyomavirus (PyV) SV40. Insights from SV40 entry are likely to provide strategies to combat PyV-induced diseases, and to illuminate cellular trafficking, membrane transport, and disassembly mechanisms.
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Affiliation(s)
- Yu-Jie Chen
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA.
| | - Xiaofang Liu
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA.
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA.
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5
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Singh RD, Hillestad ML, Livia C, Li M, Alekseev AE, Witt TA, Stalboerger PG, Yamada S, Terzic A, Behfar A. M 3RNA Drives Targeted Gene Delivery in Acute Myocardial Infarction. Tissue Eng Part A 2018; 25:145-158. [PMID: 30047313 DOI: 10.1089/ten.tea.2017.0445] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
IMPACT STATEMENT The M3RNA (microencapsulated modified messenger RNA) platform is an approach to deliver messenger RNA (mRNA) in vivo, achieving a nonintegrating and viral-free approach to gene therapy. This technology was, in this study, tested for its utility in the myocardium, providing a unique avenue for targeted gene delivery into the freshly infarcted myocardial tissue. This study provides the evidentiary basis for the use of M3RNA in the heart through depiction of its performance in cultured cells, healthy rodent myocardium, and acutely injured porcine hearts. By testing the technology in large animal models of infarction, compatibility of M3RNA with current coronary intervention procedures was verified.
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Affiliation(s)
- Raman Deep Singh
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Matthew L Hillestad
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Christopher Livia
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota.,3 Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Mark Li
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota.,3 Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Alexey E Alekseev
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota.,4 Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Moscow, Russia
| | - Tyra A Witt
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Paul G Stalboerger
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Satsuki Yamada
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Andre Terzic
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota.,3 Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Atta Behfar
- 1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.,2 VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota.,3 Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
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6
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Otis JP, Shen MC, Quinlivan V, Anderson JL, Farber SA. Intestinal epithelial cell caveolin 1 regulates fatty acid and lipoprotein cholesterol plasma levels. Dis Model Mech 2017; 10:283-295. [PMID: 28130355 PMCID: PMC5374320 DOI: 10.1242/dmm.027300] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 01/23/2017] [Indexed: 12/16/2022] Open
Abstract
Caveolae and their structural protein caveolin 1 (CAV1) have roles in cellular lipid processing and systemic lipid metabolism. Global deletion of CAV1 in mice results in insulin resistance and increases in atherogenic plasma lipids and cholesterol, but protects from diet-induced obesity and atherosclerosis. Despite the fundamental role of the intestinal epithelia in the regulation of dietary lipid processing and metabolism, the contributions of CAV1 to lipid metabolism in this tissue have never been directly investigated. In this study the cellular dynamics of intestinal Cav1 were visualized in zebrafish and the metabolic contributions of CAV1 were determined with mice lacking CAV1 in intestinal epithelial cells (CAV1IEC-KO). Live imaging of Cav1–GFP and fluorescently labeled caveolae cargos shows localization to the basolateral and lateral enterocyte plasma membrane (PM), suggesting Cav1 mediates transport between enterocytes and the submucosa. CAV1IEC-KO mice are protected from the elevation in circulating fasted low-density lipoprotein (LDL) cholesterol associated with a high-fat diet (HFD), but have increased postprandial LDL cholesterol, total free fatty acids (FFAs), palmitoleic acid, and palmitic acid. The increase in circulating FAs in HFD CAV1IEC-KO mice is mirrored by decreased hepatic FAs, suggesting a non-cell-autonomous role for intestinal epithelial cell CAV1 in promoting hepatic FA storage. In conclusion, CAV1 regulates circulating LDL cholesterol and several FA species via the basolateral PM of enterocytes. These results point to intestinal epithelial cell CAV1 as a potential therapeutic target to lower circulating FFAs and LDL cholesterol, as high levels are associated with development of type II diabetes and cardiovascular disease. Summary: Caveolin 1, which forms caveolae, localizes to the basolateral membrane of zebrafish intestinal epithelial cells and regulates circulating murine fatty acid and lipoprotein cholesterol levels.
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Affiliation(s)
- Jessica P Otis
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - Meng-Chieh Shen
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - Vanessa Quinlivan
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA.,Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
| | - Jennifer L Anderson
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA
| | - Steven A Farber
- Carnegie Institution for Science, Department of Embryology, Baltimore, MD 21218, USA .,Johns Hopkins University, Department of Biology, Baltimore, MD 21218, USA
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7
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Design and synthesis of a novel glycosphingolipid derived from polyhydroxy 2-pyrrolidinone and phytoceramide appended by a 1,2,3-triazole linker. Chem Phys Lipids 2016; 194:158-64. [DOI: 10.1016/j.chemphyslip.2015.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 08/01/2015] [Accepted: 08/03/2015] [Indexed: 12/26/2022]
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8
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Cota CD, Davidson B. Mitotic Membrane Turnover Coordinates Differential Induction of the Heart Progenitor Lineage. Dev Cell 2015; 34:505-19. [PMID: 26300448 DOI: 10.1016/j.devcel.2015.07.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 04/14/2015] [Accepted: 07/02/2015] [Indexed: 02/07/2023]
Abstract
In response to microenvironmental cues, embryonic cells form adhesive signaling compartments that influence survival and patterning. Dividing cells detach from the surrounding matrix and initiate extensive membrane remodeling, but the in vivo impact of mitosis on adhesion-dependent signaling remains poorly characterized. We investigate in vivo signaling dynamics using the invertebrate chordate, Ciona intestinalis. In Ciona, matrix adhesion polarizes fibroblast growth factor (FGF)-dependent heart progenitor induction. Here, we show that adhesion inhibits mitotic FGF receptor internalization, leading to receptor enrichment along adherent membranes. Targeted disruption of matrix adhesion promotes uniform FGF receptor internalization and degradation while enhanced adhesion suppresses degradation. Chimeric analysis indicates that integrin β chain-specific impacts on induction are dictated by distinct internalization motifs. We also found that matrix adhesion impacts receptor enrichment through Caveolin-rich membrane domains. These results redefine the relationship between cell division and adhesive signaling, revealing how mitotic membrane turnover orchestrates adhesion-dependent signal polarization.
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Affiliation(s)
- Christina D Cota
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA
| | - Brad Davidson
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA.
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9
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How chemistry supports cell biology: the chemical toolbox at your service. Trends Cell Biol 2014; 24:751-60. [PMID: 25108565 DOI: 10.1016/j.tcb.2014.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/10/2014] [Accepted: 07/10/2014] [Indexed: 01/07/2023]
Abstract
Chemical biology is a young and rapidly developing scientific field. In this field, chemistry is inspired by biology to create various tools to monitor and modulate biochemical and cell biological processes. Chemical contributions such as small-molecule inhibitors and activity-based probes (ABPs) can provide new and unique insights into previously unexplored cellular processes. This review provides an overview of recent breakthroughs in chemical biology that are likely to have a significant impact on cell biology. We also discuss the application of several chemical tools in cell biology research.
