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Eschrig S, Schäffer M, Shu LJ, Illig T, Eibel S, Fernandez A, Ranf S. LORE receptor homomerization is required for 3-hydroxydecanoic acid-induced immune signaling and determines the natural variation of immunosensitivity within the Arabidopsis genus. THE NEW PHYTOLOGIST 2024; 242:2163-2179. [PMID: 38532564 DOI: 10.1111/nph.19715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 03/07/2024] [Indexed: 03/28/2024]
Abstract
The S-domain-type receptor-like kinase (SD-RLK) LIPOOLIGOSACCHARIDE-SPECIFIC REDUCED ELICITATION (LORE) from Arabidopsis thaliana is a pattern recognition receptor that senses medium-chain 3-hydroxy fatty acids, such as 3-hydroxydecanoic acid (3-OH-C10:0), to activate pattern-triggered immunity. Here, we show that LORE homomerization is required to activate 3-OH-C10:0-induced immune signaling. Fluorescence lifetime imaging in Nicotiana benthamiana demonstrates that AtLORE homomerizes via the extracellular and transmembrane domains. Co-expression of AtLORE truncations lacking the intracellular domain exerts a dominant negative effect on AtLORE signaling in both N. benthamiana and A. thaliana, highlighting that homomerization is essential for signaling. Screening for 3-OH-C10:0-induced reactive oxygen species production revealed natural variation within the Arabidopsis genus. Arabidopsis lyrata and Arabidopsis halleri do not respond to 3-OH-C10:0, although both possess a putative LORE ortholog. Both LORE orthologs have defective extracellular domains that bind 3-OH-C10:0 to a similar level as AtLORE, but lack the ability to homomerize. Thus, ligand binding is independent of LORE homomerization. Analysis of AtLORE and AlyrLORE chimera suggests that the loss of AlyrLORE homomerization is caused by several amino acid polymorphisms across the extracellular domain. Our findings shed light on the activation mechanism of LORE and the loss of 3-OH-C10:0 perception within the Arabidopsis genus.
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Affiliation(s)
- Sabine Eschrig
- TUM School of Life Sciences, Chair of Phytopathology, Technical University of Munich, Freising-Weihenstephan, 85354, Germany
| | - Milena Schäffer
- TUM School of Life Sciences, Chair of Phytopathology, Technical University of Munich, Freising-Weihenstephan, 85354, Germany
| | - Lin-Jie Shu
- TUM School of Life Sciences, Chair of Phytopathology, Technical University of Munich, Freising-Weihenstephan, 85354, Germany
- Department of Biology, University of Fribourg, Fribourg, 1700, Switzerland
| | - Tina Illig
- TUM School of Life Sciences, Chair of Phytopathology, Technical University of Munich, Freising-Weihenstephan, 85354, Germany
| | - Sonja Eibel
- TUM School of Life Sciences, Chair of Phytopathology, Technical University of Munich, Freising-Weihenstephan, 85354, Germany
| | - Atiara Fernandez
- TUM School of Life Sciences, Chair of Phytopathology, Technical University of Munich, Freising-Weihenstephan, 85354, Germany
| | - Stefanie Ranf
- TUM School of Life Sciences, Chair of Phytopathology, Technical University of Munich, Freising-Weihenstephan, 85354, Germany
- Department of Biology, University of Fribourg, Fribourg, 1700, Switzerland
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2
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Ni C, Hong M. Oligomerization of drug transporters: Forms, functions, and mechanisms. Acta Pharm Sin B 2024; 14:1924-1938. [PMID: 38799641 PMCID: PMC11119549 DOI: 10.1016/j.apsb.2024.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/07/2023] [Accepted: 01/05/2024] [Indexed: 05/29/2024] Open
Abstract
Drug transporters are essential players in the transmembrane transport of a wide variety of clinical drugs. The broad substrate spectra and versatile distribution pattern of these membrane proteins infer their pharmacological and clinical significance. With our accumulating knowledge on the three-dimensional structure of drug transporters, their oligomerization status has become a topic of intense study due to the possible functional roles carried out by such kind of post-translational modification (PTM). In-depth studies of oligomeric complexes formed among drug transporters as well as their interactions with other regulatory proteins can help us better understand the regulatory mechanisms of these membrane proteins, provide clues for the development of novel drugs, and improve the therapeutic efficacy. In this review, we describe different oligomerization forms as well as their structural basis of major drug transporters in the ATP-binding cassette and solute carrier superfamilies, summarize our current knowledge on the influence of oligomerization for protein expression level and transport function of these membrane proteins, and discuss the regulatory mechanisms of oligomerization. Finally, we highlight the challenges associated with the current oligomerization studies and propose some thoughts on the pharmaceutical application of this important drug transporter PTM.
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Affiliation(s)
- Chunxu Ni
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Mei Hong
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, South China Agricultural University, Guangzhou 510642, China
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3
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Zoued A, Duneau JP, Cascales E. Bacterial One- and Two-Hybrid Assays to Monitor Transmembrane Helix Interactions. Methods Mol Biol 2024; 2715:259-271. [PMID: 37930534 DOI: 10.1007/978-1-0716-3445-5_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
In transenvelope multiprotein machines such as bacterial secretion systems, protein-protein interactions not only occur between soluble domains but might also be mediated by helix-helix contacts in the inner membrane. Several assays have been therefore developed to test homotypic and heterotypic interactions between transmembrane α-helices in their native membrane environment. Here, we provide detailed protocols for two genetic assays, TOXCAT and GALLEX, which are based on the reconstitution of dimeric regulators allowing the control of expression of reporter genes.
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Affiliation(s)
- Abdelrahim Zoued
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ, CNRS, Marseille, France
- Centre International de Recherche en Infectiologie, UMR5308, Université Claude Bernard Lyon 1 - INSERM - CNRS, Lyon, France
| | - Jean-Pierre Duneau
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ, CNRS, Marseille, France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ, CNRS, Marseille, France.
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Pashkova N, Peterson TA, Ptak CP, Winistorfer SC, Ahern CA, Shy ME, Piper RC. PMP22 associates with MPZ via their transmembrane domains and disrupting this interaction causes a loss-of-function phenotype similar to hereditary neuropathy associated with liability to pressure palsies (HNPP). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.24.573255. [PMID: 38187781 PMCID: PMC10769442 DOI: 10.1101/2023.12.24.573255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
PMP22 and MPZ are major myelin proteins in the peripheral nervous system. MPZ is a single pass integral membrane protein with an extracellular immunoglobulin (Ig)-like domain and works as an adhesion protein to hold myelin wraps together across the intraperiod line. Loss of MPZ causes severe demyelinating Charcot-Marie-Tooth (CMT) peripheral neuropathy. PMP22 is an integral membrane tetraspan protein belonging to the Claudin superfamily. Homozygous loss of PMP22 also leads to severe demyelinating neuropathy, and duplication of wildtype PMP22 causes the most common form of CMT, CMT1A. Yet the molecular functions provided by PMP22 and how its alteration causes CMT are unknown. Here we find that these abundant myelin proteins form a strong and specific complex. Mutagenesis and domain swapping experiments reveal that these proteins interact through interfaces within their transmembrane domains. We also find that the PMP22 A67T patient variant that causes an HNPP (Hereditary neuropathy with pressure palsies) phenotype, reflecting a heterozygous loss-of-function, maps to this interface. The PMP22 A67T variant results in the specific loss of MPZ association with PMP22 without affecting PMP22 localization to the plasma membrane or its interactions with other proteins. These data define the molecular basis for the MPZ∼PMP22 interaction and indicate that the MPZ∼PMP22 complex fulfills an important function in myelinating cells.
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Reth M. Discovering immunoreceptor coupling and organization motifs. Front Immunol 2023; 14:1253412. [PMID: 37731510 PMCID: PMC10507400 DOI: 10.3389/fimmu.2023.1253412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 08/11/2023] [Indexed: 09/22/2023] Open
Abstract
The recently determined cryo-EM structures of the T cell antigen receptor (TCR) and B cell antigen receptor (BCR) show in molecular details the interactions of the ligand-binding part with the signaling subunits but they do not reveal the signaling mechanism of these antigen receptors. Without knowing the molecular basis of antigen sensing by these receptors, a rational design of optimal vaccines is not possible. The existence of conserved amino acids (AAs) that are not involved in the subunit interaction suggests that antigen receptors form higher complexes and/or have lateral interactors that control their activity. Here, I describe evolutionary conserved leucine zipper (LZ) motifs within the transmembrane domains (TMD) of antigen and coreceptor components that are likely to be involved in the oligomerization and lateral interaction of antigen receptor complexes on T and B cells. These immunoreceptor coupling and organization motifs (ICOMs) are also found within the TMDs of other important receptor types and viral envelope proteins. This discovery suggests that antigen receptors do not function as isolated entities but rather as part of an ICOM-based interactome that controls their nanoscale organization on resting cells and their dynamic remodeling on activated lymphocytes.
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Affiliation(s)
- Michael Reth
- Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Signaling Research Centers CIBSS and BIOSS, University of Freiburg, Freiburg, Germany
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Kuntzel T, Spenlé C, Pham-Van LD, Birmpili D, Riou A, Loeuillet A, Charmarke-Askar I, Bagnard D. Implication of the Transmembrane Domain in the Interleukin 10 Receptor Platform Oligomerisation. Cells 2023; 12:1361. [PMID: 37408195 DOI: 10.3390/cells12101361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/19/2023] [Accepted: 05/03/2023] [Indexed: 07/07/2023] Open
Abstract
Interleukin 10 (IL-10) exerts anti-inflammatory and immune regulatory roles through its fixation to the IL-10 receptor (IL-10R). The two subunits (IL-10Rα and IL-10Rβ) organise themselves to form a hetero-tetramer to induce the activation of the transcription factor STAT3. We analysed the activation patterns of the IL-10R, especially the contribution of the transmembrane (TM) domain of the IL-10Rα and IL-10Rβ subunits, as evidence accumulates that this short domain has tremendous implications in receptor oligomerisation and activation. We also addressed whether targeting the TM domain of IL-10R with peptides mimicking the TM sequences of the subunits translates into biological consequences. The results illustrate the involvement of the TM domains from both subunits in receptor activation and feature a distinctive amino acid crucial for the interaction. The TM peptide targeting approach also appears to be suitable for modulating the activation of the receptor through its action on the dimerization capabilities of the TM domains and thereby constitutes a potential new strategy for the modulation of the inflammation in pathologic contexts.
