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Matthews CEP, Fussner LA, Yaeger M, Aloor JJ, Reece SW, Kilburg-Basnyat BJ, Varikuti S, Luo B, Inks M, Sergin S, Schmidt CA, Neufer PD, Pennington ER, Fisher-Wellman KH, Chowdhury SM, Fessler MB, Fenton JI, Anderson EJ, Shaikh SR, Gowdy KM. The prohibitin complex regulates macrophage fatty acid composition, plasma membrane packing, and lipid raft-mediated inflammatory signaling. Prostaglandins Leukot Essent Fatty Acids 2023; 190:102540. [PMID: 36706677 PMCID: PMC9992117 DOI: 10.1016/j.plefa.2023.102540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/28/2022] [Accepted: 01/15/2023] [Indexed: 01/20/2023]
Abstract
Prohibitins (PHB1 and PHB2) are ubiquitously expressed proteins which play critical roles in multiple biological processes, and together form the ring-like PHB complex found in phospholipid-rich cellular compartments including lipid rafts. Recent studies have implicated PHB1 as a mediator of fatty acid transport as well as a membrane scaffold mediating B lymphocyte and mast cell signal transduction. However, the specific role of PHBs in the macrophage have not been characterized, including their role in fatty acid uptake and lipid raft-mediated inflammatory signaling. We hypothesized that the PHB complex regulates macrophage inflammatory signaling through the formation of lipid rafts. To evaluate our hypothesis, RAW 264.7 macrophages were transduced with shRNA against PHB1, PHB2, or scrambled control (Scr), and then stimulated with lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF-α), which activate lipid raft-dependent receptor signaling (CD14/TLR4 and TNFR1, respectively). PHB1 knockdown was lethal, whereas PHB2 knockdown (PHB2kd), which also resulted in decreased PHB1 expression, led to attenuated nuclear factor-kappa-B (NF-κB) activation and subsequent cytokine and chemokine production. PHB2kd macrophages also had decreased cell surface TNFR1, CD14, TLR4, and lipid raft marker ganglioside GM1 at baseline and post-stimuli. Post-LPS, PHB2kd macrophages did not increase the concentration of cellular saturated, monounsaturated, and polyunsaturated fatty acids. This was accompanied by decreased lipid raft formation and modified plasma membrane molecular packing, further supporting the PHB complex's importance in lipid raft formation. Taken together, these data suggest a critical role for PHBs in regulating macrophage inflammatory signaling via maintenance of fatty acid composition and lipid raft structure. SUMMARY: Prohibitins are proteins found in phospholipid-rich cellular compartments, including lipid rafts, that play important roles in signaling, transcription, and multiple other cell functions. Macrophages are key cells in the innate immune response and the presence of membrane lipid rafts is integral to signal transduction, but the role of prohibitins in macrophage lipid rafts and associated signaling is unknown. To address this question, prohibitin knockdown macrophages were generated and responses to lipopolysaccharide and tumor necrosis factor-alpha, which act through lipid raft-dependent receptors, were analyzed. Prohibitin knockdown macrophages had significantly decreased cytokine and chemokine production, transcription factor activation, receptor expression, lipid raft assembly and membrane packing, and altered fatty acid remodeling. These data indicate a novel role for prohibitins in macrophage inflammatory signaling through regulation of fatty acid composition and lipid raft formation.
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Affiliation(s)
- Christine E Psaltis Matthews
- Department of Pharmacology and Toxicology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Lynn A Fussner
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Michael Yaeger
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Jim J Aloor
- Diabetes and Obesity Institute, Department of Physiology, East Carolina University, Greenville, NC, United States
| | - Sky W Reece
- Department of Pharmacology and Toxicology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Brita J Kilburg-Basnyat
- Department of Pharmacology and Toxicology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Sanjay Varikuti
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Bin Luo
- Department of Pharmacology and Toxicology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Morgan Inks
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Selin Sergin
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI, United States
| | - Cameron A Schmidt
- Diabetes and Obesity Institute, Department of Physiology, East Carolina University, Greenville, NC, United States
| | - P Darrell Neufer
- Diabetes and Obesity Institute, Department of Physiology, East Carolina University, Greenville, NC, United States
| | - Edward Ross Pennington
- Department of Nutrition, Gillings School of Global Public Health and School of Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - Kelsey H Fisher-Wellman
- Diabetes and Obesity Institute, Department of Physiology, East Carolina University, Greenville, NC, United States
| | - Saiful M Chowdhury
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, United States
| | - Michael B Fessler
- Immunity, Inflammation and Disease Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, United States
| | - Jenifer I Fenton
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI, United States
| | - Ethan J Anderson
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, FOE Diabetes Research Center, University of Iowa, Iowa City, IA, United States
| | - Saame Raza Shaikh
- Department of Nutrition, Gillings School of Global Public Health and School of Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - Kymberly M Gowdy
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States.