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10
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Itokazu Y, Pagano RE, Schroeder AS, O'Grady SM, Limper AH, Marks DL. Reduced GM1 ganglioside in CFTR-deficient human airway cells results in decreased β1-integrin signaling and delayed wound repair. Am J Physiol Cell Physiol 2014; 306:C819-30. [PMID: 24500283 DOI: 10.1152/ajpcell.00168.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Loss of cystic fibrosis transmembrane conductance regulator (CFTR) function reduces chloride secretion and increases sodium uptake, but it is not clear why CFTR mutation also results in progressive lung inflammation and infection. We previously demonstrated that CFTR-silenced airway cells migrate more slowly during wound repair than CFTR-expressing controls. In addition, CFTR-deficient cells and mouse models have been reported to have altered sphingolipid levels. Here, we investigated the hypothesis that reduced migration in CFTR-deficient airway epithelial cells results from altered sphingolipid composition. We used cell lines derived from a human airway epithelial cell line (Calu-3) stably transfected with CFTR short hairpin RNA (CFTR-silenced) or nontargeting short hairpin RNA (controls). Cell migration was measured by electric cell substrate impedance sensing (ECIS). Lipid analyses, addition of exogenous glycosphingolipids, and immunoblotting were performed. We found that levels of the glycosphingolipid, GM1 ganglioside, were ~60% lower in CFTR-silenced cells than in controls. CFTR-silenced cells exhibited reduced levels of activated β1-integrin, phosphorylated tyrosine 576 of focal adhesion kinase (pFAK), and phosphorylation of Crk-associated substrate (pCAS). Addition of GM1 (but not GM3) ganglioside to CFTR-silenced cells restored activated β1-integrin, pFAK, and pCAS to near control levels and partially restored (~40%) cell migration. Our results suggest that decreased GM1 in CFTR-silenced cells depresses β1-integrin signaling, which contributes to the delayed wound repair observed in these cells. These findings have implications for the pathology of cystic fibrosis, where altered sphingolipid levels in airway epithelial cells could result in a diminished capacity for wound repair after injury.
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Affiliation(s)
- Yutaka Itokazu
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic and Foundation, Rochester, Minnesota
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11
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Tight junction regulation through vesicle trafficking: bringing cells together. Biochem Soc Trans 2014; 42:195-200. [DOI: 10.1042/bst20130162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Epithelial layers are integral for many physiological processes and are maintained by intercellular adhesive structures. During disease, these structures can disassemble, leading to breakdown of epithelia. TJs (tight junctions) are one type of intercellular adhesion. Loss of TJs has been linked to the pathogenesis of many diseases. The present review focuses on the role of vesicle trafficking in regulation of TJs, in particular trafficking of the TJ protein occludin. We examine how endocytosis and endosomal recycling modulate occludin localization under steady-state conditions and during stimulated TJ disassembly.
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12
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CLN3 loss disturbs membrane microdomain properties and protein transport in brain endothelial cells. J Neurosci 2014; 33:18065-79. [PMID: 24227717 DOI: 10.1523/jneurosci.0498-13.2013] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Juvenile neuronal ceroid lipofuscinosis (JNCL) is a fatal childhood-onset neurodegenerative disorder caused by mutations in ceroid lipofuscinosis neuronal-3 (CLN3), a hydrophobic transmembrane protein of unresolved function. Previous studies indicate blood-brain barrier (BBB) defects in JNCL, and our earlier report showed prominent Cln3 expression in mouse brain endothelium. Here we find that CLN3 is necessary for normal trafficking of the microdomain-associated proteins caveolin-1, syntaxin-6, and multidrug resistance protein 1 (MDR1) in brain endothelial cells. Correspondingly, CLN3-null cells have reduced caveolae, and impaired caveolae- and MDR1-related functions including endocytosis, drug efflux, and cell volume regulation. We also detected an abnormal blood-brain barrier response to osmotic stress in vivo. Evaluation of the plasma membrane with fluorescent sphingolipid probes suggests microdomain destabilization and enhanced fluidity in CLN3-null cells. In further work we found that application of the glycosphingolipid lactosylceramide to CLN3-deficient cells rescues protein transport and caveolar endocytosis. Last, we show that CLN3 localizes to the trans-Golgi network (TGN) and partitions with buoyant microdomain fractions. We propose that CLN3 facilitates TGN-to-plasma membrane transport of microdomain-associated proteins. Insult to this pathway may underlie BBB dysfunction and contribute to JNCL pathogenesis.
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13
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Singh RD, Schroeder AS, Scheffer L, Holicky EL, Wheatley CL, Marks DL, Pagano RE. Prominin-2 expression increases protrusions, decreases caveolae and inhibits Cdc42 dependent fluid phase endocytosis. Biochem Biophys Res Commun 2013; 434:466-72. [PMID: 23583380 DOI: 10.1016/j.bbrc.2013.03.097] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 03/26/2013] [Indexed: 11/18/2022]
Abstract
BACKGROUND Membrane protrusions play important roles in biological processes such as cell adhesion, wound healing, migration, and sensing of the external environment. Cell protrusions are a subtype of membrane microdomains composed of cholesterol and sphingolipids, and can be disrupted by cholesterol depletion. Prominins are pentaspan membrane proteins that bind cholesterol and localize to plasma membrane (PM) protrusions. Prominin-1 is of great interest as a marker for stem and cancer cells, while Prominin-2 (Prom2) is reportedly restricted to epithelial cells. AIM To characterize the effects of Prom-2 expression on PM microdomain organization. METHODS Prom2-fluorescent protein was transfected in human skin fibroblasts (HSF) and Chinese hamster ovary (CHO) cells for PM raft and endocytic studies. Caveolae at PM were visualized using transmission electron microscopy. Cdc42 activation was measured and caveolin-1 knockdown was performed using siRNAs. RESULTS Prom2 expression in HSF and CHO cells caused extensive Prom2-positive protrusions that co-localized with lipid raft markers. Prom2 expression significantly decreased caveolae at the PM, reduced caveolar endocytosis and increased caveolin-1 phosphorylation. Prom2 expression also inhibited Cdc42-dependent fluid phase endocytosis via decreased Cdc42 activation. Effects on endocytosis were reversed by addition of cholesterol. Knockdown of caveolin-1 by siRNA restored Cdc42 dependent fluid phase endocytosis in Prom2-expressing cells. CONCLUSIONS Prom2 protrusions primarily localize to lipid rafts and recruit cholesterol into protrusions and away from caveolae, leading to increased phosphorylation of caveolin-1, which inhibits Cdc42-dependent endocytosis. This study provides a new insight for the role for prominins in the regulation of PM lipid organization.