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Affiliation(s)
- Thomas Kuntzel
- UMR7242 Biotechnology and Cell Signalling, Centre National de la Recherche Scientifique, Strasbourg Drug Discovery and Development Institute (IMS), University of Strasbourg, 67400 Illkirch-Graffenstaden, France
| | - Caroline Spenlé
- UMR7242 Biotechnology and Cell Signalling, Centre National de la Recherche Scientifique, Strasbourg Drug Discovery and Development Institute (IMS), University of Strasbourg, 67400 Illkirch-Graffenstaden, France
| | - Lucas D Pham-Van
- UMR7242 Biotechnology and Cell Signalling, Centre National de la Recherche Scientifique, Strasbourg Drug Discovery and Development Institute (IMS), University of Strasbourg, 67400 Illkirch-Graffenstaden, France
| | - Dafni Birmpili
- UMR7242 Biotechnology and Cell Signalling, Centre National de la Recherche Scientifique, Strasbourg Drug Discovery and Development Institute (IMS), University of Strasbourg, 67400 Illkirch-Graffenstaden, France
| | - Aurélien Riou
- UMR7242 Biotechnology and Cell Signalling, Centre National de la Recherche Scientifique, Strasbourg Drug Discovery and Development Institute (IMS), University of Strasbourg, 67400 Illkirch-Graffenstaden, France
| | - Aurore Loeuillet
- UMR7242 Biotechnology and Cell Signalling, Centre National de la Recherche Scientifique, Strasbourg Drug Discovery and Development Institute (IMS), University of Strasbourg, 67400 Illkirch-Graffenstaden, France
| | - Imane Charmarke-Askar
- UMR7242 Biotechnology and Cell Signalling, Centre National de la Recherche Scientifique, Strasbourg Drug Discovery and Development Institute (IMS), University of Strasbourg, 67400 Illkirch-Graffenstaden, France
| | - Dominique Bagnard
- UMR7242 Biotechnology and Cell Signalling, Centre National de la Recherche Scientifique, Strasbourg Drug Discovery and Development Institute (IMS), University of Strasbourg, 67400 Illkirch-Graffenstaden, France
- Ecole Supérieure de Biotechnologie de Strasbourg, 67400 Illkirch-Graffenstaden, France
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Braverman D, Gershberg J, Sal-Man N. The transmembrane domains of the type III secretion system effector Tir are involved in its secretion and cellular activities. Front Cell Infect Microbiol 2023; 13:1103552. [PMID: 36864885 PMCID: PMC9971567 DOI: 10.3389/fcimb.2023.1103552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 02/01/2023] [Indexed: 02/16/2023] Open
Abstract
Introduction Enteropathogenic Escherichia coli (EPEC) is a diarrheagenic pathogen and one of the major causes of gastrointestinal illness in developing countries. EPEC, similar to many other Gram-negative bacterial pathogens, possesses essential virulence machinery called the type III secretion system (T3SS) that enables the injection of effector proteins from the bacteria into the host cytoplasm. Of these, the translocated intimin receptor (Tir) is the first effector to be injected, and its activity is essential for the formation of attaching and effacing lesions, the hallmark of EPEC colonization. Tir belongs to a unique group of transmembrane domain (TMD)-containing secreted proteins, which have two conflicting destination indications, one for bacterial membrane integration and another for protein secretion. In this study, we examined whether TMDs participate in the secretion, translocation, and function of Tir in host cells. Methods We created Tir TMD variants with the original or alternative TMD sequence. Results We found that the C-terminal TMD of Tir (TMD2) is critical for the ability of Tir to escape integration into the bacterial membrane. However, the TMD sequence was not by itself sufficient and its effect was context-dependent. Moreover, the N-terminal TMD of Tir (TMD1) was important for the postsecretion function of Tir at the host cell. Discussion Taken together, our study further supports the hypothesis that the TMD sequences of translocated proteins encode information crucial for protein secretion and their postsecretion function.
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Affiliation(s)
- Dor Braverman
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Jenia Gershberg
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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8
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Singh DD, Lee HJ, Yadav DK. Clinical updates on tyrosine kinase inhibitors in HER2-positive breast cancer. Front Pharmacol 2022; 13:1089066. [PMID: 36578543 PMCID: PMC9792097 DOI: 10.3389/fphar.2022.1089066] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 11/30/2022] [Indexed: 12/14/2022] Open
Abstract
Breast cancer (BC) is caused by epigenetic modifications and genetic heterogeneity and exhibits various histological feature. HER2+ (Human epidermal growth factor receptor 2) is a more aggressive type of breast cancer, diagnosis and prognosis are difficult for HER2+ BC. Anti-HER2+ inhibitors have been effectively used for patient treatment. High mortality rate is reported in HER2+ BC, due to availability of limited therapeutic options. Despite advances in systemic medications to treat metastatic breast cancer (MBC), HER2-positive MBC is still challenging for patients and treating clinicians. The clinical characteristics of the disease have changed after treatment with HER2-targeted therapy. Various types of Tyrosine kinase inhibitors (TKIs) have been developed to treat patients with HER2+ BC including afatinib, lapatinib, neratinib, tucatinib, and pyrotinib, have been developed as HER2-targeted therapies. The antibody-drug conjugates adotrastuzumab, emtansine, famtrastuzumab, and deruxtecan, as well as the anti-HER2 monoclonal antibody pertuzumab are used in both early-stage and metastatic situations, either alone or in conjunction with chemotherapy and other HER2-targeting therapies. The emergence of drug resistance in anti-HER2 therapies has been observed. To overcome drug resistance and limited efficacy in current treatment options, nano formulations can be used in patients with HER2+ BC treatment. Anti-HER2 ligands can be used in various nano formulations to target HER2 receptors. Here we will discuss, targeted TKIs in patients with HER2+ BC, clinical studies of HER2+ targeted TKIs, mechanisms of resistance to HER2-directed therapies with new implications of TKIs in HER2+ MBC (metastatic breast cancer) and anti-HER2 ligand in various nano formulations to target HER2 receptors.
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Affiliation(s)
- Desh Deepak Singh
- Amity Institute of Biotechnology, Amity University Rajasthan, Jaipur, India
| | - Hae-Jeung Lee
- Department of Food and Nutrition, College of Bionano Technology, Gachon University, Seongnam-si, Gyeonggi-do, South Korea,*Correspondence: Hae-Jeung Lee, ; Dharmendra Kumar Yadav,
| | - Dharmendra Kumar Yadav
- Department of Pharmacy, Gachon Institute of Pharmaceutical Science, College of Pharmacy, Gachon University, Incheon, South Korea,*Correspondence: Hae-Jeung Lee, ; Dharmendra Kumar Yadav,
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The Role of Transmembrane Proteins in Plant Growth, Development, and Stress Responses. Int J Mol Sci 2022; 23:ijms232113627. [PMID: 36362412 PMCID: PMC9655316 DOI: 10.3390/ijms232113627] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
Transmembrane proteins participate in various physiological activities in plants, including signal transduction, substance transport, and energy conversion. Although more than 20% of gene products are predicted to be transmembrane proteins in the genome era, due to the complexity of transmembrane domains they are difficult to reliably identify in the predicted protein, and they may have different overall three-dimensional structures. Therefore, it is challenging to study their biological function. In this review, we describe the typical structures of transmembrane proteins and their roles in plant growth, development, and stress responses. We propose a model illustrating the roles of transmembrane proteins during plant growth and response to various stresses, which will provide important references for crop breeding.
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10
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Bloemeke N, Meighen‐Berger K, Hitzenberger M, Bach NC, Parr M, Coelho JPL, Frishman D, Zacharias M, Sieber SA, Feige MJ. Intramembrane client recognition potentiates the chaperone functions of calnexin. EMBO J 2022; 41:e110959. [PMID: 36314723 PMCID: PMC9753464 DOI: 10.15252/embj.2022110959] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022] Open
Abstract
One-third of the human proteome is comprised of membrane proteins, which are particularly vulnerable to misfolding and often require folding assistance by molecular chaperones. Calnexin (CNX), which engages client proteins via its sugar-binding lectin domain, is one of the most abundant ER chaperones, and plays an important role in membrane protein biogenesis. Based on mass spectrometric analyses, we here show that calnexin interacts with a large number of nonglycosylated membrane proteins, indicative of additional nonlectin binding modes. We find that calnexin preferentially bind misfolded membrane proteins and that it uses its single transmembrane domain (TMD) for client recognition. Combining experimental and computational approaches, we systematically dissect signatures for intramembrane client recognition by calnexin, and identify sequence motifs within the calnexin TMD region that mediate client binding. Building on this, we show that intramembrane client binding potentiates the chaperone functions of calnexin. Together, these data reveal a widespread role of calnexin client recognition in the lipid bilayer, which synergizes with its established lectin-based substrate binding. Molecular chaperones thus can combine different interaction modes to support the biogenesis of the diverse eukaryotic membrane proteome.
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Affiliation(s)
- Nicolas Bloemeke
- Department of Bioscience, Center for Functional Protein Assemblies (CPA), TUM School of Natural SciencesTechnical University of MunichGarchingGermany
| | - Kevin Meighen‐Berger
- Department of Bioscience, Center for Functional Protein Assemblies (CPA), TUM School of Natural SciencesTechnical University of MunichGarchingGermany
| | - Manuel Hitzenberger
- Department of Bioscience, Center for Functional Protein Assemblies (CPA), TUM School of Natural SciencesTechnical University of MunichGarchingGermany
| | - Nina C Bach
- Department of Bioscience, Center for Functional Protein Assemblies (CPA), TUM School of Natural SciencesTechnical University of MunichGarchingGermany
| | - Marina Parr
- Department of Bioinformatics, TUM School of Life SciencesTechnical University of MunichFreisingGermany
| | - Joao PL Coelho
- Department of Bioscience, Center for Functional Protein Assemblies (CPA), TUM School of Natural SciencesTechnical University of MunichGarchingGermany
| | - Dmitrij Frishman
- Department of Bioinformatics, TUM School of Life SciencesTechnical University of MunichFreisingGermany
| | - Martin Zacharias
- Department of Bioscience, Center for Functional Protein Assemblies (CPA), TUM School of Natural SciencesTechnical University of MunichGarchingGermany
| | - Stephan A Sieber
- Department of Bioscience, Center for Functional Protein Assemblies (CPA), TUM School of Natural SciencesTechnical University of MunichGarchingGermany
| | - Matthias J Feige
- Department of Bioscience, Center for Functional Protein Assemblies (CPA), TUM School of Natural SciencesTechnical University of MunichGarchingGermany
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Li Q, Kang C. Dengue virus NS4B protein as a target for developing antivirals. Front Cell Infect Microbiol 2022; 12:959727. [PMID: 36017362 PMCID: PMC9398000 DOI: 10.3389/fcimb.2022.959727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/21/2022] [Indexed: 12/04/2022] Open
Abstract
Dengue virus is an important pathogen affecting global population while no specific treatment is available against this virus. Effort has been made to develop inhibitors through targeting viral nonstructural proteins such as NS3 and NS5 with enzymatic activities. No potent inhibitors entering clinical studies have been developed so far due to many challenges. The genome of dengue virus encodes four membrane-bound nonstructural proteins which do not possess any enzymatic activities. Studies have shown that the membrane protein-NS4B is a validated target for drug discovery and several NS4B inhibitors exhibited antiviral activities in various assays and entered preclinical studies.. Here, we summarize the recent studies on dengue NS4B protein. The structure and membrane topology of dengue NS4B derived from biochemical and biophysical studies are described. Function of NS4B through protein-protein interactions and some available NS4B inhibitors are summarized. Accumulated studies demonstrated that cell-based assays play important roles in developing NS4B inhibitors. Although the atomic structure of NS4B is not obtained, target-based drug discovery approach become feasible to develop NS4B inhibitors as recombinant NS4B protein is available.