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Hussain S, Johnson CG, Sciurba J, Meng X, Stober VP, Liu C, Cyphert-Daly JM, Bulek K, Qian W, Solis A, Sakamachi Y, Trempus CS, Aloor JJ, Gowdy KM, Foster WM, Hollingsworth JW, Tighe RM, Li X, Fessler MB, Garantziotis S. TLR5 participates in the TLR4 receptor complex and promotes MyD88-dependent signaling in environmental lung injury. eLife 2020; 9:e50458. [PMID: 31989925 PMCID: PMC7032926 DOI: 10.7554/elife.50458] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 01/24/2020] [Indexed: 12/21/2022] Open
Abstract
Lung disease causes significant morbidity and mortality, and is exacerbated by environmental injury, for example through lipopolysaccharide (LPS) or ozone (O3). Toll-like receptors (TLRs) orchestrate immune responses to injury by recognizing pathogen- or danger-associated molecular patterns. TLR4, the prototypic receptor for LPS, also mediates inflammation after O3, triggered by endogenous hyaluronan. Regulation of TLR4 signaling is incompletely understood. TLR5, the flagellin receptor, is expressed in alveolar macrophages, and regulates immune responses to environmental injury. Using in vivo animal models of TLR4-mediated inflammations (LPS, O3, hyaluronan), we show that TLR5 impacts the in vivo response to LPS, hyaluronan and O3. We demonstrate that immune cells of human carriers of a dominant negative TLR5 allele have decreased inflammatory response to O3 exposure ex vivo and LPS exposure in vitro. Using primary murine macrophages, we find that TLR5 physically associates with TLR4 and biases TLR4 signaling towards the MyD88 pathway. Our results suggest an updated paradigm for TLR4/TLR5 signaling.
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Affiliation(s)
- Salik Hussain
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
- Department of Physiology and Pharmacology, School of MedicineWest Virginia UniversityMorgantownUnited States
| | - Collin G Johnson
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
- Center for Cell and Gene TherapyBaylor College of MedicineHoustonUnited States
| | - Joseph Sciurba
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
- Department of Veterinary MedicineNorth Carolina State UniversityRaleighUnited States
| | - Xianglin Meng
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
- Department of ICUFirst Affiliated Hospital of Harbin Medical UniversityHarbinChina
| | - Vandy P Stober
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
| | - Caini Liu
- Lerner Research Institute, Cleveland Clinic FoundationClevelandUnited States
| | - Jaime M Cyphert-Daly
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
- Duke University Medical CenterDurhamUnited States
| | - Katarzyna Bulek
- Lerner Research Institute, Cleveland Clinic FoundationClevelandUnited States
- Department of Immunology, Faculty of Biochemistry, Biophysics and BiotechnologyJagiellonian UniversityKrakowPoland
| | - Wen Qian
- Lerner Research Institute, Cleveland Clinic FoundationClevelandUnited States
| | - Alma Solis
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
| | - Yosuke Sakamachi
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
| | - Carol S Trempus
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
| | - Jim J Aloor
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
- East Carolina University Brody School of MedicineGreenvilleUnited States
| | - Kym M Gowdy
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
- East Carolina University Brody School of MedicineGreenvilleUnited States
| | | | | | | | - Xiaoxia Li
- Lerner Research Institute, Cleveland Clinic FoundationClevelandUnited States
| | - Michael B Fessler
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
| | - Stavros Garantziotis
- National Institute of Environmental Health SciencesResearch Triangle ParkUnited States
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3
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Kamal AHM, Aloor JJ, Fessler MB, Chowdhury SM. Cross-linking Proteomics Indicates Effects of Simvastatin on the TLR2 Interactome and Reveals ACTR1A as a Novel Regulator of the TLR2 Signal Cascade. Mol Cell Proteomics 2019; 18:1732-1744. [PMID: 31221720 PMCID: PMC6731082 DOI: 10.1074/mcp.ra119.001377] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/25/2019] [Indexed: 01/23/2023] Open
Abstract
Toll-like receptor 2 (TLR2) is a pattern recognition receptor that, upon ligation by microbial molecules, interacts with other proteins to initiate pro-inflammatory responses by the cell. Statins (hydroxymethylglutaryl coenzyme A reductase inhibitors), drugs widely prescribed to reduce hypercholesterolemia, are reported to have both pro- and anti-inflammatory effects upon cells. Some of these responses are presumed to be driven by effects on signaling proteins at the plasma membrane, but the underlying mechanisms remain obscure. We reasoned that profiling the effect of statins on the repertoire of TLR2-interacting proteins might provide novel insights into the mechanisms by which statins impact inflammation. In order to study the TLR2 interactome, we designed a coimmunoprecipitation (IP)-based cross-linking proteomics study. A hemagglutinin (HA)-tagged-TLR2 transfected HEK293 cell line was used to precipitate the TLR2 interactome upon cell exposure to the TLR2 agonist Pam3CSK4 and simvastatin, singly and in combination. To stabilize protein interactors, we used two different chemical cross-linkers with different spacer chain lengths. Proteomic analysis revealed important combinatorial effects of simvastatin and Pam3CSK4 on the TLR2 interactome. After stringent data filtering, we identified alpha-centractin (ACTR1A), an actin-related protein and subunit of the dynactin complex, as a potential interactor of TLR2. The interaction was validated using biochemical methods. RNA interference studies revealed an important role for ACTR1A in induction of pro-inflammatory cytokines. Taken together, we report that statins remodel the TLR2 interactome, and we identify ACTR1A, a part of the dynactin complex, as a novel regulator of TLR2-mediated immune signaling pathways.