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Affiliation(s)
- Raman Deep Singh
- Departments of Medicine, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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14
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Ohmine S, Singh RD, Marks DL, Meyer MA, Pagano RE, Ikeda Y. Viral attachment induces rapid recruitment of an innate immune sensor (TRIM5α) to the plasma membrane. J Innate Immun 2013; 5:414-24. [PMID: 23548691 DOI: 10.1159/000346963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Accepted: 01/07/2013] [Indexed: 11/19/2022] Open
Abstract
TRIM5α (tripartite motif 5α) acts as a pattern recognition receptor specific for the retrovirus capsid lattice and blocks infection by HIV-1 immediately after entry. However, the precise mechanisms underlying this rapid recognition of viral components remain elusive. Here, we analyzed the influence of viral exposure on TRIM5α. Total internal reflection fluorescence microscopy and lipid flotation assays revealed rapid recruitment of a TRIM5α subpopulation to the plasma membrane (PM) upon exposure to vesicular stomatitis virus-G-pseudotyped HIV-1 viral-like particles (VLPs), but not to envelope (Env)-less HIV-1 VLPs. TRIM5α signals were frequently colocalized with those of HIV-1 capsid at the PM. Exposure to HIV-1 Env-pseudotyped HIV-1 vectors also triggered translocation of endogenous TRIM5α to lipid microdomains within human T cells. Similarly, clustering of lipid microdomains by a glycosphingolipid stereoisomer resulted in rapid TRIM5α recruitment to the PM. Of note, recruitment of endogenous rhesus TRIM5α to the PM prior to HIV-1 infection significantly increased the potency of viral restriction. Our data therefore suggest the importance of TRIM5α recruitment to the PM for TRIM5α-mediated innate immune sensing and restriction of retroviral infection.
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Affiliation(s)
- Seiga Ohmine
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA
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15
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Akhtar N, Streuli CH. An integrin-ILK-microtubule network orients cell polarity and lumen formation in glandular epithelium. Nat Cell Biol 2013; 15:17-27. [PMID: 23263281 PMCID: PMC3701152 DOI: 10.1038/ncb2646] [Citation(s) in RCA: 173] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/07/2012] [Indexed: 12/16/2022]
Abstract
The extracellular matrix has a crucial role in determining the spatial orientation of epithelial polarity and the formation of lumens in glandular tissues; however, the underlying mechanisms remain elusive. By using Cre–Lox deletion we show that β1 integrins are required for normal mammary gland morphogenesis and lumen formation, both in vivo and in a three-dimensional primary culture model in which epithelial cells directly contact a basement membrane. Downstream of basement membrane β1 integrins, Rac1 is not involved; however, ILK is needed to polarize microtubule plus ends at the basolateral membrane and disrupting each of these components prevents lumen formation. The integrin–microtubule axis is necessary for the endocytic removal of apical proteins from the basement-membrane–cell interface and for internal Golgi positioning. We propose that this integrin signalling network controls the delivery of apical components to the correct surface and thereby governs the orientation of polarity and development of lumens.
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Affiliation(s)
- Nasreen Akhtar
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M139PT, UK.
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16
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Abstract
There is growing evidence that cell membranes can contain domains with different lipid and protein compositions and with different physical properties. Furthermore, it is increasingly appreciated that sphingolipids play a crucial role in the formation and properties of ordered lipid domains (rafts) in cell membranes. This review describes recent advances in our understanding of ordered membrane domains in both cells and model membranes. In addition, how the structure of sphingolipids influences their ability to participate in the formation of ordered domains, as well as how sphingolipid structure alters ordered domain properties, is described. The diversity of sphingolipid structure is likely to play an important role in modulating the biologically relevant properties of "rafts" in cell membranes.
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17
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Carmona EM, Kottom TJ, Hebrink DM, Moua T, Singh RD, Pagano RE, Limper AH. Glycosphingolipids mediate pneumocystis cell wall β-glucan activation of the IL-23/IL-17 axis in human dendritic cells. Am J Respir Cell Mol Biol 2012; 47:50-9. [PMID: 22343219 PMCID: PMC3402796 DOI: 10.1165/rcmb.2011-0159oc] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Accepted: 02/02/2012] [Indexed: 01/04/2023] Open
Abstract
Pneumocystis species are opportunistic fungal organisms that cause severe pneumonia in immune-compromised hosts, with resultant high morbidity and mortality. Recent work indicates that IL-17 responses are important components of host defense against fungal pathogens. In the present study, we demonstrate that cell-surface β-glucan components of Pneumocystis (PCBG) stimulate human dendritic cells (DCs) to secrete IL-23 and IL-6. These cytokines are well established to stimulate a T helper-17 (Th17) phenotype. Accordingly, we further observe that PCBG-stimulated human DCs interact with lymphocytes to drive the secretion of IL-17 and IL-22, both Th17-produced cytokines. The activation of DCs was shown to involve the dectin-1 receptor with a downstream activation of the Syk kinase and subsequent translocation of both the canonical and noncanonical components of the NF-κB transcription factor family. Finally, we demonstrate that glycosphingolipid-rich microdomains of the plasma membrane participate in the activation of DCs by PCBG through the accumulation of lactosylceramide at the cell surface during stimulation with PCBG. These data strongly support the idea that the β-glucan surface components of Pneumocystis drive the activation of the IL-23/IL-17 axis during this infection, through a glycosphingolipid-initiated mechanism.
