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Castello-Serrano I, Heberle FA, Diaz-Rohrer B, Ippolito R, Shurer CR, Lujan P, Campelo F, Levental KR, Levental I. Partitioning to ordered membrane domains regulates the kinetics of secretory traffic. eLife 2024; 12:RP89306. [PMID: 38837189 PMCID: PMC11152573 DOI: 10.7554/elife.89306] [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] [Indexed: 06/06/2024] Open
Abstract
The organelles of eukaryotic cells maintain distinct protein and lipid compositions required for their specific functions. The mechanisms by which many of these components are sorted to their specific locations remain unknown. While some motifs mediating subcellular protein localization have been identified, many membrane proteins and most membrane lipids lack known sorting determinants. A putative mechanism for sorting of membrane components is based on membrane domains known as lipid rafts, which are laterally segregated nanoscopic assemblies of specific lipids and proteins. To assess the role of such domains in the secretory pathway, we applied a robust tool for synchronized secretory protein traffic (RUSH, Retention Using Selective Hooks) to protein constructs with defined affinity for raft phases. These constructs consist solely of single-pass transmembrane domains (TMDs) and, lacking other sorting determinants, constitute probes for membrane domain-mediated trafficking. We find that while raft affinity can be sufficient for steady-state PM localization, it is not sufficient for rapid exit from the endoplasmic reticulum (ER), which is instead mediated by a short cytosolic peptide motif. In contrast, we find that Golgi exit kinetics are highly dependent on raft affinity, with raft preferring probes exiting the Golgi ~2.5-fold faster than probes with minimal raft affinity. We rationalize these observations with a kinetic model of secretory trafficking, wherein Golgi export can be facilitated by protein association with raft domains. These observations support a role for raft-like membrane domains in the secretory pathway and establish an experimental paradigm for dissecting its underlying machinery.
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Affiliation(s)
- Ivan Castello-Serrano
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of VirginiaCharlottesvilleUnited States
| | | | | | - Rossana Ippolito
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of VirginiaCharlottesvilleUnited States
| | - Carolyn R Shurer
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of VirginiaCharlottesvilleUnited States
| | - Pablo Lujan
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and TechnologyBarcelonaSpain
| | - Felix Campelo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and TechnologyBarcelonaSpain
| | - Kandice R Levental
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of VirginiaCharlottesvilleUnited States
| | - Ilya Levental
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of VirginiaCharlottesvilleUnited States
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Castello-Serrano I, Heberle FA, Diaz-Rohrer B, Ippolito R, Shurer CR, Lujan P, Campelo F, Levental KR, Levental I. Partitioning to ordered membrane domains regulates the kinetics of secretory traffic. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.18.537395. [PMID: 37131599 PMCID: PMC10153169 DOI: 10.1101/2023.04.18.537395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The organelles of eukaryotic cells maintain distinct protein and lipid compositions required for their specific functions. The mechanisms by which many of these components are sorted to their specific locations remain unknown. While some motifs mediating subcellular protein localization have been identified, many membrane proteins and most membrane lipids lack known sorting determinants. A putative mechanism for sorting of membrane components is based on membrane domains known as lipid rafts, which are laterally segregated nanoscopic assemblies of specific lipids and proteins. To assess the role of such domains in the secretory pathway, we applied a robust tool for synchronized secretory protein traffic (RUSH, Retention Using Selective Hooks) to protein constructs with defined affinity for raft phases. These constructs consist solely of single-pass transmembrane domains (TMDs) and, lacking other sorting determinants, constitute probes for membrane domain-mediated trafficking. We find that while raft affinity can be sufficient for steady-state PM localization, it is not sufficient for rapid exit from the endoplasmic reticulum (ER), which is instead mediated by a short cytosolic peptide motif. In contrast, we find that Golgi exit kinetics are highly dependent on raft affinity, with raft preferring probes exiting Golgi ~2.5-fold faster than probes with minimal raft affinity. We rationalize these observations with a kinetic model of secretory trafficking, wherein Golgi export can be facilitated by protein association with raft domains. These observations support a role for raft-like membrane domains in the secretory pathway and establish an experimental paradigm for dissecting its underlying machinery.