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Affiliation(s)
- Abu Hena Mostafa Kamal
- ‡Department of Chemistry and Biochemistry, University of Texas at Arlington, Texas 76019
| | - Jim J Aloor
- §Immunity, Inflammation and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Michael B Fessler
- §Immunity, Inflammation and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Saiful M Chowdhury
- ‡Department of Chemistry and Biochemistry, University of Texas at Arlington, Texas 76019.
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Aloor JJ, Azzam KM, Guardiola JJ, Gowdy KM, Madenspacher JH, Gabor KA, Mueller GA, Lin WC, Lowe JM, Gruzdev A, Henderson MW, Draper DW, Merrick BA, Fessler MB. Leucine-rich repeats and calponin homology containing 4 (Lrch4) regulates the innate immune response. J Biol Chem 2018; 294:1997-2008. [PMID: 30523158 DOI: 10.1074/jbc.ra118.004300] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 11/27/2018] [Indexed: 01/07/2023] Open
Abstract
Toll-like receptors (TLRs) are pathogen-recognition receptors that trigger the innate immune response. Recent reports have identified accessory proteins that provide essential support to TLR function through ligand delivery and receptor trafficking. Herein, we introduce leucine-rich repeats (LRRs) and calponin homology containing 4 (Lrch4) as a novel TLR accessory protein. Lrch4 is a membrane protein with nine LRRs in its predicted ectodomain. It is widely expressed across murine tissues and has two expression variants that are both regulated by lipopolysaccharide (LPS). Predictive modeling indicates that Lrch4 LRRs conform to the horseshoe-shaped structure typical of LRRs in pathogen-recognition receptors and that the best structural match in the protein database is to the variable lymphocyte receptor of the jawless vertebrate hagfish. Silencing Lrch4 attenuates cytokine induction by LPS and multiple other TLR ligands and dampens the in vivo innate immune response. Lrch4 promotes proper docking of LPS in lipid raft membrane microdomains. We provide evidence that this is through regulation of lipid rafts as Lrch4 silencing reduces cell surface gangliosides, a metric of raft abundance, as well as expression and surface display of CD14, a raft-resident LPS co-receptor. Taken together, we identify Lrch4 as a broad-spanning regulator of the innate immune response and a potential molecular target in inflammatory disease.
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Affiliation(s)
- Jim J Aloor
- From the Immunity, Inflammation and Disease Laboratory
| | | | | | | | | | | | | | - Wan-Chi Lin
- From the Immunity, Inflammation and Disease Laboratory
| | - Julie M Lowe
- From the Immunity, Inflammation and Disease Laboratory
| | | | | | | | - B Alex Merrick
- National Toxicology Program, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
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5
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Henderson MW, Madenspacher JH, Whitehead GS, Thomas SY, Aloor JJ, Gowdy KM, Fessler MB. Effects of Orally Ingested Arsenic on Respiratory Epithelial Permeability to Bacteria and Small Molecules in Mice. Environ Health Perspect 2017; 125:097024. [PMID: 28960179 PMCID: PMC5915208 DOI: 10.1289/ehp1878] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 05/27/2023]
Abstract
BACKGROUND Arsenic exposure via drinking water impacts millions of people worldwide. Although arsenic has been associated epidemiologically with increased lung infections, the identity of the lung cell types targeted by peroral arsenic and the associated immune mechanisms remain poorly defined. OBJECTIVES We aimed to determine the impact of peroral arsenic on pulmonary antibacterial host defense. METHODS Female C57BL/6 mice were administered drinking water with 0, 250 ppb, or 25 ppm sodium arsenite for 5 wk and then challenged intratracheally with Klebsiella pneumoniae, Streptococcus pneumoniae, or lipopolysaccharide. Bacterial clearance and immune responses were profiled. RESULTS Arsenic had no effect on bacterial clearance in the lung or on the intrapulmonary innate immune response to bacteria or lipopolysaccharide, as assessed by neutrophil recruitment to, and cytokine induction in, the airspace. Alveolar macrophage TNFα production was unaltered. By contrast, arsenic-exposed mice had significantly reduced plasma TNFα in response to systemic lipopolysaccharide challenge, together suggesting that the local airway innate immune response may be relatively preserved from arsenic intoxication. Despite intact intrapulmonary bacterial clearance during pneumonia, arsenic-exposed mice suffered dramatically increased bacterial dissemination to the bloodstream. Mechanistically, this was linked to increased respiratory epithelial permeability, as revealed by intratracheal FITC-dextran tracking, serum Club Cell protein 16 measurement, and other approaches. Consistent with barrier disruption at the alveolar level, arsenic-exposed mice had evidence for alveolar epithelial type 1 cell injury. CONCLUSIONS Peroral arsenic has little effect on local airway immune responses to bacteria but compromises respiratory epithelial barrier integrity, increasing systemic translocation of inhaled pathogens and small molecules. https://doi.org/10.1289/EHP1878.