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Affiliation(s)
- Eva M. Carmona
- Thoracic Diseases Research Unit and Division of Pulmonary Critical Care and Internal Medicine, Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota
| | - Theodore J. Kottom
- Thoracic Diseases Research Unit and Division of Pulmonary Critical Care and Internal Medicine, Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota
| | - Deanne M. Hebrink
- Thoracic Diseases Research Unit and Division of Pulmonary Critical Care and Internal Medicine, Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota
| | - Teng Moua
- Thoracic Diseases Research Unit and Division of Pulmonary Critical Care and Internal Medicine, Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota
| | - Raman-Deep Singh
- Thoracic Diseases Research Unit and Division of Pulmonary Critical Care and Internal Medicine, Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota
| | - Richard E. Pagano
- Thoracic Diseases Research Unit and Division of Pulmonary Critical Care and Internal Medicine, Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota
| | - Andrew H. Limper
- Thoracic Diseases Research Unit and Division of Pulmonary Critical Care and Internal Medicine, Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota
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18
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Sigismund S, Confalonieri S, Ciliberto A, Polo S, Scita G, Di Fiore PP. Endocytosis and signaling: cell logistics shape the eukaryotic cell plan. Physiol Rev 2012; 92:273-366. [PMID: 22298658 DOI: 10.1152/physrev.00005.2011] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Our understanding of endocytosis has evolved remarkably in little more than a decade. This is the result not only of advances in our knowledge of its molecular and biological workings, but also of a true paradigm shift in our understanding of what really constitutes endocytosis and of its role in homeostasis. Although endocytosis was initially discovered and studied as a relatively simple process to transport molecules across the plasma membrane, it was subsequently found to be inextricably linked with almost all aspects of cellular signaling. This led to the notion that endocytosis is actually the master organizer of cellular signaling, providing the cell with understandable messages that have been resolved in space and time. In essence, endocytosis provides the communications and supply routes (the logistics) of the cell. Although this may seem revolutionary, it is still likely to be only a small part of the entire story. A wealth of new evidence is uncovering the surprisingly pervasive nature of endocytosis in essentially all aspects of cellular regulation. In addition, many newly discovered functions of endocytic proteins are not immediately interpretable within the classical view of endocytosis. A possible framework, to rationalize all this new knowledge, requires us to "upgrade" our vision of endocytosis. By combining the analysis of biochemical, biological, and evolutionary evidence, we propose herein that endocytosis constitutes one of the major enabling conditions that in the history of life permitted the development of a higher level of organization, leading to the actuation of the eukaryotic cell plan.
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Affiliation(s)
- Sara Sigismund
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
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19
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Allosteric modulation of beta1 integrin function induces lung tissue repair. Adv Pharmacol Sci 2012; 2012:768720. [PMID: 22505883 PMCID: PMC3299389 DOI: 10.1155/2012/768720] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 10/21/2011] [Accepted: 10/31/2011] [Indexed: 12/04/2022] Open
Abstract
The cellular cytoskeleton, adhesion receptors, extracellular matrix composition, and their spatial distribution are together fundamental in a cell's balanced mechanical sensing of its environment. We show that, in lung injury, extracellular matrix-integrin interactions are altered and this leads to signalling alteration and mechanical missensing. The missensing, secondary to matrix alteration and cell surface receptor alterations, leads to increased cellular stiffness, injury, and death. We have identified a monoclonal antibody against β1 integrin which caused matrix remodelling and enhancement of cell survival. The antibody acts as an allosteric dual agonist/antagonist modulator of β1 integrin. Intriguingly, this antibody reversed both functional and structural tissue injury in an animal model of degenerative disease in lung.
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20
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Evans SE, Kottom TJ, Pagano RE, Limper AH. Primary alveolar epithelial cell surface membrane microdomain function is required for Pneumocystis β-glucan-induced inflammatory responses. Innate Immun 2012; 18:709-16. [PMID: 22334619 DOI: 10.1177/1753425912436763] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Intense lung inflammation characterizes respiratory failure associated with Pneumocystis pneumonia. Our laboratory has previously demonstrated that alveolar epithelial cells (AECs) elaborate inflammatory cytokines and chemokines in response to the Pneumocystis carinii cell wall constituent β-(1→3)-glucan (PCBG), and that these responses require lactosylceramide, a prominent glycosphingolipid constituent of certain cell membrane microdomains. The relevance of membrane microdomains, also termed plasma membrane lipid rafts, in cell signaling and macromolecule handling has been increasingly recognized in many biologic systems, but their role in P. carinii-induced inflammation is unknown. To investigate the mechanisms of microdomain-dependent P. carinii-induced inflammation, we challenged primary rat AECs with PCBG with or without pre-incubation with inhibitors of microdomain function. Glycosphingolipid and cholesterol rich microdomain inhibition resulted in significant attenuation of P. carinii-induced expression of TNF-α and the rodent C-X-C chemokine MIP-2, as well as their known inflammatory secondary signaling pathways. We have previously shown that protein kinase C (PKC) is activated by PCBG challenge and herein show that PKC localizes to AEC microdomains. We also demonstrate by conventional microscopy, fluorescence microscopy, confocal microscopy and spectrophotofluorimetry that AECs internalize fluorescently-labeled PCBG by microdomain-mediated mechanisms, and that anti-microdomain pretreatments prevent internalization. Taken together, these data suggest an important role for AEC microdomain function in PCBG-induced inflammatory responses. This offers a potential novel target for therapeutics for a condition that continues to exert unacceptable morbidity and mortality among immunocompromised populations.
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Affiliation(s)
- Scott E Evans
- Thoracic Diseases Research Unit and the Division of Pulmonary Critical Care and Internal Medicine, Mayo Clinic and Foundation, MN 55905, USA
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21
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Bidirectional remodeling of β1-integrin adhesions during chemotropic regulation of nerve growth. BMC Biol 2011; 9:82. [PMID: 22126462 PMCID: PMC3283487 DOI: 10.1186/1741-7007-9-82] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 11/30/2011] [Indexed: 12/13/2022] Open
Abstract
Background Chemotropic factors in the extracellular microenvironment guide nerve growth by acting on the growth cone located at the tip of extending axons. Growth cone extension requires the coordination of cytoskeleton-dependent membrane protrusion and dynamic adhesion to the extracellular matrix, yet how chemotropic factors regulate these events remains an outstanding question. We demonstrated previously that the inhibitory factor myelin-associated glycoprotein (MAG) triggers endocytic removal of the adhesion receptor β1-integrin from the growth cone surface membrane to negatively remodel substrate adhesions during chemorepulsion. Here, we tested how a neurotrophin might affect integrin adhesions. Results We report that brain-derived neurotropic factor (BDNF) positively regulates the formation of substrate adhesions in axonal growth cones during stimulated outgrowth and prevents removal of β1-integrin adhesions by MAG. Treatment of Xenopus spinal neurons with BDNF rapidly triggered β1-integrin clustering and induced the dynamic formation of nascent vinculin-containing adhesion complexes in the growth cone periphery. Both the formation of nascent β1-integrin adhesions and the stimulation of axon extension by BDNF required cytoplasmic calcium ion signaling and integrin activation at the cell surface. Exposure to MAG decreased the number of β1-integrin adhesions in the growth cone during inhibition of axon extension. In contrast, the BDNF-induced adhesions were resistant to negative remodeling by MAG, correlating with the ability of BDNF pretreatment to counteract MAG-inhibition of axon extension. Pre-exposure to MAG prevented the BDNF-induced formation of β1-integrin adhesions and blocked the stimulation of axon extension by BDNF. Conclusions Altogether, these findings demonstrate the neurotrophin-dependent formation of integrin-based adhesions in the growth cone and reveal how a positive regulator of substrate adhesions can block the negative remodeling and growth inhibitory effects of MAG. Such bidirectional remodeling may allow the growth cone to rapidly adjust adhesiveness to the extracellular matrix as a general mechanism for governing axon extension. Techniques for manipulating integrin internalization and activation state may be important for overcoming local inhibitory factors after traumatic injury or neurodegenerative disease to enhance regenerative nerve growth.