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3
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Approach to map nanotopography of cell surface receptors. Commun Biol 2022; 5:218. [PMID: 35264712 PMCID: PMC8907216 DOI: 10.1038/s42003-022-03152-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/09/2022] [Indexed: 12/18/2022] Open
Abstract
Cells communicate with their environment via surface receptors, but nanoscopic receptor organization with respect to complex cell surface morphology remains unclear. This is mainly due to a lack of accessible, robust and high-resolution methods. Here, we present an approach for mapping the topography of receptors at the cell surface with nanometer precision. The method involves coating glass coverslips with glycine, which preserves the fine membrane morphology while allowing immobilized cells to be positioned close to the optical surface. We developed an advanced and simplified algorithm for the analysis of single-molecule localization data acquired in a biplane detection scheme. These advancements enable direct and quantitative mapping of protein distribution on ruffled plasma membranes with near isotropic 3D nanometer resolution. As demonstrated successfully for CD4 and CD45 receptors, the described workflow is a straightforward quantitative technique to study molecules and their interactions at the complex surface nanomorphology of differentiated metazoan cells. A super-resolution localisation-based method is shown to map receptor topography in immune cells, which allows quantitative study of molecules and their interactions at the complex surface nanomorphology of cells.
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4
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Curson JE, Luo L, Liu L, Burgess BJ, Bokil NJ, Wall AA, Brdicka T, Kapetanovic R, Stow JL, Sweet MJ. An alternative downstream translation start site in the non-TIR adaptor Scimp enables selective amplification of CpG DNA responses in mouse macrophages. Immunol Cell Biol 2022; 100:267-284. [PMID: 35201640 PMCID: PMC9544816 DOI: 10.1111/imcb.12540] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 02/17/2022] [Accepted: 02/22/2022] [Indexed: 01/01/2023]
Abstract
Toll-like receptor (TLR) signaling relies on Toll/interleukin-1 receptor homology (TIR) domain-containing adaptor proteins that recruit downstream signaling molecules to generate tailored immune responses. In addition, the palmitoylated transmembrane adaptor protein family member Scimp acts as a non-TIR-containing adaptor protein in macrophages, scaffolding the Src family kinase Lyn to enable TLR phosphorylation and proinflammatory signaling responses. Here we report the existence of a smaller, naturally occurring translational variant of Scimp (Scimp TV1), which is generated through leaky scanning and translation at a downstream methionine. Scimp TV1 also scaffolds Lyn, but in contrast to full-length Scimp, it is basally rather than lipopolysaccharide (LPS)-inducibly phosphorylated. Macrophages from mice that selectively express Scimp TV1, but not full-length Scimp, have impaired sustained LPS-inducible cytokine responses. Furthermore, in granulocyte macrophage colony-stimulating factor-derived myeloid cells that express high levels of Scimp, selective overexpression of Scimp TV1 enhances CpG DNA-inducible cytokine production. Unlike full-length Scimp that localizes to the cell surface and filopodia, Scimp TV1 accumulates in intracellular compartments, particularly the Golgi. Moreover, this variant of Scimp is not inducibly phosphorylated in response to CpG DNA, suggesting that it may act via an indirect mechanism to enhance TLR9 responses. Our findings thus reveal the use of alternative translation start sites as a previously unrecognized mechanism for diversifying TLR responses in the innate immune system.
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Affiliation(s)
- James Eb Curson
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Lin Luo
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Liping Liu
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Belinda J Burgess
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Nilesh J Bokil
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Adam A Wall
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Tomas Brdicka
- Laboratory of Leukocyte Signaling, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ronan Kapetanovic
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia.,Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Jennifer L Stow
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
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5
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Glatzová D, Mavila H, Saija MC, Chum T, Cwiklik L, Brdička T, Cebecauer M. The role of prolines and glycine in the transmembrane domain of LAT. FEBS J 2021; 288:4039-4052. [PMID: 33458942 DOI: 10.1111/febs.15713] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/15/2020] [Accepted: 01/13/2021] [Indexed: 12/30/2022]
Abstract
Linker for activation in T cells (LAT) is a critical regulator of T-cell development and function. It organises signalling events at the plasma membrane. However, the mechanism, which controls LAT localisation at the plasma membrane, is not fully understood. Here, we studied the impact of helix-breaking amino acids, two prolines and one glycine, in the transmembrane segment on localisation and function of LAT. Using in silico analysis, confocal and super-resolution imaging and flow cytometry, we demonstrate that central proline residue destabilises transmembrane helix by inducing a kink. The helical structure and dynamics are further regulated by glycine and another proline residue in the luminal part of LAT transmembrane domain. Replacement of these residues with aliphatic amino acids reduces LAT dependence on palmitoylation for sorting to the plasma membrane. However, surface expression of these mutants is not sufficient to recover function of nonpalmitoylated LAT in stimulated T cells. These data indicate that geometry and dynamics of LAT transmembrane segment regulate its localisation and function in immune cells.