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Affiliation(s)
- Michael W Henderson
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services , Research Triangle Park, North Carolina, USA
| | - Jennifer H Madenspacher
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services , Research Triangle Park, North Carolina, USA
| | - Gregory S Whitehead
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services , Research Triangle Park, North Carolina, USA
| | - Seddon Y Thomas
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services , Research Triangle Park, North Carolina, USA
| | - Jim J Aloor
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services , Research Triangle Park, North Carolina, USA
| | - Kymberly M Gowdy
- Department of Pharmacology and Toxicology, Brody School of Medicine, East Carolina University , Greenville, North Carolina, USA
| | - Michael B Fessler
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services , Research Triangle Park, North Carolina, USA
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6
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Lai L, Azzam KM, Lin WC, Rai P, Lowe JM, Gabor KA, Madenspacher JH, Aloor JJ, Parks JS, Näär AM, Fessler MB. MicroRNA-33 Regulates the Innate Immune Response via ATP Binding Cassette Transporter-mediated Remodeling of Membrane Microdomains. J Biol Chem 2016; 291:19651-60. [PMID: 27471270 DOI: 10.1074/jbc.m116.723056] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Indexed: 01/07/2023] Open
Abstract
MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression by promoting degradation and/or repressing translation of specific target mRNAs. Several miRNAs have been identified that regulate the amplitude of the innate immune response by directly targeting Toll-like receptor (TLR) pathway members and/or cytokines. miR-33a and miR-33b (the latter present in primates but absent in rodents and lower species) are located in introns of the sterol regulatory element-binding protein (SREBP)-encoding genes and control cholesterol/lipid homeostasis in concert with their host gene products. These miRNAs regulate macrophage cholesterol by targeting the lipid efflux transporters ATP binding cassette (ABC)A1 and ABCG1. We and others have previously reported that Abca1(-/-) and Abcg1(-/-) macrophages have increased TLR proinflammatory responses due to augmented lipid raft cholesterol. Given this, we hypothesized that miR-33 would augment TLR signaling in macrophages via a raft cholesterol-dependent mechanism. Herein, we report that multiple TLR ligands down-regulate miR-33 in murine macrophages. In the case of lipopolysaccharide, this is a delayed, Toll/interleukin-1 receptor (TIR) domain-containing adapter-inducing interferon-β-dependent response that also down-regulates Srebf-2, the host gene for miR-33. miR-33 augments macrophage lipid rafts and enhances proinflammatory cytokine induction and NF-κB activation by LPS. This occurs through an ABCA1- and ABCG1-dependent mechanism and is reversible by interventions upon raft cholesterol and by ABC transporter-inducing liver X receptor agonists. Taken together, these findings extend the purview of miR-33, identifying it as an indirect regulator of innate immunity that mediates bidirectional cross-talk between lipid homeostasis and inflammation.