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Affiliation(s)
- Qingxin Li
- Guangdong Provincial Engineering Laboratory of Biomass High Value Utilization, Institute of Biological and Medical Engineering, Guangdong Academy of Sciences, Guangzhou, China
- *Correspondence: Qingxin Li, ; Congbao Kang,
| | - Congbao Kang
- Experimental Drug Development Centre, Agency for Science, Technology and Research, Singapore, Singapore
- *Correspondence: Qingxin Li, ; Congbao Kang,
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Zimmermann M, Minuzzi L, Aliaga Aliaga A, Guiot MC, Hall JA, Soucy JP, Massarweh G, El Mestikawy S, Rosa-Neto P, Kobayashi E. Reduced Metabotropic Glutamate Receptor Type 5 Availability in the Epileptogenic Hippocampus: An in vitro Study. Front Neurol 2022; 13:888479. [PMID: 35937057 PMCID: PMC9355376 DOI: 10.3389/fneur.2022.888479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/02/2022] [Indexed: 11/23/2022] Open
Abstract
Abnormalities in the expression of metabotropic glutamate receptor type 5 (mGluR5) have been observed in the hippocampus of patients with drug-resistant mesial Temporal Lobe Epilepsy (mTLE). Ex-vivo studies in mTLE hippocampal surgical specimens have shown increased mGluR5 immunoreactivity, while in vivo whole brain imaging using positron emission tomography (PET) demonstrated reduced hippocampal mGluR5 availability. To further understand mGluR5 abnormalities in mTLE, we performed a saturation autoradiography study with [3H]ABP688 (a negative mGluR5 allosteric modulator). We aimed to evaluate receptor density (Bmax) and dissociation constants (KD) in hippocampal mTLE surgical specimens and in non-epilepsy hippocampi from necropsy controls. mTLE specimens showed a 43.4% reduction in receptor density compared to control hippocampi, which was independent of age, sex and KD (multiple linear regression analysis). There was no significant difference in KD between the groups, which suggests that the decreased mGluR5 availability found in vivo with PET cannot be attributed to reduced affinity between ligand and binding site. The present study supports that changes within the epileptogenic tissue include mGluR5 internalization or conformational changes that reduce [3H]ABP688 binding, as previously suggested in mTLE patients studied in vivo.
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Affiliation(s)
- Maria Zimmermann
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
- Translational Neuroimaging Laboratory, Douglas Research Institute, McGill University, Montréal, QC, Canada
| | - Luciano Minuzzi
- Translational Neuroimaging Laboratory, Douglas Research Institute, McGill University, Montréal, QC, Canada
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
| | - Arturo Aliaga Aliaga
- Translational Neuroimaging Laboratory, Douglas Research Institute, McGill University, Montréal, QC, Canada
- PET Unit, McConnell Brain Imaging Centre, Montréal, QC, Canada
| | | | - Jeffery A. Hall
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Jean-Paul Soucy
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
- PET Unit, McConnell Brain Imaging Centre, Montréal, QC, Canada
| | | | - Salah El Mestikawy
- Department of Psychiatry, Douglas Research Institute, McGill University, Montréal, QC, Canada
| | - Pedro Rosa-Neto
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
- Translational Neuroimaging Laboratory, Douglas Research Institute, McGill University, Montréal, QC, Canada
| | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
- *Correspondence: Eliane Kobayashi
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13
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Bleffert F, Granzin J, Caliskan M, Schott-Verdugo SN, Siebers M, Thiele B, Rahme LG, Felgner S, Dörmann P, Gohlke H, Batra-Safferling R, Erich-Jäger K, Kovacic F. Structural, mechanistic and physiological insights into phospholipase A-mediated membrane phospholipid degradation in Pseudomonas aeruginosa. eLife 2022; 11:72824. [PMID: 35536643 PMCID: PMC9132575 DOI: 10.7554/elife.72824] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 05/10/2022] [Indexed: 11/18/2022] Open
Abstract
Cells steadily adapt their membrane glycerophospholipid (GPL) composition to changing environmental and developmental conditions. While the regulation of membrane homeostasis via GPL synthesis in bacteria has been studied in detail, the mechanisms underlying the controlled degradation of endogenous GPLs remain unknown. Thus far, the function of intracellular phospholipases A (PLAs) in GPL remodeling (Lands cycle) in bacteria is not clearly established. Here, we identified the first cytoplasmic membrane-bound phospholipase A1 (PlaF) from Pseudomonas aeruginosa, which might be involved in the Lands cycle. PlaF is an important virulence factor, as the P. aeruginosa ΔplaF mutant showed strongly attenuated virulence in Galleria mellonella and macrophages. We present a 2.0-Å-resolution crystal structure of PlaF, the first structure that reveals homodimerization of a single-pass transmembrane (TM) full-length protein. PlaF dimerization, mediated solely through the intermolecular interactions of TM and juxtamembrane regions, inhibits its activity. The dimerization site and the catalytic sites are linked by an intricate ligand-mediated interaction network, which might explain the product (fatty acid) feedback inhibition observed with the purified PlaF protein. We used molecular dynamics simulations and configurational free energy computations to suggest a model of PlaF activation through a coupled monomerization and tilting of the monomer in the membrane, which constrains the active site cavity into contact with the GPL substrates. Thus, these data show the importance of the PlaF-mediated GPL remodeling pathway for virulence and could pave the way for the development of novel therapeutics targeting PlaF.
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Affiliation(s)
- Florian Bleffert
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Duesseldorf, Germany
| | | | - Muttalip Caliskan
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Duesseldorf, Germany
| | - Stephan N Schott-Verdugo
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Duesseldorf, Germany
| | - Meike Siebers
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Bonn, Germany
| | | | - Laurence G Rahme
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
| | - Sebastian Felgner
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Peter Dörmann
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Bonn, Germany
| | - Holger Gohlke
- Heinrich Heine University Düsseldorf, Dusseldorf, Germany
| | | | - Karl Erich-Jäger
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Duesseldorf, Germany
| | - Filip Kovacic
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Duesseldorf, Germany
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14
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Tseytin I, Lezerovich S, David N, Sal-Man N. Interactions and substrate selectivity within the SctRST complex of the type III secretion system of enteropathogenic Escherichia coli. Gut Microbes 2022; 14:2013763. [PMID: 34965187 PMCID: PMC8726614 DOI: 10.1080/19490976.2021.2013763] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 02/04/2023] Open
Abstract
Many bacterial pathogens employ a protein complex, termed the type III secretion system (T3SS), to inject bacterial effectors into host cells. These effectors manipulate various cellular processes to promote bacterial growth and survival. The T3SS complex adopts a nano-syringe shape that is assembled across the bacterial membranes, with an extracellular needle extending toward the host cell membrane. The assembly of the T3SS is initiated by the association of three proteins, known as SctR, SctS, and SctT, which create an entry portal to the translocation channel within the bacterial inner membrane. Using the T3SS of enteropathogenic Escherichia coli, we investigated, by mutational and functional analyses, the role of two structural construction sites formed within the SctRST complex and revealed that they are mutation-resistant components that are likely to act as seals preventing leakage of ions and metabolites rather than as substrate gates. In addition, we identified two residues in the SctS protein, Pro23, and Lys54, that are critical for the proper activity of the T3SS. We propose that Pro23 is critical for the physical orientation of the SctS transmembrane domains that create the tip of the SctRST complex and for their positioning with regard to other T3SS substructures. Surprisingly, we found that SctS Lys54, which was previously suggested to mediate the SctS self-oligomerization, is critical for T3SS activity due to its essential role in SctS-SctT hetero-interactions.
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Affiliation(s)
- Irit Tseytin
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Shir Lezerovich
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Nofar David
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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15
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Mitrović B, Lezerovich S, Sal-Man N. The Role of the Membrane-Associated Domain of the Export Apparatus Protein, EscV (SctV), in the Activity of the Type III Secretion System. Front Microbiol 2021; 12:719469. [PMID: 34413845 PMCID: PMC8369761 DOI: 10.3389/fmicb.2021.719469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 07/05/2021] [Indexed: 11/13/2022] Open
Abstract
Diarrheal diseases remain a major public health concern worldwide. Many of the causative bacterial pathogens that cause these diseases have a specialized protein complex, the type III secretion system (T3SS), which delivers effector proteins directly into host cells. These effectors manipulate host cell processes for the benefit of the infecting bacteria. The T3SS structure resembles a syringe anchored within the bacterial membrane, projecting toward the host cell membrane. The entry port of the T3SS substrates, called the export apparatus, is formed by five integral membrane proteins. Among the export apparatus proteins, EscV is the largest, and as it forms a nonamer, it constitutes the largest portion of the export apparatus complex. While there are considerable data on the soluble cytoplasmic domain of EscV, our knowledge of its membrane-associated section and its transmembrane domains (TMDs) is still very limited. In this study, using an isolated genetic reporter system, we found that TMD5 and TMD6 of EscV mediate strong self-oligomerization. Substituting these TMDs within the full-length protein with a random hydrophobic sequence resulted in a complete loss of function of the T3SS, further suggesting that the EscV TMD5 and TMD6 sequences have a functional role in addition to their structural role as membrane anchors. As we observed only mild reduction in the ability of the TMD-exchanged variants to integrate into the full or intermediate T3SS complexes, we concluded that EscV TMD5 and TMD6 are not crucial for the global assembly or stability of the T3SS complex but are rather involved in promoting the necessary TMD–TMD interactions within the complex and the overall TMD orientation to allow channel opening for the entry of T3SS substrates.
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Affiliation(s)
- Boško Mitrović
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Shir Lezerovich
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
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16
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Interhelical H-Bonds Modulate the Activity of a Polytopic Transmembrane Kinase. Biomolecules 2021; 11:biom11070938. [PMID: 34201916 PMCID: PMC8301901 DOI: 10.3390/biom11070938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 12/13/2022] Open
Abstract
DesK is a Histidine Kinase that allows Bacillus subtilis to maintain lipid homeostasis in response to changes in the environment. It is located in the membrane, and has five transmembrane helices and a cytoplasmic catalytic domain. The transmembrane region triggers the phosphorylation of the catalytic domain as soon as the membrane lipids rigidify. In this research, we study how transmembrane inter-helical interactions contribute to signal transmission; we designed a co-expression system that allows studying in vivo interactions between transmembrane helices. By Alanine-replacements, we identified a group of polar uncharged residues, whose side chains contain hydrogen-bond donors or acceptors, which are required for the interaction with other DesK transmembrane helices; a particular array of H-bond- residues plays a key role in signaling, transmitting information detected at the membrane level into the cell to finally trigger an adaptive response.