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22
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Plasmalemmal vesicle associated protein (PV1) modulates SV40 virus infectivity in CV-1 cells. Biochem Biophys Res Commun 2011; 412:220-5. [PMID: 21827737 DOI: 10.1016/j.bbrc.2011.07.063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 07/18/2011] [Indexed: 11/21/2022]
Abstract
Plasmalemmal vesicle associated protein (Plvap/PV1) is a structural protein required for the formation of the stomatal diaphragms of caveolae. Caveolae are plasma membrane invaginations that were implicated in SV40 virus entry in primate cells. Here we show that de novo Plvap/PV1 expression in CV-1 green monkey epithelial cells significantly reduces the ability of SV40 virus to establish productive infection, when cells are incubated with low concentrations of the virus. However, in presence of high viral titers PV1 has no effect on SV40 virus infectivity. Mechanistically, PV1 expression does not reduce the cell surface expression of known SV40 receptors such as GM1 ganglioside and MHC class I proteins. Furthermore, PV1 does not reduce the binding of virus-like particles made by SV40 VP1 protein to the CV-1 cell surface and does not impact their internalization when cells are incubated with either high or low VLP concentrations. These results suggest that PV1 protein is able to block SV40 infectivity at low but not at high viral concentration either by interfering with the infective internalization pathway at the cell surface or at a post internalization step.
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23
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White AB, Galbiati F, Givogri MI, Lopez Rosas A, Qiu X, van Breemen R, Bongarzone ER. Persistence of psychosine in brain lipid rafts is a limiting factor in the therapeutic recovery of a mouse model for Krabbe disease. J Neurosci Res 2010; 89:352-64. [PMID: 21259322 DOI: 10.1002/jnr.22564] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/18/2010] [Accepted: 10/30/2010] [Indexed: 11/10/2022]
Abstract
Sphingolipids are intrinsic components of membrane lipid rafts. The abnormal accumulation of these molecules may introduce architectural and functional changes in these domains, leading to cellular dysfunction. Galactosylsphingosine (psychosine) is a pathogenic lipid raft-associated molecule whose accumulation leads to brain deterioration and irreversible neurological handicap in the incurable leukodystrophy Krabbe disease (KD). The relevance of clearing excessive levels of pathogenic psychosine from lipid rafts in therapy for KD has not been investigated. The work presented here demonstrates that psychosine inhibits raft-mediated endocytosis in neural cells. In addition, although in vitro enzyme reconstitution is sufficient for the reversal of related endocytic defects in affected neural cells, traditional in vivo enzyme therapies in the mouse model of KD appear to be insufficient for complete removal of pathogenic levels of raft-associated psychosine. This work describes a mechanism that may contribute to limiting the in vivo efficacy of traditional therapies for KD.
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Affiliation(s)
- A B White
- Department of Anatomy and Cell Biology, University of Illinois, Chicago, Illinois, USA
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24
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Affiliation(s)
- Michele Bastiani
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland 4072, Australia
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25
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Marchiando AM, Shen L, Graham WV, Weber CR, Schwarz BT, Austin JR, Raleigh DR, Guan Y, Watson AJM, Montrose MH, Turner JR. Caveolin-1-dependent occludin endocytosis is required for TNF-induced tight junction regulation in vivo. ACTA ACUST UNITED AC 2010; 189:111-26. [PMID: 20351069 PMCID: PMC2854371 DOI: 10.1083/jcb.200902153] [Citation(s) in RCA: 348] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although tight junction morphology is not obviously affected by TNF, this proinflammatory cytokine promotes internalization of occludin, resulting in disrupted barrier function within the intestine. Epithelial paracellular barrier function, determined primarily by tight junction permeability, is frequently disrupted in disease. In the intestine, barrier loss can be mediated by tumor necrosis factor (α) (TNF) signaling and epithelial myosin light chain kinase (MLCK) activation. However, TNF induces only limited alteration of tight junction morphology, and the events that couple structural reorganization to barrier regulation have not been defined. We have used in vivo imaging and transgenic mice expressing fluorescent-tagged occludin and ZO-1 fusion proteins to link occludin endocytosis to TNF-induced tight junction regulation. This endocytosis requires caveolin-1 and is essential for structural and functional tight junction regulation. These data demonstrate that MLCK activation triggers caveolin-1–dependent endocytosis of occludin to effect structural and functional tight junction regulation.
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26
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Hamel S, Fantini J, Schweisguth F. Notch ligand activity is modulated by glycosphingolipid membrane composition in Drosophila melanogaster. ACTA ACUST UNITED AC 2010; 188:581-94. [PMID: 20176925 PMCID: PMC2828914 DOI: 10.1083/jcb.200907116] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Endocytosis of the transmembrane ligands Delta (Dl) and Serrate (Ser) is required for the proper activation of Notch receptors. The E3 ubiquitin ligases Mindbomb1 (Mib1) and Neuralized (Neur) regulate the ubiquitination of Dl and Ser and thereby promote both ligand endocytosis and Notch receptor activation. In this study, we identify the alpha1,4-N-acetylgalactosaminyltransferase-1 (alpha4GT1) gene as a gain of function suppressor of Mib1 inhibition. Expression of alpha4GT1 suppressed the signaling and endocytosis defects of Dl and Ser resulting from the inhibition of mib1 and/or neur activity. Genetic and biochemical evidence indicate that alpha4GT1 plays a regulatory but nonessential function in Notch signaling via the synthesis of a specific glycosphingolipid (GSL), N5, produced by alpha4GT1. Furthermore, we show that the extracellular domain of Ser interacts with GSLs in vitro via a conserved GSL-binding motif, raising the possibility that direct GSL-protein interactions modulate the endocytosis of Notch ligands. Together, our data indicate that specific GSLs modulate the signaling activity of Notch ligands.