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Affiliation(s)
- Lihua Lai
- From the Immunity, Inflammation and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Kathleen M Azzam
- From the Immunity, Inflammation and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Wan-Chi Lin
- From the Immunity, Inflammation and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Prashant Rai
- From the Immunity, Inflammation and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Julie M Lowe
- From the Immunity, Inflammation and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Kristin A Gabor
- From the Immunity, Inflammation and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Jennifer H Madenspacher
- From the Immunity, Inflammation and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Jim J Aloor
- From the Immunity, Inflammation and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - John S Parks
- Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
| | - Anders M Näär
- Massachusetts General Hospital Cancer Center, Charlestown, Massachusetts 02129, and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Michael B Fessler
- From the Immunity, Inflammation and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709,
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7
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Chowdhury SM, Zhu X, Aloor JJ, Azzam KM, Gabor KA, Ge W, Addo KA, Tomer KB, Parks JS, Fessler MB. Proteomic Analysis of ABCA1-Null Macrophages Reveals a Role for Stomatin-Like Protein-2 in Raft Composition and Toll-Like Receptor Signaling. Mol Cell Proteomics 2015; 14:1859-70. [PMID: 25910759 DOI: 10.1074/mcp.m114.045179] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Indexed: 11/06/2022] Open
Abstract
Lipid raft membrane microdomains organize signaling by many prototypical receptors, including the Toll-like receptors (TLRs) of the innate immune system. Raft-localization of proteins is widely thought to be regulated by raft cholesterol levels, but this is largely on the basis of studies that have manipulated cell cholesterol using crude and poorly specific chemical tools, such as β-cyclodextrins. To date, there has been no proteome-scale investigation of whether endogenous regulators of intracellular cholesterol trafficking, such as the ATP binding cassette (ABC)A1 lipid efflux transporter, regulate targeting of proteins to rafts. Abca1(-/-) macrophages have cholesterol-laden rafts that have been reported to contain increased levels of select proteins, including TLR4, the lipopolysaccharide receptor. Here, using quantitative proteomic profiling, we identified 383 proteins in raft isolates from Abca1(+/+) and Abca1(-/-) macrophages. ABCA1 deletion induced wide-ranging changes to the raft proteome. Remarkably, many of these changes were similar to those seen in Abca1(+/+) macrophages after lipopolysaccharide exposure. Stomatin-like protein (SLP)-2, a member of the stomatin-prohibitin-flotillin-HflK/C family of membrane scaffolding proteins, was robustly and specifically increased in Abca1(-/-) rafts. Pursuing SLP-2 function, we found that rafts of SLP-2-silenced macrophages had markedly abnormal composition. SLP-2 silencing did not compromise ABCA1-dependent cholesterol efflux but reduced macrophage responsiveness to multiple TLR ligands. This was associated with reduced raft levels of the TLR co-receptor, CD14, and defective lipopolysaccharide-induced recruitment of the common TLR adaptor, MyD88, to rafts. Taken together, we show that the lipid transporter ABCA1 regulates the protein repertoire of rafts and identify SLP-2 as an ABCA1-dependent regulator of raft composition and of the innate immune response.
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Affiliation(s)
| | - Xuewei Zhu
- ¶Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Jim J Aloor
- From the ‡Laboratory of Respiratory Biology and
| | | | | | - William Ge
- From the ‡Laboratory of Respiratory Biology and
| | | | - Kenneth B Tomer
- §Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709
| | - John S Parks
- ¶Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157
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8
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Gale SC, Gao L, Mikacenic C, Coyle SM, Rafaels N, Murray Dudenkov T, Madenspacher JH, Draper DW, Ge W, Aloor JJ, Azzam KM, Lai L, Blackshear PJ, Calvano SE, Barnes KC, Lowry SF, Corbett S, Wurfel MM, Fessler MB. APOε4 is associated with enhanced in vivo innate immune responses in human subjects. J Allergy Clin Immunol 2014; 134:127-34. [PMID: 24655576 DOI: 10.1016/j.jaci.2014.01.032] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 01/08/2014] [Accepted: 01/20/2014] [Indexed: 01/28/2023]
Abstract
BACKGROUND The genetic determinants of the human innate immune response are poorly understood. Apolipoprotein (Apo) E, a lipid-trafficking protein that affects inflammation, has well-described wild-type (ε3) and disease-associated (ε2 and ε4) alleles, but its connection to human innate immunity is undefined. OBJECTIVE We sought to define the relationship of APOε4 to the human innate immune response. METHODS We evaluated APOε4 in several functional models of the human innate immune response, including intravenous LPS challenge in human subjects, and assessed APOε4 association to organ injury in patients with severe sepsis, a disease driven by dysregulated innate immunity. RESULTS Whole blood from healthy APOε3/APOε4 volunteers induced higher cytokine levels on ex vivo stimulation with Toll-like receptor (TLR) 2, TLR4, or TLR5 ligands than blood from APOε3/APOε3 patients, whereas TLR7/8 responses were similar. This was associated with increased lipid rafts in APOε3/APOε4 monocytes. By contrast, APOε3/APOε3 and APOε3/APOε4 serum neutralized LPS equivalently and supported similar LPS responses in Apoe-deficient macrophages, arguing against a differential role for secretory APOE4 protein. After intravenous LPS, APOε3/APOε4 patients had higher hyperthermia and plasma TNF-α levels and earlier plasma IL-6 than APOε3/APOε3 patients. APOE4-targeted replacement mice displayed enhanced hypothermia, plasma cytokines, and hepatic injury and altered splenic lymphocyte apoptosis after systemic LPS compared with APOE3 counterparts. In a cohort of 828 patients with severe sepsis, APOε4 was associated with increased coagulation system failure among European American patients. CONCLUSIONS APOε4 is a determinant of the human innate immune response to multiple TLR ligands and associates with altered patterns of organ injury in human sepsis.