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17
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Quistgaard EM. BAP31: Physiological functions and roles in disease. Biochimie 2021; 186:105-129. [PMID: 33930507 DOI: 10.1016/j.biochi.2021.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/22/2022]
Abstract
B-cell receptor-associated protein 31 (BAP31 or BCAP31) is a ubiquitously expressed transmembrane protein found mainly in the endoplasmic reticulum (ER), including in mitochondria-associated membranes (MAMs). It acts as a broad-specificity membrane protein chaperone and quality control factor, which can promote different fates for its clients, including ER retention, ER export, ER-associated degradation (ERAD), or evasion of degradation, and it also acts as a MAM tetherer and regulatory protein. It is involved in several cellular processes - it supports ER and mitochondrial homeostasis, promotes proliferation and migration, plays several roles in metabolism and the immune system, and regulates autophagy and apoptosis. Full-length BAP31 can be anti-apoptotic, but can also mediate activation of caspase-8, and itself be cleaved by caspase-8 into p20-BAP31, which promotes apoptosis by mobilizing ER calcium stores at MAMs. BAP31 loss-of-function mutations is the cause of 'deafness, dystonia, and central hypomyelination' (DDCH) syndrome, characterized by severe neurological symptoms and early death. BAP31 is furthermore implicated in a growing number of cancers and other diseases, and several viruses have been found to target it to promote their survival or life cycle progression. The purpose of this review is to provide an overview and examination of the basic properties, functions, mechanisms, and roles in disease of BAP31.
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Affiliation(s)
- Esben M Quistgaard
- Department of Molecular Biology and Genetics - DANDRITE, Aarhus University, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
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18
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Muller YD, Nguyen DP, Ferreira LMR, Ho P, Raffin C, Valencia RVB, Congrave-Wilson Z, Roth TL, Eyquem J, Van Gool F, Marson A, Perez L, Wells JA, Bluestone JA, Tang Q. The CD28-Transmembrane Domain Mediates Chimeric Antigen Receptor Heterodimerization With CD28. Front Immunol 2021; 12:639818. [PMID: 33833759 PMCID: PMC8021955 DOI: 10.3389/fimmu.2021.639818] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/08/2021] [Indexed: 12/12/2022] Open
Abstract
Anti-CD19 chimeric antigen receptor (CD19-CAR)-engineered T cells are approved therapeutics for malignancies. The impact of the hinge domain (HD) and the transmembrane domain (TMD) between the extracellular antigen-targeting CARs and the intracellular signaling modalities of CARs has not been systemically studied. In this study, a series of 19-CARs differing only by their HD (CD8, CD28, or IgG4) and TMD (CD8 or CD28) was generated. CARs containing a CD28-TMD, but not a CD8-TMD, formed heterodimers with the endogenous CD28 in human T cells, as shown by co-immunoprecipitation and CAR-dependent proliferation of anti-CD28 stimulation. This dimerization was dependent on polar amino acids in the CD28-TMD and was more efficient with CARs containing CD28 or CD8 HD than IgG4-HD. The CD28-CAR heterodimers did not respond to CD80 and CD86 stimulation but had a significantly reduced CD28 cell-surface expression. These data unveiled a fundamental difference between CD28-TMD and CD8-TMD and indicated that CD28-TMD can modulate CAR T-cell activities by engaging endogenous partners.
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Affiliation(s)
- Yannick D Muller
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States.,Diabetes Center, University of California, San Francisco, San Francisco, CA, United States.,Department of Medicine, Service Immunologie et Allergie, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Duy P Nguyen
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, United States
| | - Leonardo M R Ferreira
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States.,Diabetes Center, University of California, San Francisco, San Francisco, CA, United States.,Sean N. Parker Autoimmune Research Laboratory, University of California, San Francisco, San Francisco, CA, United States
| | - Patrick Ho
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States.,Diabetes Center, University of California, San Francisco, San Francisco, CA, United States.,Sean N. Parker Autoimmune Research Laboratory, University of California, San Francisco, San Francisco, CA, United States
| | - Caroline Raffin
- Diabetes Center, University of California, San Francisco, San Francisco, CA, United States.,Sean N. Parker Autoimmune Research Laboratory, University of California, San Francisco, San Francisco, CA, United States
| | | | - Zion Congrave-Wilson
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Theodore L Roth
- Diabetes Center, University of California, San Francisco, San Francisco, CA, United States.,Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Justin Eyquem
- Sean N. Parker Autoimmune Research Laboratory, University of California, San Francisco, San Francisco, CA, United States
| | - Frederic Van Gool
- Diabetes Center, University of California, San Francisco, San Francisco, CA, United States.,Sean N. Parker Autoimmune Research Laboratory, University of California, San Francisco, San Francisco, CA, United States
| | - Alexander Marson
- Diabetes Center, University of California, San Francisco, San Francisco, CA, United States.,Department of Medicine, University of California, San Francisco, San Francisco, CA, United States.,Gladstone-UCSF Institute of Genomic Immunology, Gladstone Institutes, San Francisco, CA, United States
| | - Laurent Perez
- Department of Medicine, Service Immunologie et Allergie, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - James A Wells
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, United States.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, United States
| | - Jeffrey A Bluestone
- Diabetes Center, University of California, San Francisco, San Francisco, CA, United States.,Sean N. Parker Autoimmune Research Laboratory, University of California, San Francisco, San Francisco, CA, United States
| | - Qizhi Tang
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States.,Diabetes Center, University of California, San Francisco, San Francisco, CA, United States
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19
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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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20
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Morozov SY, Solovyev AG. Small hydrophobic viral proteins involved in intercellular movement of diverse plant virus genomes. AIMS Microbiol 2020; 6:305-329. [PMID: 33134746 PMCID: PMC7595835 DOI: 10.3934/microbiol.2020019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/13/2020] [Indexed: 12/12/2022] Open
Abstract
Most plant viruses code for movement proteins (MPs) targeting plasmodesmata to enable cell-to-cell and systemic spread in infected plants. Small membrane-embedded MPs have been first identified in two viral transport gene modules, triple gene block (TGB) coding for an RNA-binding helicase TGB1 and two small hydrophobic proteins TGB2 and TGB3 and double gene block (DGB) encoding two small polypeptides representing an RNA-binding protein and a membrane protein. These findings indicated that movement gene modules composed of two or more cistrons may encode the nucleic acid-binding protein and at least one membrane-bound movement protein. The same rule was revealed for small DNA-containing plant viruses, namely, viruses belonging to genus Mastrevirus (family Geminiviridae) and the family Nanoviridae. In multi-component transport modules the nucleic acid-binding MP can be viral capsid protein(s), as in RNA-containing viruses of the families Closteroviridae and Potyviridae. However, membrane proteins are always found among MPs of these multicomponent viral transport systems. Moreover, it was found that small membrane MPs encoded by many viruses can be involved in coupling viral replication and cell-to-cell movement. Currently, the studies of evolutionary origin and functioning of small membrane MPs is regarded as an important pre-requisite for understanding of the evolution of the existing plant virus transport systems. This paper represents the first comprehensive review which describes the whole diversity of small membrane MPs and presents the current views on their role in plant virus movement.
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Affiliation(s)
- Sergey Y Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.,Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia
| | - Andrey G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.,Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia.,Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
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21
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The Molecular Basis and Biologic Significance of the β-Dystroglycan-Emerin Interaction. Int J Mol Sci 2020; 21:ijms21175944. [PMID: 32824881 PMCID: PMC7504044 DOI: 10.3390/ijms21175944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/29/2020] [Accepted: 08/04/2020] [Indexed: 01/04/2023] Open
Abstract
β-dystroglycan (β-DG) assembles with lamins A/C and B1 and emerin at the nuclear envelope (NE) to maintain proper nuclear architecture and function. To provide insight into the nuclear function of β-DG, we characterized the interaction between β-DG and emerin at the molecular level. Emerin is a major NE protein that regulates multiple nuclear processes and whose deficiency results in Emery–Dreifuss muscular dystrophy (EDMD). Using truncated variants of β-DG and emerin, via a series of in vitro and in vivo binding experiments and a tailored computational analysis, we determined that the β-DG–emerin interaction is mediated at least in part by their respective transmembrane domains (TM). Using surface plasmon resonance assays we showed that emerin binds to β-DG with high affinity (KD in the nanomolar range). Remarkably, the analysis of cells in which DG was knocked out demonstrated that loss of β-DG resulted in a decreased emerin stability and impairment of emerin-mediated processes. β-DG and emerin are reciprocally required for their optimal targeting within the NE, as shown by immunofluorescence, western blotting and immunoprecipitation assays using emerin variants with mutations in the TM domain and B-lymphocytes of a patient with EDMD. In summary, we demonstrated that β-DG plays a role as an emerin interacting partner modulating its stability and function.
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22
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Yadavalli SS, Goh T, Carey JN, Malengo G, Vellappan S, Nickels BE, Sourjik V, Goulian M, Yuan J. Functional determinants of a small protein controlling a broadly conserved bacterial sensor kinase. J Bacteriol 2020; 202:JB.00305-20. [PMID: 32482726 PMCID: PMC8404706 DOI: 10.1128/jb.00305-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 12/14/2022] Open
Abstract
The PhoQ/PhoP two-component system plays a vital role in the regulation of Mg2+ homeostasis, resistance to acid and hyperosmotic stress, cationic antimicrobial peptides, and virulence in Escherichia coli, Salmonella and related bacteria. Previous studies have shown that MgrB, a 47 amino acid membrane protein that is part of the PhoQ/PhoP regulon, inhibits the histidine kinase PhoQ. MgrB is part of a negative feedback loop modulating this two-component system that prevents hyperactivation of PhoQ and may also provide an entry point for additional input signals for the PhoQ/PhoP pathway. To explore the mechanism of action of MgrB, we have analyzed the effects of point mutations, C-terminal truncations and transmembrane region swaps on MgrB activity. In contrast with two other known membrane protein regulators of histidine kinases in E. coli, we find that the MgrB TM region is necessary for PhoQ inhibition. Our results indicate that the TM region mediates interactions with PhoQ and that W20 is a key residue for PhoQ/MgrB complex formation. Additionally, mutations of the MgrB cytosolic region suggest that the two N-terminal lysines play an important role in regulating PhoQ activity. Alanine scanning mutagenesis of the periplasmic region of MgrB further indicates that, with the exception of a few highly conserved residues, most residues are not essential for MgrB's function as a PhoQ inhibitor. Our results indicate that the regulatory function of the small protein MgrB depends on distinct contributions from multiple residues spread across the protein. Interestingly, the TM region also appears to interact with other non-cognate histidine kinases in a bacterial two-hybrid assay, suggesting a potential route for evolving new small protein modulators of histidine kinases.
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Affiliation(s)
- Srujana S Yadavalli
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Genetics and Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854, USA
| | - Ted Goh
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania 19081, USA
- Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Jeffrey N Carey
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Gabriele Malengo
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany
| | - Sangeevan Vellappan
- Molecular Biosciences Graduate Program, Rutgers University, Piscataway NJ 08854
| | - Bryce E Nickels
- Department of Genetics and Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854, USA
| | - Victor Sourjik
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany
| | - Mark Goulian
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jing Yuan
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany
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23
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Gopal SM, Pawar AB, Wassenaar TA, Sengupta D. Lipid-dependent conformational landscape of the ErbB2 growth factor receptor dimers. Chem Phys Lipids 2020; 230:104911. [PMID: 32353357 DOI: 10.1016/j.chemphyslip.2020.104911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/04/2020] [Accepted: 03/27/2020] [Indexed: 01/31/2023]
Abstract
Altered lipid metabolism has been linked to cancer development and progression. Several roles have been attributed to the increased saturation and length of lipid acyl tails observed in tumors, but its effect on signaling receptors is still emerging. In this work, we have analyzed the lipid dependence of the ErbB2 growth factor receptor dimerization that plays an important role in the pathogenesis of breast cancer. We have performed coarse-grain ensemble molecular dynamics simulations to comprehensively sample the ErbB2 monomer-dimer association. Our results indicate a dynamic dimer state with a complex conformational landscape that is modulated with increasing lipid tail length. We resolve the native N-terminal "active" and C-terminal "inactive" conformations in all membrane compositions. However, the relative population of the N-terminal and C-terminal conformers is dependent on length of the saturated lipid tails. In short-tail membranes, additional non-specific dimers are observed which are reduced or absent in long-tailed bilayers. Our results indicate that the relative population as well as the structure of the dimer state is modulated by membrane composition. We have correlated these differences to local perturbations of the membrane around the receptor. Our work is an important step in characterizing ErbB dimers in healthy and diseased states and emphasize the importance of sampling lipid dynamics in understanding receptor association.