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Affiliation(s)
- Daniela Glatzová
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic.,Laboratory of Leukocyte Signaling, Institute of Molecule Genetics, Czech Academy of Sciences, Prague, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Harsha Mavila
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Maria Chiara Saija
- Department of Computational Chemistry, J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Chum
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Lukasz Cwiklik
- Department of Computational Chemistry, J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Brdička
- Laboratory of Leukocyte Signaling, Institute of Molecule Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Marek Cebecauer
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
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6
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Abdulganiyyu IA, Sani MA, Separovic F, Marco H, Jackson GE. Phote-HrTH (Phormia terraenovae Hypertrehalosaemic Hormone), the Metabolic Hormone of the Fruit Fly: Solution Structure and Receptor Binding Model. Aust J Chem 2020. [DOI: 10.1071/ch19461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Fruit flies are a widely distributed pest insect that pose a significant threat to food security. Flight is essential for the dispersal of the adult flies to find new food sources and ideal breeding spots. The supply of metabolic fuel to power the flight muscles of insects is regulated by adipokinetic hormones (AKHs). The fruit fly, Drosophila melanogaster, has the same AKH that is present in the blowfly, Phormia terraenovae; this AKH has the code-name Phote-HrTH. Binding of the AKH to the extra-cellular binding site of a G protein-coupled receptor causes its activation. In this paper, the structure of Phote-HrTH in sodium dodecyl sulfate (SDS) micelle solution was determined using NMR restrained molecular dynamics. The peptide was found to bind to the micelle and be fairly rigid, with an S2 order parameter of 0.96. The translated protein sequence of the AKH receptor from the fruit fly, D. melanogaster, Drome-AKHR, was used to construct two models of the receptor. It is proposed that these two models represent the active and inactive state of the receptor. The model based on the crystal structure of the β-2 adrenergic receptor was found to bind Phote-HrTH with a binding constant of −102kJmol−1, while the other model, based on the crystal structure of rhodopsin, did not bind the peptide. Under molecular dynamic simulation, in a palmitoyloleoylphosphatidylcholine (POPC) membrane, the receptor complex changed from an inactive to an active state. The identification and characterisation of the ligand binding site of Drome-AKHR provide novel information of ligand–receptor interaction, which could lead to the development of species-specific control substances to use discriminately against the fruit fly.
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7
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Saveanu L, Zucchetti AE, Evnouchidou I, Ardouin L, Hivroz C. Is there a place and role for endocyticTCRsignaling? Immunol Rev 2019; 291:57-74. [DOI: 10.1111/imr.12764] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/02/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Loredana Saveanu
- National French Institute of Health and Medical Research (INSERM) 1149 Center of Research on Inflammation Paris France
- National French Center of Scientific Research (CNRS) ERL8252 Paris France
- Laboratory of Inflamex Excellency Faculty of Medicine Xavier Bichat Site Paris France
- Paris Diderot UniversitySorbonne Paris Cité Paris France
| | - Andres E. Zucchetti
- Institut Curie PSL Research UniversityINSERMU932 “Integrative analysis of T cell activation” team Paris France
| | - Irini Evnouchidou
- National French Institute of Health and Medical Research (INSERM) 1149 Center of Research on Inflammation Paris France
- National French Center of Scientific Research (CNRS) ERL8252 Paris France
- Laboratory of Inflamex Excellency Faculty of Medicine Xavier Bichat Site Paris France
- Paris Diderot UniversitySorbonne Paris Cité Paris France
- Inovarion Paris France
| | - Laurence Ardouin
- Institut Curie PSL Research UniversityINSERMU932 “Integrative analysis of T cell activation” team Paris France
| | - Claire Hivroz