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Affiliation(s)
- Stephen C Gale
- Department of Surgery, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ
| | - Li Gao
- Department of Medicine, Johns Hopkins University, Baltimore, Md
| | | | - Susette M Coyle
- Department of Surgery, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ
| | | | | | - Jennifer H Madenspacher
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC
| | - David W Draper
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC
| | - William Ge
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC
| | - Jim J Aloor
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC
| | - Kathleen M Azzam
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC
| | - Lihua Lai
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC
| | - Perry J Blackshear
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC
| | - Steven E Calvano
- Department of Surgery, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ
| | | | - Stephen F Lowry
- Department of Surgery, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ
| | - Siobhan Corbett
- Department of Surgery, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ
| | - Mark M Wurfel
- Department of Medicine, University of Washington, Seattle, Wash
| | - Michael B Fessler
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC.
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Madenspacher JH, Azzam KM, Gowdy KM, Malcolm KC, Nick JA, Dixon D, Aloor JJ, Draper DW, Guardiola JJ, Shatz M, Menendez D, Lowe J, Lu J, Bushel P, Li L, Merrick BA, Resnick MA, Fessler MB. p53 integrates host defense and cell fate during bacterial pneumonia. J Biophys Biochem Cytol 2013. [DOI: 10.1083/jcb2014oia5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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10
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Madenspacher JH, Azzam KM, Gowdy KM, Malcolm KC, Nick JA, Dixon D, Aloor JJ, Draper DW, Guardiola JJ, Shatz M, Menendez D, Lowe J, Lu J, Bushel P, Li L, Merrick BA, Resnick MA, Fessler MB. p53 Integrates host defense and cell fate during bacterial pneumonia. ACTA ACUST UNITED AC 2013; 210:891-904. [PMID: 23630228 PMCID: PMC3646498 DOI: 10.1084/jem.20121674] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
p53 deletion augments neutrophil-mediated bacterial clearance in the lung at the expense of tissue homeostasis, leading to increased mortality. Cancer and infection are predominant causes of human mortality and derive, respectively, from inadequate genomic and host defenses against environmental agents. The transcription factor p53 plays a central role in human tumor suppression. Despite its expression in immune cells and broad responsiveness to stressors, it is virtually unknown whether p53 regulates host defense against infection. We report that the lungs of naive p53−/− mice display genome-wide induction of NF-κB response element–enriched proinflammatory genes, suggestive of type 1 immune priming. p53-null and p53 inhibitor–treated mice clear Gram-negative and -positive bacteria more effectively than controls after intrapulmonary infection. This is caused, at least in part, by cytokines produced by an expanded population of apoptosis-resistant, TLR-hyperresponsive alveolar macrophages that enhance airway neutrophilia. p53−/− neutrophils, in turn, display heightened phagocytosis, Nox-dependent oxidant generation, degranulation, and bacterial killing. p53 inhibition boosts bacterial killing by mouse neutrophils and oxidant generation by human neutrophils. Despite enhanced bacterial clearance, infected p53−/− mice suffer increased mortality associated with aggravated lung injury. p53 thus modulates host defense through regulating microbicidal function and fate of phagocytes, revealing a fundamental link between defense of genome and host during environmental insult.