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Affiliation(s)
- Srinivasa M Gopal
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India; Lehrstuhl fur Theoretische Chemie, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Aiswarya B Pawar
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India; AcSIR, Mathura Road, New Delhi, 110 025, India
| | - Tsjerk A Wassenaar
- Molecular Dynamics, University of Groningen, Nijenborgh 7, 9747AG Groningen, the Netherlands
| | - Durba Sengupta
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India; AcSIR, Mathura Road, New Delhi, 110 025, India.
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Al-Darkazly IAA, Hasan SMR. Extra-Low-Frequency Pulse Stimulated Conformational Change in Blood-Cell Proteins and Consequent Immune Activity Transformation. IEEE JOURNAL OF TRANSLATIONAL ENGINEERING IN HEALTH AND MEDICINE 2020; 8:4100113. [PMID: 31998567 PMCID: PMC6984198 DOI: 10.1109/jtehm.2020.2963894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/12/2019] [Accepted: 12/30/2019] [Indexed: 11/16/2022]
Abstract
Objective: investigation of the extra-low-frequency (ELF) stimulation effect on blood-cell proteins, that causes variation in its electrostatic-state. A hypothesis that this results in the conformational change in the blood-cell proteins which could enhance immune activity is explored. Since HIV-1 and host-cell engage through charge-charge interactions, an electrical-pulse may cause charge redistribution, hypothetically resulting in host-cell proteins to be isolated from viral access. Methods: Buffy coat samples were exposed to ELF square waveform pulses of 5Hz, 10Hz and 1MHz, for 2-hours, and were then examined using immunofluorescence technique. The expression of glycoprotein CD4, and co-receptor protein CCR5, were investigated. Also, the binding activity of the N-terminal domain of CCR5 and the distribution of the nuclear-pore-complex (NPC) transport factor, FGNup153 were investigated. Comparison with control samples were carried out. Results: Increased CD4 count, which could enhance the immune system. In addition, the inability of N-terminus-specific antibody 3A9 to bind to CCR5 N-terminal, could be due to the interactions with the ELF electric-field, which may also hypothetically inhibit HIV-1 attachment. Furthermore, the electrostatic interactions between the ELF pulse and the FGNup153 induces redistribution in its disorder sequence and possibly causes conformational change. This could possibly prevent large virus particle transport through the NPC. Conclusion: Novel concept of ELF stimulation of blood cellular proteins has been developed leading to transformation of immune activity. Clinical-Impact: The translational aspect is the use of ELF as an avenue of electro-medicine and the results are a possible foundation for the clinical application of ELF stimulation in immune response.
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Affiliation(s)
- Ibtisam A. Abbas Al-Darkazly
- Center for Research in Analog and VLSI Microsystems Design (CRAVE), School of Advanced TechnologyMassey UniversityAuckland0632New Zealand
| | - S. M. Rezaul Hasan
- Center for Research in Analog and VLSI Microsystems Design (CRAVE), School of Advanced TechnologyMassey UniversityAuckland0632New Zealand
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Enhanced oligomerization of full-length RAGE by synergy of the interaction of its domains. Sci Rep 2019; 9:20332. [PMID: 31889156 PMCID: PMC6937306 DOI: 10.1038/s41598-019-56993-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 12/11/2019] [Indexed: 01/10/2023] Open
Abstract
The pattern recognition receptor RAGE (receptor for advanced glycation end-products) transmits proinflammatory signals in several inflammation-related pathological states, including vascular diseases, cancer, neurodegeneration and diabetes. Its oligomerization is believed to be important in signal transduction, but RAGE oligomeric structures and stoichiometries remain unclear. Different oligomerization modes have been proposed in studies involving different truncated versions of the extracellular parts of RAGE. Here, we provide basic characterization of the oligomerization patterns of full-length RAGE (including the transmembrane (TM) and cytosolic regions) and compare the results with oligomerization modes of its four truncated fragments. For this purpose, we used native mass spectrometry, analytical ultracentrifugation, and size-exclusion chromatography coupled with multi-angle light scattering. Our results confirm known oligomerization tendencies of separate domains and highlight the enhanced oligomerization properties of full-length RAGE. Mutational analyses within the GxxxG motif of the TM region show sensitivity of oligomeric distributions to the TM sequence. Using hydrogen–deuterium exchange, we mapped regions involved in TM-dependent RAGE oligomerization. Our data provide experimental evidence for the major role of the C2 and TM domains in oligomerization, underscoring synergy among different oligomerization contact regions along the RAGE sequence. These results also explain the variability of obtained oligomerization modes in RAGE fragments.
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Tseytin I, Mitrovic B, David N, Langenfeld K, Zarivach R, Diepold A, Sal-Man N. The Role of the Small Export Apparatus Protein, SctS, in the Activity of the Type III Secretion System. Front Microbiol 2019; 10:2551. [PMID: 31798543 PMCID: PMC6863770 DOI: 10.3389/fmicb.2019.02551] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/22/2019] [Indexed: 12/15/2022] Open
Abstract
Many gram-negative pathogens utilize a protein complex, termed the type III secretion system (T3SS), to inject virulence factors from their cytoplasm directly into the host cell. An export apparatus that is formed by five putative integral membrane proteins (SctR/S/T/U/V), resides at the center of the T3SS complex. In this study, we characterized the smallest export apparatus protein, SctS, which contains two putative transmembrane domains (PTMD) that dynamically extract from the inner membrane and adopt a helix-turn-helix structure upon assembly of the T3SS. Replacement of each SctS PTMD with an alternative hydrophobic sequence resulted in abolishment of the T3SS activity, yet SctS self- and hetero-interactions as well as the overall assembly of the T3SS complex were unaffected. Our findings suggest that SctS PTMDs are not crucial for the interactions or the assembly of the T3SS base complex but rather that they are involved in adjusting the orientation of the export apparatus relative to additional T3SS sub-structures, such as the cytoplasmic- and the inner-membrane rings. This ensures the fittings between the dynamic and static components of the T3SS and supports the functionality of the T3SS complex.
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Affiliation(s)
- Irit Tseytin
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Bosko Mitrovic
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Nofar David
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Katja Langenfeld
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Raz Zarivach
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
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Pannwitt S, Stangl M, Schneider D. Lipid Binding Controls Dimerization of the Coat Protein p24 Transmembrane Helix. Biophys J 2019; 117:1554-1562. [PMID: 31627840 DOI: 10.1016/j.bpj.2019.09.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 09/05/2019] [Accepted: 09/09/2019] [Indexed: 10/25/2022] Open
Abstract
Coat protein (COP) I and COP II complexes are involved in the transport of proteins between the endoplasmic reticulum and the Golgi apparatus in eukaryotic cells. The formation of COP I/II complexes at membrane surfaces is an early step in vesicle formation and is mastered by p24, a type I transmembrane protein. Oligomerization of p24 monomers was suggested to be mediated and/or stabilized via interactions within the transmembrane domain, and the p24 transmembrane helix appears to selectively bind a single sphingomyelin C18:0 molecule. Furthermore, a potential cholesterol-binding sequence has also been predicted in the p24 transmembrane domain. Thus, sphingomyelin and/or cholesterol binding to the transmembrane domain might directly control the oligomeric state of p24 and, thus, COP vesicle formation. In this study, we show that sequence-specific dimerization of the p24 transmembrane helix is mediated by a LQ7 motif, with Gln187 being of special importance. Whereas cholesterol has no direct impact on p24 dimerization, binding of the sphingolipid can clearly control dimerization of p24 in rigid membrane regions. We suggest that specific binding of a sphingolipid to the p24 transmembrane helix affects p24 dimerization in membranes with increased cholesterol contents. A clearly defined p24 dimerization propensity likely is crucial for the p24 activity, which involves shuttling in between the endoplasmic reticulum and the Golgi membrane, in which cholesterol and SM C18:0 concentrations differ.
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Affiliation(s)
- Stefanie Pannwitt
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Michael Stangl
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Dirk Schneider
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany.