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Affiliation(s)
- Sophie Hamel
- Institut Pasteur, Centre National de la Recherche Scientifique URA2578, 75724 Paris, Cedex 15, France
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27
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Stimulation of GLUT4 (glucose transporter isoform 4) storage vesicle formation by sphingolipid depletion. Biochem J 2010; 427:143-50. [PMID: 20085539 DOI: 10.1042/bj20091529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Insulin stimulates glucose transport in fat and skeletal muscle cells primarily by inducing the translocation of GLUT4 (glucose transporter isoform 4) to the PM (plasma membrane) from specialized GSVs (GLUT4 storage vesicles). Glycosphingolipids are components of membrane microdomains and are involved in insulin-regulated glucose transport. Cellular glycosphingolipids decrease during adipocyte differentiation and have been suggested to be involved in adipocyte function. In the present study, we investigated the role of glycosphingolipids in regulating GLUT4 translocation. We decreased glycosphingolipids in 3T3-L1 adipocytes using glycosphingolipid synthesis inhibitors and investigated the effects on GLUT4 translocation using immunocytochemistry, preparation of PM sheets, isolation of GSVs and FRAP (fluorescence recovery after photobleaching) of GLUT4-GFP (green fluorescent protein) in intracellular structures. Glycosphingolipids were located in endosomal vesicles in pre-adipocytes and redistributed to the PM with decreased expression at day 2 after initiation of differentiation. In fully differentiated adipocytes, depletion of glycosphingolipids dramatically accelerated insulin-stimulated GLUT4 translocation. Although insulin-induced phosphorylation of IRS (insulin receptor substrate) and Akt remained intact in glycosphingolipid-depleted cells, both in vitro budding of GLUT4 vesicles and FRAP of GLUT4-GFP on GSVs were stimulated. Glycosphingolipid depletion also enhanced the insulin-induced translocation of VAMP2 (vesicle-associated membrane protein 2), but not the transferrin receptor or cellubrevin, indicating that the effect of glycosphingolipids was specific to VAMP2-positive GSVs. Our results strongly suggest that decreasing glycosphingolipid levels promotes the formation of GSVs and, thus, GLUT4 translocation. These studies provide a mechanistic basis for recent studies showing that inhibition of glycosphingolipid synthesis improves glycaemic control and enhances insulin sensitivity in animal models of Type 2 diabetes.
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28
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Cheng ZJ, Singh RD, Holicky EL, Wheatley CL, Marks DL, Pagano RE. Co-regulation of caveolar and Cdc42-dependent fluid phase endocytosis by phosphocaveolin-1. J Biol Chem 2010; 285:15119-15125. [PMID: 20228056 DOI: 10.1074/jbc.m109.069427] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Several clathrin-independent endocytosis mechanisms have been identified that can be distinguished by specific requirements for certain proteins, such as caveolin-1 (Cav1) and the Rho GTPases, RhoA and Cdc42, as well as by specific cargo. Some endocytic pathways may be co-regulated such that disruption of one pathway leads to the up-regulation of another; however, the underlying mechanisms for this are unclear. Cav1 has been reported to function as a guanine nucleotide dissociation inhibitor (GDI), which inhibits Cdc42 activation. We tested the hypothesis that Cav1 can regulate Cdc42-dependent, fluid phase endocytosis. We demonstrate that Cav1 overexpression decreases fluid phase endocytosis, whereas silencing of Cav1 enhances this pathway. Enhancement of Cav1 phosphorylation using a phosphatase inhibitor reduces Cdc42-regulated pinocytosis while stimulating caveolar endocytosis. Fluid phase endocytosis was inhibited by expression of a putative phosphomimetic mutant, Cav1-Y14E, but not by the phospho-deficient mutant, Cav1-Y14F. Overexpression of Cav2, or a Cav1 mutant in which the GDI region was altered to the corresponding sequence in Cav2, did not suppress fluid phase endocytosis. These results suggest that the Cav1 expression level and phosphorylation state regulates fluid phase endocytosis via the interaction between the Cav1 GDI region and Cdc42. These data define a novel molecular mechanism for co-regulation of two distinct clathrin-independent endocytic pathways.
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Affiliation(s)
- Zhi-Jie Cheng
- Departments of Medicine and Biochemistry and Molecular Biology, Thoracic Diseases Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Raman Deep Singh
- Departments of Medicine and Biochemistry and Molecular Biology, Thoracic Diseases Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Eileen L Holicky
- Departments of Medicine and Biochemistry and Molecular Biology, Thoracic Diseases Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Christine L Wheatley
- Departments of Medicine and Biochemistry and Molecular Biology, Thoracic Diseases Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - David L Marks
- Departments of Medicine and Biochemistry and Molecular Biology, Thoracic Diseases Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Richard E Pagano
- Departments of Medicine and Biochemistry and Molecular Biology, Thoracic Diseases Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota 55905.
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29
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Duan Y, Zhang S, Wang B, Yang B, Zhi D. The biological routes of gene delivery mediated by lipid-based non-viral vectors. Expert Opin Drug Deliv 2010; 6:1351-61. [PMID: 19780710 DOI: 10.1517/17425240903287153] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cationic lipid/DNA complexes (lipoplexes) represent an attractive alternative to viral vectors for cell transfection in vitro and in vivo but still suffer from relatively low efficiency. Comprehension of the interactions between vectors and DNA as well as cellular pathways and mechanisms in DNA entry into cells and ultimately nuclei will lead to the design of better adapted non-viral vectors for gene therapy applications. Here, some recent developments in the field on the pathways and mechanisms involved in lipoplex-mediated transfection are discussed. The techniques that are widely used to study the mechanism of gene delivery are also discussed.
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Affiliation(s)
- Yan Duan
- Dalian Nationalities University, College of Life Science, SEAC-ME Key Laboratory of Biotechnology and Bioresources Utilization, Dalian 116600, Liaoning, China
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30
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Singh RD, Marks DL, Holicky EL, Wheatley CL, Kaptzan T, Sato SB, Kobayashi T, Ling K, Pagano RE. Gangliosides and beta1-integrin are required for caveolae and membrane domains. Traffic 2009; 11:348-60. [PMID: 20051050 DOI: 10.1111/j.1600-0854.2009.01022.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Caveolae are plasma membrane domains involved in the uptake of certain pathogens and toxins. Internalization of some cell surface integrins occurs via caveolae suggesting caveolae may play a crucial role in modulating integrin-mediated adhesion and cell migration. Here we demonstrate a critical role for gangliosides (sialo-glycosphingolipids) in regulating caveolar endocytosis in human skin fibroblasts. Pretreatment of cells with endoglycoceramidase (cleaves glycosphingolipids) or sialidase (modifies cell surface gangliosides and glycoproteins) selectively inhibited caveolar endocytosis by >70%, inhibited the formation of plasma membrane domains enriched in sphingolipids and cholesterol ('lipid rafts'), reduced caveolae and caveolin-1 at the plasma membrane by approximately 80%, and blunted activation of beta1-integrin, a protein required for caveolar endocytosis in these cells. These effects could be reversed by a brief incubation with gangliosides (but not with asialo-gangliosides or other sphingolipids) at 10 degrees C, suggesting that sialo-lipids are critical in supporting caveolar endocytosis. Endoglycoceramidase treatment also caused a redistribution of focal adhesion kinase, paxillin, talin, and PIP Kinase Igamma away from focal adhesions. The effects of sialidase or endoglycoceramidase on membrane domains and the distribution of caveolin-1 could be recapitulated by beta1-integrin knockdown. These results suggest that both gangliosides and beta1-integrin are required for maintenance of caveolae and plasma membrane domains.