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Affiliation(s)
- Jennifer H Madenspacher
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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11
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Merrick BA, Dhungana S, Williams JG, Aloor JJ, Peddada S, Tomer KB, Fessler MB. Proteomic profiling of S-acylated macrophage proteins identifies a role for palmitoylation in mitochondrial targeting of phospholipid scramblase 3. Mol Cell Proteomics 2011; 10:M110.006007. [PMID: 21785166 DOI: 10.1074/mcp.m110.006007] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
S-Palmitoylation, the reversible post-translational acylation of specific cysteine residues with the fatty acid palmitate, promotes the membrane tethering and subcellular localization of proteins in several biological pathways. Although inhibiting palmitoylation holds promise as a means for manipulating protein targeting, advances in the field have been hampered by limited understanding of palmitoylation enzymology and consensus motifs. In order to define the complement of S-acylated proteins in the macrophage, we treated RAW 264.7 macrophage membranes with hydroxylamine to cleave acyl thioesters, followed by biotinylation of newly exposed sulfhydryls and streptavidin-agarose affinity chromatography. Among proteins identified by LC-MS/MS, S-acylation status was established by spectral counting to assess enrichment under hydroxylamine versus mock treatment conditions. Of 1183 proteins identified in four independent experiments, 80 proteins were significant for S-acylation at false discovery rate = 0.05, and 101 significant at false discovery rate = 0.10. Candidate S-acylproteins were identified from several functional categories, including membrane trafficking, signaling, transporters, and receptors. Among these were 29 proteins previously biochemically confirmed as palmitoylated, 45 previously reported as putative S-acylproteins in proteomic screens, 24 not previously associated with palmitoylation, and three presumed false-positives. Nearly half of the candidates were previously identified by us in macrophage detergent-resistant membranes, suggesting that palmitoylation promotes lipid raft-localization of proteins in the macrophage. Among the candidate novel S-acylproteins was phospholipid scramblase 3 (Plscr3), a protein that regulates apoptosis through remodeling the mitochondrial membrane. Palmitoylation of Plscr3 was confirmed through (3)H-palmitate labeling. Moreover, site-directed mutagenesis of a cluster of five cysteines (Cys159-161-163-164-166) abolished palmitoylation, caused Plscr3 mislocalization from mitochondrion to nucleus, and reduced macrophage apoptosis in response to etoposide, together suggesting a role for palmitoylation at this site for mitochondrial targeting and pro-apoptotic function of Plscr3. Taken together, we propose that manipulation of protein palmitoylation carries great potential for intervention in macrophage biology via reprogramming of protein localization.
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Affiliation(s)
- B Alex Merrick
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
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12
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Smoak KA, Aloor JJ, Madenspacher J, Merrick BA, Collins JB, Zhu X, Cavigiolio G, Oda MN, Parks JS, Fessler MB. Myeloid differentiation primary response protein 88 couples reverse cholesterol transport to inflammation. Cell Metab 2010; 11:493-502. [PMID: 20519121 PMCID: PMC3091482 DOI: 10.1016/j.cmet.2010.04.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 02/03/2010] [Accepted: 04/05/2010] [Indexed: 02/06/2023]
Abstract
Crosstalk exists in mammalian cells between cholesterol trafficking and innate immune signaling. Apolipoprotein A-I (apoA-I), a serum apolipoprotein that induces antiatherogenic efflux of macrophage cholesterol, is widely described as anti-inflammatory because it neutralizes bacterial lipopolysaccharide. Conversely, lipopolysaccharide-induced inflammation is proatherogenic. However, whether innate immunity plays an endogenous, physiological role in host cholesterol homeostasis in the absence of infection is undetermined. We report that apoA-I signals in the macrophage through Toll-like receptor (TLR)2, TLR4, and CD14, utilizing myeloid differentiation primary response protein 88 (MyD88)-dependent and -independent pathways, to activate nuclear factor-kappaB and induce cytokines. MyD88 plays a critical role in reverse cholesterol transport in vitro and in vivo, in part through promoting ATP-binding cassette A1 transporter upregulation. Taken together, this work identifies apoA-I as an endogenous stimulus of innate immunity that couples cholesterol trafficking to inflammation through MyD88 and identifies innate immunity as a physiologic signal in cholesterol homeostasis.