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28
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Zeng B, Hönigschmid P, Frishman D. Residue co-evolution helps predict interaction sites in α-helical membrane proteins. J Struct Biol 2019; 206:156-169. [DOI: 10.1016/j.jsb.2019.02.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/30/2019] [Accepted: 02/13/2019] [Indexed: 11/29/2022]
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29
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Lien YH, Ram Mahato D, Hoppe-Seyler F, Fischer WB. Membrane partitioning of peptide aggregates: coarse-grained molecular dynamics simulations. J Biomol Struct Dyn 2019; 38:524-532. [PMID: 30774024 DOI: 10.1080/07391102.2019.1581660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Coarse-grained molecular dynamics (CGMD) simulation technique (MARTINI force field) is applied to monitor the aggregation of helical peptides representing the transmembrane sequence and its extension of bone marrow stromal cell antigen 2 (BST-2). One of the peptides is coupled with a protein transducing domain (PTD) of nine arginine residues (R9) at its N-terminal side as well as a peptide, pep11**, which has been shown to bind to human papilloma virus 16 (HPV16) E6 oncoprotein. A short hydrophobic stretch of the transmembrane domain (TMD) of BST-2 aggregates the fastest and inserts into a lipid membrane. An aggregate of R9-pep11** attaches to the membrane via simultaneous contact of many arginine residues. Monomers from the aggregates of the shortest of the hydrophobic TMDs dissolve into the opposing leaflet when the aggregate spans the bilayer. A 'flipping' of the individual monomeric peptides is not observed.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Yu-Hsien Lien
- Institute of Biophotonics, Biophotonics & Molecular Imaging Research Center (BMIRC), School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan
| | - Dhani Ram Mahato
- Institute of Biophotonics, Biophotonics & Molecular Imaging Research Center (BMIRC), School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan
| | | | - Wolfgang B Fischer
- Institute of Biophotonics, Biophotonics & Molecular Imaging Research Center (BMIRC), School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan
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30
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The Third Transmembrane Domain of EscR Is Critical for Function of the Enteropathogenic Escherichia coli Type III Secretion System. mSphere 2018; 3:3/4/e00162-18. [PMID: 30045964 PMCID: PMC6060343 DOI: 10.1128/msphere.00162-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Many Gram-negative bacterial pathogens that cause life-threatening diseases employ a type III secretion system (T3SS) for their virulence. The T3SS comprises several proteins that assemble into a syringe-like structure dedicated to the injection of bacterial virulence factors into the host cells. Although many T3SS proteins are transmembrane proteins, our knowledge of these proteins is limited mostly to their soluble domains. In this study, we found that the third transmembrane domain (TMD) of EscR, a central protein of the T3SS in enteropathogenic E. coli, contributes to protein self-oligomerization. Moreover, we demonstrated that a single aspartic acid residue, located at the core of this TMD, is critical for the activity of the full-length protein and the function of the entire T3SS, possibly due to its involvement in mediating TMD-TMD interactions. Our findings should encourage the mapping of the entire interactome of the T3SS components, including interactions mediated through their TMDs. Many Gram-negative bacterial pathogens utilize a specialized protein delivery system, called the type III secretion system (T3SS), to translocate effector proteins into the host cells. The translocated effectors are crucial for bacterial infection and survival. The base of the T3SS transverses both bacterial membranes and contains an export apparatus that comprises five membrane proteins. Here, we study the export apparatus of enteropathogenic Escherichia coli (EPEC) and characterize its central component, called the EscR protein. We found that the third transmembrane domain (TMD) of EscR mediates strong self-oligomerization in an isolated genetic reporter system. Replacing this TMD sequence with an alternative hydrophobic sequence within the full-length protein resulted in a complete loss of function of the T3SS, further suggesting that the EscR TMD3 sequence has another functional role in addition to its role as a membrane anchor. Moreover, we found that an aspartic acid residue, located at the core of EscR TMD3, is important for the oligomerization propensity of TMD3 and that a point mutation of this residue within the full-length protein abolishes the T3SS activity and the ability of the bacteria to translocate effectors into host cells. IMPORTANCE Many Gram-negative bacterial pathogens that cause life-threatening diseases employ a type III secretion system (T3SS) for their virulence. The T3SS comprises several proteins that assemble into a syringe-like structure dedicated to the injection of bacterial virulence factors into the host cells. Although many T3SS proteins are transmembrane proteins, our knowledge of these proteins is limited mostly to their soluble domains. In this study, we found that the third transmembrane domain (TMD) of EscR, a central protein of the T3SS in enteropathogenic E. coli, contributes to protein self-oligomerization. Moreover, we demonstrated that a single aspartic acid residue, located at the core of this TMD, is critical for the activity of the full-length protein and the function of the entire T3SS, possibly due to its involvement in mediating TMD-TMD interactions. Our findings should encourage the mapping of the entire interactome of the T3SS components, including interactions mediated through their TMDs.
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31
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Ahmed MM, Aboshanab KM, Ragab YM, Missiakas DM, Aly KA. The transmembrane domain of the Staphylococcus aureus ESAT-6 component EssB mediates interaction with the integral membrane protein EsaA, facilitating partially regulated secretion in a heterologous host. Arch Microbiol 2018; 200:1075-1086. [DOI: 10.1007/s00203-018-1519-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 04/24/2018] [Accepted: 04/24/2018] [Indexed: 10/17/2022]
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32
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Rotem E, Faingold O, Charni M, Klug YA, Harari D, Shmuel-Galia L, Nudelman A, Rotter V, Shai Y. The HTLV-1 gp21 fusion peptide inhibits antigen specific T-cell activation in-vitro and in mice. PLoS Pathog 2018; 14:e1007044. [PMID: 29727445 PMCID: PMC5955599 DOI: 10.1371/journal.ppat.1007044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/16/2018] [Accepted: 04/18/2018] [Indexed: 11/17/2022] Open
Abstract
The ability of the Lentivirus HIV-1 to inhibit T-cell activation by its gp41 fusion protein is well documented, yet limited data exists regarding other viral fusion proteins. HIV-1 utilizes membrane binding region of gp41 to inhibit T-cell receptor (TCR) complex activation. Here we examined whether this T-cell suppression strategy is unique to the HIV-1 gp41. We focused on T-cell modulation by the gp21 fusion peptide (FP) of the Human T-lymphotropic Virus 1 (HTLV-1), a Deltaretrovirus that like HIV infects CD4+ T-cells. Using mouse and human in-vitro T-cell models together with in-vivo T-cell hyper activation mouse model, we reveal that HTLV-1's FP inhibits T-cell activation and unlike the HIV FP, bypasses the TCR complex. HTLV FP inhibition induces a decrease in Th1 and an elevation in Th2 responses observed in mRNA, cytokine and transcription factor profiles. Administration of the HTLV FP in a T-cell hyper activation mouse model of multiple sclerosis alleviated symptoms and delayed disease onset. We further pinpointed the modulatory region within HTLV-1's FP to the same region previously identified as the HIV-1 FP active region, suggesting that through convergent evolution both viruses have obtained the ability to modulate T-cells using the same region of their fusion protein. Overall, our findings suggest that fusion protein based T-cell modulation may be a common viral trait.
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Affiliation(s)
- Etai Rotem
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Omri Faingold
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Meital Charni
- Department of molecular cell biology, The Weizmann Institute of Science, Rehovot, Israel
| | - Yoel A Klug
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Daniel Harari
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Liraz Shmuel-Galia
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Alon Nudelman
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Varda Rotter
- Department of molecular cell biology, The Weizmann Institute of Science, Rehovot, Israel
| | - Yechiel Shai
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
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33
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Bitler A, Dover RS, Shai Y. Fractal properties of cell surface structures: A view from AFM. Semin Cell Dev Biol 2018; 73:64-70. [DOI: 10.1016/j.semcdb.2017.07.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 07/10/2017] [Accepted: 07/13/2017] [Indexed: 01/08/2023]
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Okada R, Matsuda S, Iida T. Vibrio parahaemolyticus VtrA is a membrane-bound regulator and is activated via oligomerization. PLoS One 2017; 12:e0187846. [PMID: 29149170 PMCID: PMC5693285 DOI: 10.1371/journal.pone.0187846] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/29/2017] [Indexed: 12/31/2022] Open
Abstract
Vibrio parahaemolyticus is a Gram-negative pathogen that causes food-borne gastroenteritis. A major virulence determinant of the organism is a type III secretion system (T3SS2) encoded on a pathogenicity island, Vp-PAI. Vp-PAI gene expression is regulated by two transcriptional regulators, VtrA and VtrB, whose N-terminal regions share homology with an OmpR-family DNA-binding domain. VtrA activates the gene expression of VtrB, which in turn activates Vp-PAI gene expression; however, the mechanism of this transcriptional activation by VtrA is not well understood. In this study, we determined that VtrA is a membrane protein with a transmembrane (TM) domain, which was required for its transcriptional regulatory activity. Although the N-terminal region of VtrA alone is insufficient for its transcriptional regulatory activity, forced oligomerization using the leucine-zipper dimerization domain of yeast GCN4 conferred transcriptional regulatory activity and a greater affinity for the promoter region of vtrB. A ToxR-based assay demonstrated that VtrA oligomerizes in vivo. We also showed that bile, a host-derived activator of VtrA, induces the oligomerization of VtrA, which requires the C-terminal domain. The promoter region of vtrB contained repetitive T-rich DNA elements, which are important for vtrB transcriptional activation and are conserved among T3SS2-possessing Vibrio species. These findings propose that VtrA is active as oligomers, which may facilitate its N-terminus binding the target DNA, thus enhancing its transcriptional regulatory activity.
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Affiliation(s)
- Ryu Okada
- Department of Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Shigeaki Matsuda
- Department of Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- * E-mail:
| | - Tetsuya Iida
- Department of Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
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The role of EscD in supporting EscC polymerization in the type III secretion system of enteropathogenic Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:384-395. [PMID: 28988128 DOI: 10.1016/j.bbamem.2017.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 10/01/2017] [Accepted: 10/02/2017] [Indexed: 11/23/2022]
Abstract
The type III secretion system (T3SS) is a multi-protein complex that plays a central role in the virulence of many Gram-negative bacterial pathogens. In enteropathogenic Escherichia coli, a prevalent cause of diarrheal diseases, the needle complex base of the T3SS is formed by multi-rings: two concentric inner-membrane rings made by the two oligomerizing proteins (EscD and EscJ), and an outer ring made of a single oligomerizing protein (EscC). Although the oligomerization activity of these proteins is critical for their function and can, therefore, affect the virulence of the pathogen, the mechanisms underlying the oligomerization of these proteins have yet to be identified. In this study, we report that the proteins forming the inner-membrane T3SS rings, EscJ and EscD proteins, are crucial for the oligomerization of EscC. Moreover, we elucidate the oligomerization process of EscD and determine the contribution of individual regions of the protein to its self-oligomerization activity. We show that the oligomerization motif of EscD is located at its N-terminal portion and that its transmembrane domain can self-oligomerize, thus contributing to the self-oligomerization of the full-length EscD.
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36
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Zhou H, Wang C. Purification and function analysis of the Δ-17 fatty acid desaturase with or without transmembrane domain. Exp Ther Med 2017; 14:2117-2125. [PMID: 28962132 PMCID: PMC5609165 DOI: 10.3892/etm.2017.4790] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 04/11/2017] [Indexed: 11/05/2022] Open
Abstract
Fatty acid desaturation enzymes perform dehydrogenation reactions leading to the insertion of double bonds in fatty acids. ω-3 desaturase has an important role in converting ω-6 fatty acids into ω-3 fatty acids. Although genes for this desaturase have been identified, the enzymatic activity of Δ-17 with or without transmembrane domain, and the function of the Δ-17 desaturase is poorly understood. In the present study, a transgenic microorganism was used to clone the Δ-17 full length (Δ-17FL) and Δ-17 without transmembrane domain (Δ-17NT), the expression efficiency was improved and western blotting was used to detect the protein expression level. The purification of Δ-17 was precipitated using saturated ammonium sulfate solution, dissolved in phosphate buffered saline buffer, and then filtered using a 10 kDa ultrafiltration cube. Gas chromatography analysis was used to measure the effect of Δ-17NT or Δ-17FL expression on Pichia pastoris fatty acid composition. Furthermore, the function of Δ-17NT in HepG2 cells was measured and the mechanism was explored. It was demonstrated that Δ-17NT decreased cell growth and increased apoptosis in hepatocellular carcinoma cell lines in vitro. In conclusion, successful expression of high levels of recombinant Δ-17NT represents a critical step towards the elucidation of the function of membrane fatty acid desaturases.
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Affiliation(s)
- Haoyu Zhou
- Department of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430000, P.R. China
| | - Chengming Wang
- Department of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430000, P.R. China
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BLaTM 2.0, a Genetic Tool Revealing Preferred Antiparallel Interaction of Transmembrane Helix 4 of the Dual-Topology Protein EmrE. J Mol Biol 2017; 429:1630-1637. [DOI: 10.1016/j.jmb.2017.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 04/03/2017] [Accepted: 04/06/2017] [Indexed: 01/13/2023]
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38
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Schanzenbach C, Schmidt FC, Breckner P, Teese MG, Langosch D. Identifying ionic interactions within a membrane using BLaTM, a genetic tool to measure homo- and heterotypic transmembrane helix-helix interactions. Sci Rep 2017; 7:43476. [PMID: 28266525 PMCID: PMC5339904 DOI: 10.1038/srep43476] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/23/2017] [Indexed: 12/15/2022] Open
Abstract
The assembly of integral membrane protein complexes is frequently supported by transmembrane domain (TMD) interactions. Here, we present the BLaTM assay that measures homotypic as well as heterotypic TMD-TMD interactions in a bacterial membrane. The system is based on complementation of β-lactamase fragments genetically fused to interacting TMDs, which confers ampicillin resistance to expressing cells. We validated BLaTM by showing that the assay faithfully reports known sequence-specific interactions of both types. In a practical application, we used BLaTM to screen a focussed combinatorial library for heterotypic interactions driven by electrostatic forces. The results reveal novel patterns of ionizable amino acids within the isolated TMD pairs. Those patterns indicate that formation of heterotypic TMD pairs is most efficiently supported by closely spaced ionizable residues of opposite charge. In addition, TMD heteromerization can apparently be driven by hydrogen bonding between basic or between acidic residues.