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Affiliation(s)
- Raman Deep Singh
- Departments of Medicine, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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31
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Puri C. Loss of myosin VI no insert isoform (NoI) induces a defect in clathrin-mediated endocytosis and leads to caveolar endocytosis of transferrin receptor. J Biol Chem 2009; 284:34998-5014. [PMID: 19840950 DOI: 10.1074/jbc.m109.012328] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin VI is a motor protein that moves toward the minus end of actin filaments. It is involved in clathrin-mediated endocytosis and associates with clathrin-coated pits/vesicles at the plasma membrane. In this article the effect of the loss of myosin VI no insert isoform (NoI) on endocytosis in nonpolarized cells was examined. The absence of myosin VI in fibroblasts derived from the Snell's waltzer mouse (myosin VI knock-out) gives rise to defective clathrin-mediated endocytosis with shallow clathrin-coated pits and a strong reduction in the internalization of clathrin-coated vesicles. To compensate for this defect in clathrin-mediated endocytosis, plasma membrane receptors such as the transferrin receptor (TfR) are internalized by a caveola-dependent pathway. Moreover the clathrin adaptor protein, AP-2, necessary for TfR internalization, follows the receptor and relocalizes in caveolae in Snell's waltzer fibroblasts.
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Affiliation(s)
- Claudia Puri
- Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 2XY, United Kingdom.
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Müller G, Jung C, Wied S, Biemer-Daub G. Induced translocation of glycosylphosphatidylinositol-anchored proteins from lipid droplets to adiposomes in rat adipocytes. Br J Pharmacol 2009; 158:749-70. [PMID: 19703169 PMCID: PMC2765595 DOI: 10.1111/j.1476-5381.2009.00360.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 03/06/2009] [Accepted: 03/30/2009] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND AND PURPOSE Adipocytes release membrane vesicles called adiposomes, which harbor the glycosylphosphatidylinositol-anchored proteins (GPI proteins), Gce1 and CD73, after induction with palmitate, H(2)O(2) and the sulphonylurea drug glimepiride. The role of lipid droplets (LD) in trafficking of GPI proteins from detergent-insoluble, glycolipid-enriched, plasma membrane microdomains (DIGs) to adiposomes in rat adipocytes was studied. EXPERIMENTAL APPROACH Redistribution of Gce1 and CD73 was followed by pulse-chase and long-term labelling, western blot analysis and activity determinations with subcellular fractions and cell-free systems exposed to palmitate, H(2)O(2) and glimepiride. KEY RESULTS In response to these signals, Gce1 and CD73 disappeared from DIGs, then transiently appeared in LD and finally were released into adiposomes from small, and, more efficiently, large adipocytes. From DIGs to LD, Gce1 and CD73 were accompanied by cholesterol. Cholesterol depletion from DIGs or LD caused accumulation at DIGs or accelerated loss from LD and release into adiposomes, respectively, of the GPI proteins. Blockade of translocation of Gce1, CD73, caveolin-1 and perilipin-A from DIGs to LD blocked LD biogenesis and long term-accumulation of LD interfered with induced release of the GPI proteins into adiposomes. GPI protein release was up-regulated upon long term-depletion of LD. Adiposomes were released by a DIGs-based cell-free system, but only in presence of LD. CONCLUSIONS GPI proteins are translocated from DIGs to LD prior to their release into adiposomes, which is regulated by cholesterol, LD content and LD biogenesis. This detour may serve to transfer information about the LD content and to control lipolysis/esterification between large and small adipocytes via GPI protein-harbouring adiposomes.
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Affiliation(s)
- G Müller
- Sanofi-Aventis Pharma, R & D, Therapeutic Department Metabolism, Frankfurt am Main, Germany.
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Fantini J, Barrantes FJ. Sphingolipid/cholesterol regulation of neurotransmitter receptor conformation and function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2345-61. [PMID: 19733149 DOI: 10.1016/j.bbamem.2009.08.016] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2009] [Revised: 07/17/2009] [Accepted: 08/28/2009] [Indexed: 10/20/2022]
Abstract
Like all other monomeric or multimeric transmembrane proteins, receptors for neurotransmitters are surrounded by a shell of lipids which form an interfacial boundary between the protein and the bulk membrane. Among these lipids, cholesterol and sphingolipids have attracted much attention because of their well-known propensity to segregate into ordered platform domains commonly referred to as lipid rafts. In this review we present a critical analysis of the molecular mechanisms involved in the interaction of cholesterol/sphingolipids with neurotransmitter receptors, in particular acetylcholine and serotonin receptors, chosen as representative members of ligand-gated ion channels and G protein-coupled receptors. Cholesterol and sphingolipids interact with these receptors through typical binding sites located in both the transmembrane helices and the extracellular loops. By altering the conformation of the receptors ("chaperone-like" effect), these lipids can regulate neurotransmitter binding, signal transducing functions, and, in the case of multimeric receptors, subunit assembly and subsequent receptor trafficking to the cell surface. Several sphingolipids (especially gangliosides) also exhibit low/moderate affinity for neurotransmitters. We suggest that such lipids could facilitate (i) the attachment of neurotransmitters to the post-synaptic membrane and in some cases (ii) their subsequent delivery to specific protein receptors. Overall, various experimental approaches provide converging evidence that the biological functions of neurotransmitters and their receptors are highly dependent upon sphingolipids and cholesterol, which are active partners of synaptic transmission. Several decades of research have been necessary to untangle the skein of a complex network of molecular interactions between neurotransmitters, their receptors, cholesterol and sphingolipids. This sophisticated crosstalk between all four distinctive partners may allow a fine biochemical tuning of synaptic transmission.
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Affiliation(s)
- Jacques Fantini
- Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (CRN2M), University of Aix-Marseille 2 and Aix-Marseille 3, CNRS UMR 6231, INRA USC 2027, Faculté des Sciences de St. Jérôme, Laboratoire des Interactions Moléculaires et Systèmes Membranaires, Marseille, France
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Kim SY, Wang TK, Singh RD, Wheatley CL, Marks DL, Pagano RE. Proteomic identification of proteins translocated to membrane microdomains upon treatment of fibroblasts with the glycosphingolipid, C8-β-D
-lactosylceramide. Proteomics 2009; 9:4321-8. [DOI: 10.1002/pmic.200900077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Marks DL, Bittman R, Pagano RE. Use of Bodipy-labeled sphingolipid and cholesterol analogs to examine membrane microdomains in cells. Histochem Cell Biol 2008; 130:819-32. [PMID: 18820942 PMCID: PMC3922293 DOI: 10.1007/s00418-008-0509-5] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2008] [Indexed: 01/28/2023]
Abstract
Much evidence has accumulated to show that cellular membranes such as the plasma membrane, contain multiple "microdomains" of differing lipid and protein composition and function. These domains are sometimes enriched in cholesterol and sphingolipids and are believed to be important structures for the regulation of many biological and pathological processes. This review focuses on the use of fluorescent (Bodipy) labeled analogs of sphingolipids and cholesterol to study such domains. We discuss the similarities between the behavior of Bodipy-cholesterol and natural cholesterol in artificial bilayers and in cultured cells, and the use of Bodipy-sphingolipid analogs to visualize membrane domains in living cells based on the concentration-dependent monomer-excimer fluorescence properties of the Bodipy-fluorophore. The use of Bodipy-D-erythro-lactosylceramide is highlighted for detection of domains on the plasma membrane and endosome membranes, and the importance of the sphingolipid stereochemistry in modulating domain formation is discussed. Finally, we suggest that Bodipy-sphingolipids may be useful in future studies to examine the relationship between membrane domains at the cell surface and domains enriched in other lipids and proteins on the inner leaflet of the plasma membrane.