- Institut Curie PSL Research UniversityINSERMU932 “Integrative analysis of T cell activation” team Paris France
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8
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Adámková L, Kvíčalová Z, Rozbeský D, Kukačka Z, Adámek D, Cebecauer M, Novák P. Oligomeric Architecture of Mouse Activating Nkrp1 Receptors on Living Cells. Int J Mol Sci 2019; 20:ijms20081884. [PMID: 30995786 PMCID: PMC6515139 DOI: 10.3390/ijms20081884] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/04/2019] [Accepted: 04/10/2019] [Indexed: 12/03/2022] Open
Abstract
Mouse activating Nkrp1 proteins are commonly described as type II transmembrane receptors with disulfide-linked homodimeric structure. Their function and the manner in which Nkrp1 proteins of mouse strain (C57BL/6) oligomerize are still poorly understood. To assess the oligomerization state of Nkrp1 proteins, mouse activating EGFP-Nkrp1s were expressed in mammalian lymphoid cells and their oligomerization evaluated by Förster resonance energy transfer (FRET). Alternatively, Nkrp1s oligomers were detected by Western blotting to specify the ratio between monomeric and dimeric forms. We also performed structural characterization of recombinant ectodomains of activating Nkrp1 receptors. Nkrp1 isoforms c1, c2 and f were expressed prevalently as homodimers, whereas the Nkrp1a displays larger proportion of monomers on the cell surface. Cysteine-to-serine mutants revealed the importance of all stalk cysteines for protein dimerization in living cells with a major influence of cysteine at position 74 in two Nkrp1 protein isoforms. Our results represent a new insight into the oligomerization of Nkrp1 receptors on lymphoid cells, which will help to determine their function.
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Affiliation(s)
- Ljubina Adámková
- Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, The Czech Academy of Sciences, Vídeňská 1083, 14220 Prague 4, Czech Republic.
| | - Zuzana Kvíčalová
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 2155/3, 18223 Prague 8, Czech Republic.
| | - Daniel Rozbeský
- Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, The Czech Academy of Sciences, Vídeňská 1083, 14220 Prague 4, Czech Republic.
| | - Zdeněk Kukačka
- Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, The Czech Academy of Sciences, Vídeňská 1083, 14220 Prague 4, Czech Republic.
| | - David Adámek
- Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, The Czech Academy of Sciences, Vídeňská 1083, 14220 Prague 4, Czech Republic.
| | - Marek Cebecauer
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 2155/3, 18223 Prague 8, Czech Republic.
| | - Petr Novák
- Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, The Czech Academy of Sciences, Vídeňská 1083, 14220 Prague 4, Czech Republic.
- Department of Biochemistry, Charles University, Hlavova 8, 12843 Prague 2, Czech Republic.
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9
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Sobocińska J, Roszczenko-Jasińska P, Ciesielska A, Kwiatkowska K. Protein Palmitoylation and Its Role in Bacterial and Viral Infections. Front Immunol 2018; 8:2003. [PMID: 29403483 PMCID: PMC5780409 DOI: 10.3389/fimmu.2017.02003] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 12/26/2017] [Indexed: 12/11/2022] Open
Abstract
S-palmitoylation is a reversible, enzymatic posttranslational modification of proteins in which palmitoyl chain is attached to a cysteine residue via a thioester linkage. S-palmitoylation determines the functioning of proteins by affecting their association with membranes, compartmentalization in membrane domains, trafficking, and stability. In this review, we focus on S-palmitoylation of proteins, which are crucial for the interactions of pathogenic bacteria and viruses with the host. We discuss the role of palmitoylated proteins in the invasion of host cells by bacteria and viruses, and those involved in the host responses to the infection. We highlight recent data on protein S-palmitoylation in pathogens and their hosts obtained owing to the development of methods based on click chemistry and acyl-biotin exchange allowing proteomic analysis of protein lipidation. The role of the palmitoyl moiety present in bacterial lipopolysaccharide and lipoproteins, contributing to infectivity and affecting recognition of bacteria by innate immune receptors, is also discussed.