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Affiliation(s)
- Christoph Schanzenbach
- Munich Center For Integrated Protein Science (CIPSM) at the Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Fabian C. Schmidt
- Munich Center For Integrated Protein Science (CIPSM) at the Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Patrick Breckner
- Munich Center For Integrated Protein Science (CIPSM) at the Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Mark G. Teese
- Munich Center For Integrated Protein Science (CIPSM) at the Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Dieter Langosch
- Munich Center For Integrated Protein Science (CIPSM) at the Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
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Webb S, Nagy T, Moseley H, Fried M, Dutch R. Hendra virus fusion protein transmembrane domain contributes to pre-fusion protein stability. J Biol Chem 2017; 292:5685-5694. [PMID: 28213515 DOI: 10.1074/jbc.m117.777235] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/15/2017] [Indexed: 12/29/2022] Open
Abstract
Enveloped viruses utilize fusion (F) proteins studding the surface of the virus to facilitate membrane fusion with a target cell membrane. Fusion of the viral envelope with a cellular membrane is required for release of viral genomic material, so the virus can ultimately reproduce and spread. To drive fusion, the F protein undergoes an irreversible conformational change, transitioning from a metastable pre-fusion conformation to a more thermodynamically stable post-fusion structure. Understanding the elements that control stability of the pre-fusion state and triggering to the post-fusion conformation is important for understanding F protein function. Mutations in F protein transmembrane (TM) domains implicated the TM domain in the fusion process, but the structural and molecular details in fusion remain unclear. Previously, analytical ultracentrifugation was utilized to demonstrate that isolated TM domains of Hendra virus F protein associate in a monomer-trimer equilibrium (Smith, E. C., Smith, S. E., Carter, J. R., Webb, S. R., Gibson, K. M., Hellman, L. M., Fried, M. G., and Dutch, R. E. (2013) J. Biol. Chem. 288, 35726-35735). To determine factors driving this association, 140 paramyxovirus F protein TM domain sequences were analyzed. A heptad repeat of β-branched residues was found, and analysis of the Hendra virus F TM domain revealed a heptad repeat leucine-isoleucine zipper motif (LIZ). Replacement of the LIZ with alanine resulted in dramatically reduced TM-TM association. Mutation of the LIZ in the whole protein resulted in decreased protein stability, including pre-fusion conformation stability. Together, our data suggest that the heptad repeat LIZ contributed to TM-TM association and is important for F protein function and pre-fusion stability.
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Affiliation(s)
- Stacy Webb
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
| | - Tamas Nagy
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
| | - Hunter Moseley
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
| | - Michael Fried
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
| | - Rebecca Dutch
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
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40
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Steindorf D, Schneider D. In vivo selection of heterotypically interacting transmembrane helices: Complementary helix surfaces, rather than conserved interaction motifs, drive formation of transmembrane hetero-dimers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:245-256. [DOI: 10.1016/j.bbamem.2016.11.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/23/2016] [Accepted: 11/29/2016] [Indexed: 11/16/2022]
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Venko K, Roy Choudhury A, Novič M. Computational Approaches for Revealing the Structure of Membrane Transporters: Case Study on Bilitranslocase. Comput Struct Biotechnol J 2017; 15:232-242. [PMID: 28228927 PMCID: PMC5312651 DOI: 10.1016/j.csbj.2017.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/19/2017] [Accepted: 01/20/2017] [Indexed: 11/23/2022] Open
Abstract
The structural and functional details of transmembrane proteins are vastly underexplored, mostly due to experimental difficulties regarding their solubility and stability. Currently, the majority of transmembrane protein structures are still unknown and this present a huge experimental and computational challenge. Nowadays, thanks to X-ray crystallography or NMR spectroscopy over 3000 structures of membrane proteins have been solved, among them only a few hundred unique ones. Due to the vast biological and pharmaceutical interest in the elucidation of the structure and the functional mechanisms of transmembrane proteins, several computational methods have been developed to overcome the experimental gap. If combined with experimental data the computational information enables rapid, low cost and successful predictions of the molecular structure of unsolved proteins. The reliability of the predictions depends on the availability and accuracy of experimental data associated with structural information. In this review, the following methods are proposed for in silico structure elucidation: sequence-dependent predictions of transmembrane regions, predictions of transmembrane helix–helix interactions, helix arrangements in membrane models, and testing their stability with molecular dynamics simulations. We also demonstrate the usage of the computational methods listed above by proposing a model for the molecular structure of the transmembrane protein bilitranslocase. Bilitranslocase is bilirubin membrane transporter, which shares similar tissue distribution and functional properties with some of the members of the Organic Anion Transporter family and is the only member classified in the Bilirubin Transporter Family. Regarding its unique properties, bilitranslocase is a potentially interesting drug target.
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Affiliation(s)
- Katja Venko
- Department of Cheminformatics, National Institute of Chemistry, Ljubljana, Slovenia
| | - A Roy Choudhury
- Department of Cheminformatics, National Institute of Chemistry, Ljubljana, Slovenia
| | - Marjana Novič
- Department of Cheminformatics, National Institute of Chemistry, Ljubljana, Slovenia
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42
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Logger L, Zoued A, Cascales E. Fusion Reporter Approaches to Monitoring Transmembrane Helix Interactions in Bacterial Membranes. Methods Mol Biol 2017; 1615:199-210. [PMID: 28667614 DOI: 10.1007/978-1-4939-7033-9_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
In transenvelope multiprotein machines such as bacterial secretion systems, protein-protein interactions not only occur between soluble domains but might also be mediated by helix-helix contacts in the inner membrane. Here we describe genetic assays commonly used to test interactions between transmembrane α-helices in their native membrane environment. These assays are based on the reconstitution of dimeric regulators allowing the control of expression of reporter genes. We provide detailed protocols for the TOXCAT and GALLEX assays used to monitor homotypic and heterotypic transmembrane helix-helix interactions.
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Affiliation(s)
- Laureen Logger
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ-CNRS, 31 Chemin Joseph Aiguier, 13402, Marseille Cedex 20, France
| | - Abdelrahim Zoued
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ-CNRS, 31 Chemin Joseph Aiguier, 13402, Marseille Cedex 20, France.,Division of Infectious Diseases and Harvard Medical School, Department of Microbiology and Immunobiology, Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA, USA
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ-CNRS, 31 Chemin Joseph Aiguier, 13402, Marseille Cedex 20, France.
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Del Piccolo N, Sarabipour S, Hristova K. A New Method to Study Heterodimerization of Membrane Proteins and Its Application to Fibroblast Growth Factor Receptors. J Biol Chem 2016; 292:1288-1301. [PMID: 27927983 DOI: 10.1074/jbc.m116.755777] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 12/05/2016] [Indexed: 12/30/2022] Open
Abstract
The activity of receptor tyrosine kinases (RTKs) is controlled through their lateral association in the plasma membrane. RTKs are believed to form both homodimers and heterodimers, and the different dimers are believed to play unique roles in cell signaling. However, RTK heterodimers remain poorly characterized, as compared with homodimers, because of limitations in current experimental methods. Here, we develop a FRET-based methodology to assess the thermodynamics of hetero-interactions in the plasma membrane. To demonstrate the utility of the methodology, we use it to study the hetero-interactions between three fibroblast growth factor receptors-FGFR1, FGFR2, and FGFR3-in the absence of ligand. Our results show that all possible FGFR heterodimers form, suggesting that the biological roles of FGFR heterodimers may be as significant as the homodimer roles. We further investigate the effect of two pathogenic point mutations in FGFR3 (A391E and G380R) on heterodimerization. We show that each of these mutations stabilize most of the heterodimers, with the largest effects observed for FGFR3 wild-type/mutant heterodimers. We thus demonstrate that the methodology presented here can yield new knowledge about RTK interactions and can further our understanding of signal transduction across the plasma membrane.
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Affiliation(s)
- Nuala Del Piccolo
- From the Department of Materials Science & Engineering, The Johns Hopkins University, Baltimore, Maryland 21218
| | - Sarvenaz Sarabipour
- From the Department of Materials Science & Engineering, The Johns Hopkins University, Baltimore, Maryland 21218
| | - Kalina Hristova
- From the Department of Materials Science & Engineering, The Johns Hopkins University, Baltimore, Maryland 21218
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44
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Klug YA, Rotem E, Schwarzer R, Shai Y. Mapping out the intricate relationship of the HIV envelope protein and the membrane environment. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:550-560. [PMID: 27793589 DOI: 10.1016/j.bbamem.2016.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 01/08/2023]
Abstract
The HIV gp160 envelope fusion protein is situated in the viral membrane and mediates virus entry into its host cell. Increasing evidence suggests that virtually all parts of the HIV envelope are structurally and functionally dependent on membranes. Protein-lipid interactions and membrane properties influence the dynamics of a manifold of gp160 biological activities such as membrane fusion, immune suppression and gp160 incorporation into virions during HIV budding and assembly. In the following we will summarize our current understanding of this interdependence between membrane interaction, structural conformation and functionality of the different gp160 domains. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider.
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Affiliation(s)
- Yoel A Klug
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Etai Rotem
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Roland Schwarzer
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Yechiel Shai
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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45
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Nadezhdin KD, García-Carpio I, Goncharuk SA, Mineev KS, Arseniev AS, Vilar M. Structural Basis of p75 Transmembrane Domain Dimerization. J Biol Chem 2016; 291:12346-57. [PMID: 27056327 DOI: 10.1074/jbc.m116.723585] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Indexed: 12/14/2022] Open
Abstract
Dimerization of single span transmembrane receptors underlies their mechanism of activation. p75 neurotrophin receptor plays an important role in the nervous system, but the understanding of p75 activation mechanism is still incomplete. The transmembrane (TM) domain of p75 stabilizes the receptor dimers through a disulfide bond, essential for the NGF signaling. Here we solved by NMR the three-dimensional structure of the p75-TM-WT and the functionally inactive p75-TM-C257A dimers. Upon reconstitution in lipid micelles, p75-TM-WT forms the disulfide-linked dimers spontaneously. Under reducing conditions, p75-TM-WT is in a monomer-dimer equilibrium with the Cys(257) residue located on the dimer interface. In contrast, p75-TM-C257A forms dimers through the AXXXG motif on the opposite face of the α-helix. Biochemical and cross-linking experiments indicate that AXXXG motif is not on the dimer interface of p75-TM-WT, suggesting that the conformation of p75-TM-C257A may be not functionally relevant. However, rather than mediating p75 homodimerization, mutagenesis of the AXXXG motif reveals its functional role in the regulated intramembrane proteolysis of p75 catalyzed by the γ-secretase complex. Our structural data provide an insight into the key role of the Cys(257) in stabilization of the weak transmembrane dimer in a conformation required for the NGF signaling.