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Affiliation(s)
- David L. Marks
- Thoracic Diseases Research Unit, Department of Medicine, Mayo Clinic College of Medicine, Stabile 8, 200 First Street, SW, Rochester, MN 55905-0001, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Stabile 8, 200 First Street, SW, Rochester, MN 55905-0001, USA
| | - Robert Bittman
- Department of Chemistry and Biochemistry, Queens College, The City University of New York, Flushing, NY 11367, USA
| | - Richard E. Pagano
- Thoracic Diseases Research Unit, Department of Medicine, Mayo Clinic College of Medicine, Stabile 8, 200 First Street, SW, Rochester, MN 55905-0001, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Stabile 8, 200 First Street, SW, Rochester, MN 55905-0001, USA
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Abstract
Throughout the biological world, a 30 A hydrophobic film typically delimits the environments that serve as the margin between life and death for individual cells. Biochemical and biophysical findings have provided a detailed model of the composition and structure of membranes, which includes levels of dynamic organization both across the lipid bilayer (lipid asymmetry) and in the lateral dimension (lipid domains) of membranes. How do cells apply anabolic and catabolic enzymes, translocases and transporters, plus the intrinsic physical phase behaviour of lipids and their interactions with membrane proteins, to create the unique compositions and multiple functionalities of their individual membranes?
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37
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Jansen M, Pietiaïnen VM, Pölönen H, Rasilainen L, Koivusalo M, Ruotsalainen U, Jokitalo E, Ikonen E. Cholesterol substitution increases the structural heterogeneity of caveolae. J Biol Chem 2008; 283:14610-8. [PMID: 18353778 DOI: 10.1074/jbc.m710355200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Caveolin-1 binds cholesterol and caveola formation involves caveolin-1 oligomerization and cholesterol association. The role of cholesterol in caveolae has so far been addressed by methods that compromise membrane integrity and abolish caveolar invaginations. To study the importance of sterol specificity for the structure and function of caveolae, we replaced cholesterol in mammalian cells with its immediate precursor desmosterol by inhibiting 24-dehydrocholesterol reductase. Desmosterol could substitute for cholesterol in maintaining cell growth, membrane integrity, and preserving caveolar invaginations. However, in desmosterol cells the affinity of caveolin-1 for sterol and the stability of caveolin oligomers were decreased. Moreover, caveolar invaginations became more heterogeneous in dimensions and in the number of caveolin-1 molecules per caveola. Despite the altered caveolar structure, caveolar ligand uptake was only moderately inhibited. We found that in desmosterol cells, Src kinase phosphorylated Cav1 at Tyr(14) more avidly than in cholesterol cells. Taken the role of Cav1 Tyr(14) phosphorylation in caveolar endocytosis, this may help to preserve caveolar uptake in desmosterol cells. We conclude that a sterol C24 double bond interferes with caveolin-sterol interaction and perturbs caveolar morphology but facilitates Cav1 Src phosphorylation and allows caveolar endocytosis. More generally, substitution of cholesterol by a structurally closely related sterol provides a method to selectively modify membrane protein-sterol affinity, structure and function of cholesterol-dependent domains without compromising membrane integrity.
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Affiliation(s)
- Maurice Jansen
- Institute of Biomedicine/Anatomy, University of Helsinki, Helsinki, Finland
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The Yin and Yang of lactosylceramide metabolism: Implications in cell function. Biochim Biophys Acta Gen Subj 2008; 1780:370-82. [DOI: 10.1016/j.bbagen.2007.08.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Accepted: 08/13/2007] [Indexed: 11/18/2022]
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39
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Kloepper J, Hendrix S, Bodó E, Tiede S, Humphries M, Philpott M, Fässler R, Paus R. Functional role of β1 integrin-mediated signalling in the human hair follicle. Exp Cell Res 2008; 314:498-508. [DOI: 10.1016/j.yexcr.2007.10.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 10/02/2007] [Accepted: 10/23/2007] [Indexed: 12/17/2022]
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40
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Abstract
There are numerous ways that endocytic cargo molecules may be internalized from the surface of eukaryotic cells. In addition to the classical clathrin-dependent mechanism of endocytosis, several pathways that do not use a clathrin coat are emerging. These pathways transport a diverse array of cargoes and are sometimes hijacked by bacteria and viruses to gain access to the host cell. Here, we review our current understanding of various clathrin-independent mechanisms of endocytosis and propose a classification scheme to help organize the data in this complex and evolving field.
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Affiliation(s)
- Satyajit Mayor
- National Centre for Biological Sciences, UAS-GKVK Campus, Bangalore 560065, India.
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41
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Echarri A, Muriel O, Del Pozo MA. Intracellular trafficking of raft/caveolae domains: insights from integrin signaling. Semin Cell Dev Biol 2007; 18:627-37. [PMID: 17904396 DOI: 10.1016/j.semcdb.2007.08.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 08/10/2007] [Accepted: 08/16/2007] [Indexed: 10/22/2022]
Abstract
Cells have a complex system for delivering and compartmentalizing proteins and lipids in order to achieve spatio-temporal coordination of signaling. Rafts/caveolae are plasma membrane microdomains that regulate signaling pathways and processes such as cell migration, polarization and proliferation. Regulation of raft/caveolae trafficking involves multiple steps regulated by different proteins to ensure coordination of signaling cascades. The best studied raft-mediated endocytic route is controlled by caveolins. Recent data suggest integrin-mediated cell adhesion is a key regulator of caveolar endocytosis. In this review we examine the regulation of caveolar trafficking and the interplay between integrins, cell adhesion and caveolae internalization.
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Affiliation(s)
- Asier Echarri
- Integrin Signaling Laboratory, Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares, Melchor Fernández Almagro, 3, 28029 Madrid, Spain
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