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Affiliation(s)
- Justyna Sobocińska
- Laboratory of Molecular Membrane Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Paula Roszczenko-Jasińska
- Laboratory of Molecular Membrane Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Anna Ciesielska
- Laboratory of Molecular Membrane Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
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10
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Murrell-Lagnado RD. Regulation of P2X Purinergic Receptor Signaling by Cholesterol. CURRENT TOPICS IN MEMBRANES 2017; 80:211-232. [PMID: 28863817 DOI: 10.1016/bs.ctm.2017.05.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
P2X receptors are cation-selective channels that are activated by the binding of extracellular ATP. They have a high permeability to Ca2+, Na+, and K+ and are expressed widely throughout the nervous, immune, cardiovascular, skeletal, gastrointestinal, respiratory, and endocrine systems. Seven mammalian subtypes of P2X receptor subunits have been identified, P2X1-7, and those that function as homotrimeric receptors (P2X1, 2, 3, 4, and 7) are targeted to lipid rafts, although they show limited resistance to solubilization by Triton X-100. Recent crystal structures of P2X3 and P2X4 receptors have provided considerable high-resolution information about the architecture of this family of receptors and yet the molecular details of how they are regulated by cholesterol are unknown. Currents mediated by the P2X1-4 receptors are either inhibited or relatively insensitive to cholesterol depletion, but there is no clear evidence to support the direct binding of cholesterol to these receptors. In contrast, the activity of the low-affinity, proinflammatory P2X7 receptor is potentiated by cholesterol depletion and regions within the proximal C-terminus play an important role in coupling changes in cholesterol to the gating of the pore. Based upon our understanding of the lipid signaling events that are triggered downstream of P2X7 receptor activation, a change in the levels of cholesterol may contribute to the sensitization of receptor currents and the dilation of the pore that occurs following prolonged, high-level stimulation. This chapter focuses on the regulation of P2X7 receptor signaling by cholesterol and our current understanding of the mechanisms that underlie this.
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Affiliation(s)
- Ruth D Murrell-Lagnado
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom.
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11
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Gaibelet G, Tercé F, Allart S, Lebrun C, Collet X, Jamin N, Orlowski S. Fluorescent probes for detecting cholesterol-rich ordered membrane microdomains: entangled relationships between structural analogies in the membrane and functional homologies in the cell. AIMS BIOPHYSICS 2017. [DOI: 10.3934/biophy.2017.1.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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12
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Roberts BJ, Svoboda RA, Overmiller AM, Lewis JD, Kowalczyk AP, Mahoney MG, Johnson KR, Wahl JK. Palmitoylation of Desmoglein 2 Is a Regulator of Assembly Dynamics and Protein Turnover. J Biol Chem 2016; 291:24857-24865. [PMID: 27703000 DOI: 10.1074/jbc.m116.739458] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 09/08/2016] [Indexed: 01/09/2023] Open
Abstract
Desmosomes are prominent adhesive junctions present between many epithelial cells as well as cardiomyocytes. The mechanisms controlling desmosome assembly and remodeling in epithelial and cardiac tissue are poorly understood. We recently identified protein palmitoylation as a mechanism regulating desmosome dynamics. In this study, we have focused on the palmitoylation of the desmosomal cadherin desmoglein-2 (Dsg2) and characterized the role that palmitoylation of Dsg2 plays in its localization and stability in cultured cells. We identified two cysteine residues in the juxtamembrane (intracellular anchor) domain of Dsg2 that, when mutated, eliminate its palmitoylation. These cysteine residues are conserved in all four desmoglein family members. Although mutant Dsg2 localizes to endogenous desmosomes, there is a significant delay in its incorporation into junctions, and the mutant is also present in a cytoplasmic pool. Triton X-100 solubility assays demonstrate that mutant Dsg2 is more soluble than wild-type protein. Interestingly, trafficking of the mutant Dsg2 to the cell surface was delayed, and a pool of the non-palmitoylated Dsg2 co-localized with lysosomal markers. Taken together, these data suggest that palmitoylation of Dsg2 regulates protein transport to the plasma membrane. Modulation of the palmitoylation status of desmosomal cadherins can affect desmosome dynamics.