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Affiliation(s)
- Kirill D Nadezhdin
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow 117997, Russian Federation and
| | - Irmina García-Carpio
- Neurodegeneration Unit, Unidad Funcional de Investigación de Enfermedades Crónicas-Instituto de Salud Carlos III, Crta Majadahonda a Pozuelo km.2 Majadahonda, Madrid 28220, Spain
| | - Sergey A Goncharuk
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow 117997, Russian Federation and
| | - Konstantin S Mineev
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow 117997, Russian Federation and
| | - Alexander S Arseniev
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow 117997, Russian Federation and
| | - Marçal Vilar
- Neurodegeneration Unit, Unidad Funcional de Investigación de Enfermedades Crónicas-Instituto de Salud Carlos III, Crta Majadahonda a Pozuelo km.2 Majadahonda, Madrid 28220, Spain
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46
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Rotem E, Reuven EM, Klug YA, Shai Y. The Transmembrane Domain of HIV-1 gp41 Inhibits T-Cell Activation by Targeting Multiple T-Cell Receptor Complex Components through Its GxxxG Motif. Biochemistry 2016; 55:1049-57. [PMID: 26828096 DOI: 10.1021/acs.biochem.5b01307] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
To successfully infect and persist within its host, HIV-1 utilizes several immunosuppressive motifs within its gp41 envelope glycoprotein to manipulate and evade the immune system. The transmembrane domain (TMD) of gp41 downregulates T-cell receptor (TCR) signaling through a hitherto unknown mechanism. Interactions between TMDs within the membrane milieu have been shown to be typically mediated by particular amino acids, such as interactions between basic and acidic residues and dimerization motifs as GxxxG. The HIV-1 TMD exhibits both a polar arginine (Arg(696)) residue and a GxxxG motif, making them ideal candidates for mediators of TMD-TCR interaction. Using a primary T-cell activation assay and biochemical and biophysical methods, we demonstrate that the gp41 TMD directly interacts with TMDs of the TCR and the CD3 coreceptors (δ, γ, and ε) within the membrane, presumably leading to impairment of complex assembly. Additionally, we reveal that although Arg(696) does not affect TMD immunosuppression, the GxxxG motif is crucial in mediating gp41's TMD interaction with the CD3 coreceptors of the TCR. These findings suggest that compared with other gp41 immunosuppressive motifs, the gp41 TMD has multiple targets within the TCR complex, suggesting less susceptibility to evolutionary pressure and consequently being advantageous for the virus over the host immune response. Furthermore, as the GxxxG motif mediates interactions of the gp41 TMD with multiple receptors, it emerges as an attractive drug target. This multitarget inhibitory mechanism might be a strategy utilized by HIV to interfere with the function of additional host receptors.
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Affiliation(s)
- Etai Rotem
- Department of Biological Chemistry, The Weizmann Institute of Science , Rehovot 76100, Israel
| | - Eliran Moshe Reuven
- Department of Biological Chemistry, The Weizmann Institute of Science , Rehovot 76100, Israel
| | - Yoel A Klug
- Department of Biological Chemistry, The Weizmann Institute of Science , Rehovot 76100, Israel
| | - Yechiel Shai
- Department of Biological Chemistry, The Weizmann Institute of Science , Rehovot 76100, Israel
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47
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Abstract
The majority of therapeutics target membrane proteins, accessible on the surface of cells, to alter cellular signaling. Cells use membrane proteins to transduce signals into cells, transport ions and molecules, bind cells to a surface or substrate, and catalyze reactions. Newly devised technologies allow us to drug conventionally "undruggable" regions of membrane proteins, enabling modulation of protein-protein, protein-lipid, and protein-nucleic acid interactions. In this review, we survey the state of the art of high-throughput screening and rational design in drug discovery, and we evaluate the advances in biological understanding and technological capacity that will drive pharmacotherapy forward against unorthodox membrane protein targets.
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Affiliation(s)
- Hang Yin
- Department of Chemistry and Biochemistry.,BioFrontiers Institute, and.,Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing 100082, China
| | - Aaron D Flynn
- BioFrontiers Institute, and.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309; ,
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48
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Li Y, Liew LSY, Li Q, Kang C. Structure of the transmembrane domain of human nicastrin-a component of γ-secretase. Sci Rep 2016; 6:19522. [PMID: 26776682 PMCID: PMC4726005 DOI: 10.1038/srep19522] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/09/2015] [Indexed: 02/04/2023] Open
Abstract
Nicastrin is the largest component of γ-secretase that is an intramembrane protease important in the development of Alzheimer's disease. Nicastrin contains a large extracellular domain, a single transmembrane (TM) domain, and a short C-terminus. Its TM domain is important for the γ-secretase complex formation. Here we report nuclear magnetic resonance (NMR) studies of the TM and C-terminal regions of human nicastrin in both sodium dodecyl sulfate (SDS) and dodecylphosphocholine (DPC) micelles. Structural study and dynamic analysis reveal that the TM domain is largely helical and stable under both SDS and DPC micelles with its N-terminal region undergoing intermediate time scale motion. The TM helix contains a hydrophilic patch that is important for TM-TM interactions. The short C-terminus is not structured in solution and a region formed by residues V697-A702 interacts with the membrane, suggesting that these residues may play a role in the γ-secretase complex formation. Our study provides structural insight into the function of the nicastrin TM domain and the C-terminus in γ-secretase complex.
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Affiliation(s)
- Yan Li
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, 138669 Singapore
| | - Lynette Sin Yee Liew
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, 138669 Singapore
| | - Qingxin Li
- Institute of Chemical &Engineering Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, 138669 Singapore
| | - CongBao Kang
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, 138669 Singapore
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49
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Bi G, Liebrand TWH, Bye RR, Postma J, van der Burgh AM, Robatzek S, Xu X, Joosten MHAJ. SOBIR1 requires the GxxxG dimerization motif in its transmembrane domain to form constitutive complexes with receptor-like proteins. MOLECULAR PLANT PATHOLOGY 2016; 17:96-107. [PMID: 25891985 PMCID: PMC6638328 DOI: 10.1111/mpp.12266] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Receptor-like proteins (RLPs), forming an important group of transmembrane receptors in plants, play roles in development and immunity. RLPs contain extracellular leucine-rich repeats (LRRs) and, in contrast with receptor-like kinases (RLKs), lack a cytoplasmic kinase required for the initiation of downstream signalling. Recent studies have revealed that the RLK SOBIR1/EVR (SUPPRESSOR OF BIR1-1/EVERSHED) specifically interacts with RLPs. SOBIR1 stabilizes RLPs and is required for their function. However, the mechanism by which SOBIR1 associates with RLPs and regulates RLP function remains unknown. The Cf immune receptors of tomato (Solanum lycopersicum), mediating resistance to the fungus Cladosporium fulvum, are RLPs that also interact with SOBIR1. Here, we show that both the LRR and kinase domain of SOBIR1 are dispensable for association with the RLP Cf-4, whereas the highly conserved GxxxGxxxG motif present in the transmembrane domain of SOBIR1 is essential for its interaction with Cf-4 and additional RLPs. Complementation assays in Nicotiana benthamiana, in which endogenous SOBIR1 levels were knocked down by virus-induced gene silencing, showed that the LRR domain as well as the kinase activity of SOBIR1 are required for the Cf-4/Avr4-triggered hypersensitive response (HR). In contrast, the LRRs and kinase activity of SOBIR1 are not required for facilitation of Cf-4 accumulation. Together, these results suggest that, in addition to being a stabilizing scaffold for RLPs, SOBIR1 is also required for the initiation of downstream signalling through its kinase domain.
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Affiliation(s)
- Guozhi Bi
- College of Horticulture, Northeast Agricultural University, Harbin, 150030, China
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Thomas W H Liebrand
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Ruby R Bye
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Jelle Postma
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Aranka M van der Burgh
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Silke Robatzek
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Xiangyang Xu
- College of Horticulture, Northeast Agricultural University, Harbin, 150030, China
| | - Matthieu H A J Joosten
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
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50
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Holme RL, Miller JJ, Nicholson K, Sahoo D. Tryptophan 415 Is Critical for the Cholesterol Transport Functions of Scavenger Receptor BI. Biochemistry 2015; 55:103-13. [PMID: 26652912 DOI: 10.1021/acs.biochem.5b00804] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High density lipoproteins (HDL) are anti-atherogenic particles, primarily due to their role in the reverse cholesterol transport pathway whereby HDL delivers cholesteryl esters (CE) to the liver for excretion upon interaction with its receptor, scavenger receptor BI (SR-BI). We designed experiments to test the hypothesis that one or more of the eight highly conserved tryptophan (Trp; W) residues in SR-BI are critical for mediating function. We created a series of Trp-to-phenylalanine (Phe, F) mutant receptors, as well as Trp-less SR-BI (ΔW-SR-BI), and assessed their ability to mediate cholesterol transport. Wild-type (WT) or mutant SR-BI receptors were transiently expressed in COS-7 cells, and cell surface expression was confirmed. Next, we showed that Trp-less- and W415F-SR-BI had significantly decreased abilities to bind HDL and promote selective uptake of HDL-CE, albeit with higher selective uptake efficiency as compared to WT-SR-BI. Interestingly, only Trp-less-, but not W415F-SR-BI, showed an impaired ability to mediate efflux of free cholesterol (FC). Furthermore, both W415F- and Trp-less-SR-BI were unable to reorganize plasma membrane pools of FC based on lack of sensitivity to exogenous cholesterol oxidase. Restoration of Trp 415 into the Trp-less-SR-BI background was unable to rescue Trp-less-SR-BI's impaired functions, suggesting that Trp 415 is critical, but not sufficient for full receptor function. Furthermore, with the exception of Trp 262, restoration of individual extracellular Trp residues, in combination with Trp 415, into the Trp-less-SR-BI background partially rescued SR-BI function, indicating that Trp 415 must be present in combination with other Trp residues for proper cholesterol transport functions.
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Affiliation(s)
- Rebecca L Holme
- Department of Biochemistry, Medical College of Wisconsin , Milwaukee, Wisconsin, United States
| | - James J Miller
- Department of Biochemistry, Medical College of Wisconsin , Milwaukee, Wisconsin, United States
| | - Kay Nicholson
- Department of Medicine, Division of Endocrinology, Metabolism & Clinical Nutrition, Medical College of Wisconsin , Milwaukee, Wisconsin, United States
| | - Daisy Sahoo
- Department of Medicine, Division of Endocrinology, Metabolism & Clinical Nutrition, Medical College of Wisconsin , Milwaukee, Wisconsin, United States.,Department of Biochemistry, Medical College of Wisconsin , Milwaukee, Wisconsin, United States.,Cardiovascular Center, Medical College of Wisconsin , Milwaukee, Wisconsin, United States
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