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Affiliation(s)
- Kathleen A. Smoak
- Laboratory of Respiratory Biology, NIEHS, Research Triangle Park, NC 27709 U.S.A
| | - Jim J. Aloor
- Laboratory of Respiratory Biology, NIEHS, Research Triangle Park, NC 27709 U.S.A
| | | | - B. Alex Merrick
- Laboratory of Respiratory Biology, NIEHS, Research Triangle Park, NC 27709 U.S.A
| | | | - Xuewei Zhu
- Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, NC 27157 U.S.A
| | | | - Michael N. Oda
- Children's Hospital Oakland Research Institute, Oakland, CA 94609 U.S.A
| | - John S. Parks
- Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, NC 27157 U.S.A
| | - Michael B. Fessler
- Laboratory of Respiratory Biology, NIEHS, Research Triangle Park, NC 27709 U.S.A
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Mueller GA, Edwards LL, Aloor JJ, Fessler MB, Glesner J, Pomés A, Chapman MD, London RE, Pedersen LC. The structure of the dust mite allergen Der p 7 reveals similarities to innate immune proteins. J Allergy Clin Immunol 2010; 125:909-917.e4. [PMID: 20226507 DOI: 10.1016/j.jaci.2009.12.016] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 12/03/2009] [Accepted: 12/04/2009] [Indexed: 12/21/2022]
Abstract
BACKGROUND Sensitization to house dust mite allergens is strongly correlated with asthma. Der p 7 elicits strong IgE antibody and T-cell responses in patients with mite allergy. However, the structure and biological function of this important allergen are unknown. Allergen function might contribute to allergenicity, as shown for the protease activity of group 1 mite allergens and the interaction with the innate immune system by group 2 mite allergens. OBJECTIVE We sought to determine the crystal structure of Der p 7 and to investigate its biological function. METHODS X-ray crystallography was used to determine the Der p 7 structure. Nuclear magnetic resonance analysis and biochemical assays were used to examine the binding of Der p 7 to predicted ligands. RESULTS Der p 7 has an elongated structure, with two 4-stranded antiparallel beta-sheets that wrap around a long C-terminal helix. The fold of Der p 7 is similar to that of LPS-binding protein (LBP), which interacts with Toll-like receptors after binding LPS and other bacterially derived lipid ligands. Nuclear magnetic resonance and biochemical assays indicate that Der p 7 does not bind LPS but binds with weak affinity to the bacterial lipopeptide polymyxin B in the predicted binding site of Der p 7. CONCLUSIONS Der p 7 binds a bacterially derived lipid product, a common feature of some allergens. The finding that the group 7, as well as the group 2, mite allergens are structurally similar to different proteins in the Toll-like receptor pathway further strengthens the connections between dust mites, innate immunity, and allergy.
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Affiliation(s)
- Geoffrey A Mueller
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA.
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14
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Broxmeyer HE, Sehra S, Cooper S, Toney LM, Kusam S, Aloor JJ, Marchal CC, Dinauer MC, Dent AL. Aberrant regulation of hematopoiesis by T cells in BAZF-deficient mice. Mol Cell Biol 2007; 27:5275-85. [PMID: 17526724 PMCID: PMC1952080 DOI: 10.1128/mcb.01967-05] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The BAZF (BCL-6b) protein is highly similar to the BCL-6 transcriptional repressor. While BCL-6 has been characterized extensively, relatively little is known about the normal function of BAZF. In order to understand the physiological role of BAZF, we created BAZF-deficient mice. Unlike BCL-6-deficient mice, BAZF-deficient mice are healthy and normal in size. However, BAZF-deficient mice have a hematopoietic progenitor phenotype that is almost identical to that of BCL-6-deficient mice. Compared to wild-type mice, both BAZF-deficient and BCL-6-deficient mice have greatly reduced numbers of cycling hematopoietic progenitor cells (HPC) in the BM and greatly increased numbers of cycling HPC in the spleen. In contrast to HPC from wild-type mice, HPC from BAZF-deficient and BCL-6-deficient mice are resistant to chemokine-induced myelosuppression and do not show a synergistic growth response to granulocyte-macrophage colony-stimulating factor plus stem cell factor. Depletion of CD8 T cells in BAZF-deficient mice reverses several of the hematopoietic defects in these mice. Since both BAZF- and BCL-6-deficient mice have defects in CD8 T-cell differentiation, we hypothesize that both BCL-6 and BAZF regulate HPC homeostasis by an indirect pathway involving CD8 T cells.
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Affiliation(s)
- Hal E Broxmeyer
- Department of Microbiology and Immunology and The Walther Oncology Center, 950 W. Walnut St. R2 302, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Abstract
SecB is a cytosolic tetrameric chaperone in Escherichia coli, which maintains polypeptides, destined for export in a translocation competent state. The thermodynamics of unfolding of SecB was studied as a function of protein concentration, by using high sensitivity-differential scanning calorimetry and spectroscopic methods. The thermal unfolding of tetrameric SecB is reversible and can be well described as a two-state transition in which the folded tetramer is converted directly to unfolded monomers. Increasing the pH decreases the stability of the tetramer significantly, the T(m) changing from 341.3 K at pH 6.5 to 332.6 K at pH 9.5. The value of DeltaC(p) obtained from measurements of DeltaH(m) as a function of T(m) was 10.7 +/- 0.7 kcal mol(-1) K(-1). The value of DeltaC(p) is among the highest measured for a multimeric protein. At 298 K, pH 7.4, the DeltaG degrees (u) for the SecB tetramer is 27.9 +/- 2 kcal mol(-1). Denaturant-mediated unfolding of SecB was found to be irreversible. The reactivity of the four solvent-exposed free thiols in tetrameric SecB is salt dependent. The kinetics of reactivity suggests that these four cysteines are in close proximity to each other and that these residues on each monomer are in chemically identical environments. The thermodynamic data suggest that SecB is a stable, well-folded, and tightly packed tetramer and that substrate binding occurs at a surface site rather than at an interior cavity.
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Affiliation(s)
- V G Panse
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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