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Affiliation(s)
- Brett J Roberts
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583
| | - Robert A Svoboda
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583
| | - Andrew M Overmiller
- the Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Joshua D Lewis
- the Departments of Cell Biology and Dermatology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Andrew P Kowalczyk
- the Departments of Cell Biology and Dermatology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - My G Mahoney
- the Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Keith R Johnson
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583.,the Eppley Institute for Research in Cancer and Allied Diseases, Omaha, Nebraska 68198
| | - James K Wahl
- From the Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583,
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13
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Bernardino de la Serna J, Schütz GJ, Eggeling C, Cebecauer M. There Is No Simple Model of the Plasma Membrane Organization. Front Cell Dev Biol 2016; 4:106. [PMID: 27747212 PMCID: PMC5040727 DOI: 10.3389/fcell.2016.00106] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/14/2016] [Indexed: 12/29/2022] Open
Abstract
Ever since technologies enabled the characterization of eukaryotic plasma membranes, heterogeneities in the distributions of its constituents were observed. Over the years this led to the proposal of various models describing the plasma membrane organization such as lipid shells, picket-and-fences, lipid rafts, or protein islands, as addressed in numerous publications and reviews. Instead of emphasizing on one model we in this review give a brief overview over current models and highlight how current experimental work in one or the other way do not support the existence of a single overarching model. Instead, we highlight the vast variety of membrane properties and components, their influences and impacts. We believe that highlighting such controversial discoveries will stimulate unbiased research on plasma membrane organization and functionality, leading to a better understanding of this essential cellular structure.
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Affiliation(s)
- Jorge Bernardino de la Serna
- Science and Technology Facilities Council, Rutherford Appleton Laboratory, Central Laser Facility, Research Complex at Harwell Harwell, UK
| | - Gerhard J Schütz
- Institute of Applied Physics, Technische Universität Wien Wien, Austria
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford Headley Way, UK
| | - Marek Cebecauer
- Department of Biophysical Chemistry, J.Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences Prague, Czech Republic
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14
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Halova I, Draber P. Tetraspanins and Transmembrane Adaptor Proteins As Plasma Membrane Organizers-Mast Cell Case. Front Cell Dev Biol 2016; 4:43. [PMID: 27243007 PMCID: PMC4861716 DOI: 10.3389/fcell.2016.00043] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/25/2016] [Indexed: 12/16/2022] Open
Abstract
The plasma membrane contains diverse and specialized membrane domains, which include tetraspanin-enriched domains (TEMs) and transmembrane adaptor protein (TRAP)-enriched domains. Recent biophysical, microscopic, and functional studies indicated that TEMs and TRAP-enriched domains are involved in compartmentalization of physicochemical events of such important processes as immunoreceptor signal transduction and chemotaxis. Moreover, there is evidence of a cross-talk between TEMs and TRAP-enriched domains. In this review we discuss the presence and function of such domains and their crosstalk using mast cells as a model. The combined data based on analysis of selected mast cell-expressed tetraspanins [cluster of differentiation (CD)9, CD53, CD63, CD81, CD151)] or TRAPs [linker for activation of T cells (LAT), non-T cell activation linker (NTAL), and phosphoprotein associated with glycosphingolipid-enriched membrane microdomains (PAG)] using knockout mice or specific antibodies point to a diversity within these two families and bring evidence of the important roles of these molecules in signaling events. An example of this diversity is physical separation of two TRAPs, LAT and NTAL, which are in many aspects similar but show plasma membrane location in different microdomains in both non-activated and activated cells. Although our understanding of TEMs and TRAP-enriched domains is far from complete, pharmaceutical applications of the knowledge about these domains are under way.
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Affiliation(s)
- Ivana Halova
- Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic Prague, Czech Republic
| | - Petr Draber
- Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic Prague, Czech Republic
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Borgese N. Getting membrane proteins on and off the shuttle bus between the endoplasmic reticulum and the Golgi complex. J Cell Sci 2016; 129:1537-45. [PMID: 27029344 DOI: 10.1242/jcs.183335] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Secretory proteins exit the endoplasmic reticulum (ER) in coat protein complex II (COPII)-coated vesicles and then progress through the Golgi complex before delivery to their final destination. Soluble cargo can be recruited to ER exit sites by signal-mediated processes (cargo capture) or by bulk flow. For membrane proteins, a third mechanism, based on the interaction of their transmembrane domain (TMD) with lipid microdomains, must also be considered. In this Commentary, I review evidence in favor of the idea that partitioning of TMDs into bilayer domains that are endowed with distinct physico-chemical properties plays a pivotal role in the transport of membrane proteins within the early secretory pathway. The combination of such self-organizational phenomena with canonical intermolecular interactions is most likely to control the release of membrane proteins from the ER into the secretory pathway.
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Affiliation(s)
- Nica Borgese
- CNR Institute of Neuroscience, Milan 20129, Italy
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