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The human batokine EPDR1 regulates β-cell metabolism and function. Mol Metab 2022; 66:101629. [PMID: 36343918 PMCID: PMC9663883 DOI: 10.1016/j.molmet.2022.101629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 10/14/2022] [Accepted: 11/01/2022] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE Ependymin-Related Protein 1 (EPDR1) was recently identified as a secreted human batokine regulating mitochondrial respiration linked to thermogenesis in brown fat. Despite that EPDR1 is expressed in human pancreatic β-cells and that glucose-stimulated mitochondrial metabolism is critical for stimulus-secretion coupling in β-cells, the role of EPDR1 in β-cell metabolism and function has not been investigated. METHODS EPDR1 mRNA levels in human pancreatic islets from non-diabetic (ND) and type 2 diabetes (T2D) subjects were assessed. Human islets, EndoC-βH1 and INS1 832/13 cells were transfected with scramble (control) and EPDR1 siRNAs (EPDR1-KD) or treated with human EPDR1 protein, and glucose-stimulated insulin secretion (GSIS) assessed by ELISA. Mitochondrial metabolism was investigated by extracellular flux analyzer, confocal microscopy and mass spectrometry-based metabolomics analysis. RESULTS EPDR1 mRNA expression was upregulated in human islets from T2D and obese donors and positively correlated to BMI of donors. In T2D donors, EPDR1 mRNA levels negatively correlated with HbA1c and positively correlated with GSIS. EPDR1 silencing in human islets and β-cell lines reduced GSIS whereas treatment with human EPDR1 protein increased GSIS. Epdr1 silencing in INS1 832/13 cells reduced glucose- and pyruvate- but not K+-stimulated insulin secretion. Metabolomics analysis in Epdr1-KD INS1 832/13 cells suggests diversion of glucose-derived pyruvate to lactate production and decreased malate-aspartate shuttle and the tricarboxylic acid (TCA) cycle activity. The glucose-stimulated rise in mitochondrial respiration and ATP/ADP-ratio was impaired in Epdr1-deficient cells. CONCLUSION These results suggests that to maintain glucose homeostasis in obese people, upregulation of EPDR1 may improve β-cell function via channelling glycolysis-derived pyruvate to the mitochondrial TCA cycle.
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Park JK, Park S. A Single Soaked Iridium (
IV
) Ion Observed in the Frog Ependymin‐Related Protein. B KOREAN CHEM SOC 2020. [DOI: 10.1002/bkcs.12080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jeong Kuk Park
- School of Systems Biomedical Science, Soongsil University Seoul 06978 South Korea
| | - SangYoun Park
- School of Systems Biomedical Science, Soongsil University Seoul 06978 South Korea
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Park JK, Kim KY, Sim YW, Kim YI, Kim JK, Lee C, Han J, Kim CU, Lee JE, Park S. Structures of three ependymin-related proteins suggest their function as a hydrophobic molecule binder. IUCRJ 2019; 6:729-739. [PMID: 31316816 PMCID: PMC6608618 DOI: 10.1107/s2052252519007668] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/27/2019] [Indexed: 06/10/2023]
Abstract
Ependymin was first discovered as a predominant protein in brain extracellular fluid in fish and was suggested to be involved in functions mostly related to learning and memory. Orthologous proteins to ependymin called ependymin-related proteins (EPDRs) have been found to exist in various tissues from sea urchins to humans, yet their functional role remains to be revealed. In this study, the structures of EPDR1 from frog, mouse and human were determined and analyzed. All of the EPDR1s fold into a dimer using a monomeric subunit that is mostly made up of two stacking antiparallel β-sheets with a curvature on one side, resulting in the formation of a deep hydrophobic pocket. All six of the cysteine residues in the monomeric subunit participate in the formation of three intramolecular disulfide bonds. Other interesting features of EPDR1 include two asparagine residues with glycosylation and a Ca2+-binding site. The EPDR1 fold is very similar to the folds of bacterial VioE and LolA/LolB, which also use a similar hydrophobic pocket for their respective functions as a hydrophobic substrate-binding enzyme and a lipoprotein carrier, respectively. A further fatty-acid binding assay using EPDR1 suggests that it indeed binds to fatty acids, presumably via this pocket. Additional interactome analysis of EPDR1 showed that EPDR1 interacts with insulin-like growth factor 2 receptor and flotillin proteins, which are known to be involved in protein and vesicle translocation.
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Affiliation(s)
- Jeong Kuk Park
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea
| | - Keon Young Kim
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea
| | - Yeo Won Sim
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea
| | - Yong-In Kim
- Center for Bioanalysis, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
| | - Jin Kyun Kim
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Cheol Lee
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jeongran Han
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Chae Un Kim
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - J. Eugene Lee
- Center for Bioanalysis, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
| | - SangYoun Park
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea
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Ahn B, Choi MK, Yum J, Cho IC, Kim JH, Park C. Analysis of allele-specific expression using RNA-seq of the Korean native pig and Landrace reciprocal cross. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2019; 32:1816-1825. [PMID: 31208168 PMCID: PMC6819674 DOI: 10.5713/ajas.19.0097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/25/2019] [Indexed: 11/27/2022]
Abstract
Objective We tried to analyze allele-specific expression in the pig neocortex using bioinformatic analysis of high-throughput sequencing results from the parental genomes and offspring transcriptomes from reciprocal crosses between Korean Native and Landrace pigs. Methods We carried out sequencing of parental genomes and offspring transcriptomes using next generation sequencing. We subsequently carried out genome scale identification of single nucleotide polymorphisms (SNPs) in two different ways using either individual genome mapping or joint genome mapping of the same breed parents that were used for the reciprocal crosses. Using parent-specific SNPs, allele-specifically expressed genes were analyzed. Results Because of the low genome coverage (~4×) of the sequencing results, most SNPs were non-informative for parental lineage determination of the expressed alleles in the offspring and were thus excluded from our analysis. Consequently, 436 SNPs covering 336 genes were applicable to measure the imbalanced expression of paternal alleles in the offspring. By calculating the read ratios of parental alleles in the offspring, we identified seven genes showing allele-biased expression (p<0.05) including three previously reported and four newly identified genes in this study. Conclusion The newly identified allele-specifically expressing genes in the neocortex of pigs should contribute to improving our knowledge on genomic imprinting in pigs. To our knowledge, this is the first study of allelic imbalance using high throughput analysis of both parental genomes and offspring transcriptomes of the reciprocal cross in outbred animals. Our study also showed the effect of the number of informative animals on the genome level investigation of allele-specific expression using RNA-seq analysis in livestock species.
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Affiliation(s)
- Byeongyong Ahn
- Department of Stem Cell and Regenerative Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Min-Kyeung Choi
- Department of Stem Cell and Regenerative Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Joori Yum
- Department of Stem Cell and Regenerative Biotechnology, Konkuk University, Seoul 05029, Korea
| | - In-Cheol Cho
- Subtropical Livestock Research Institute, National Institute of Animal Science, Jeju 63242, Korea
| | - Jin-Hoi Kim
- Department of Stem Cell and Regenerative Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Chankyu Park
- Department of Stem Cell and Regenerative Biotechnology, Konkuk University, Seoul 05029, Korea
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Wei Y, Xiong ZJ, Li J, Zou C, Cairo CW, Klassen JS, Privé GG. Crystal structures of human lysosomal EPDR1 reveal homology with the superfamily of bacterial lipoprotein transporters. Commun Biol 2019; 2:52. [PMID: 30729188 PMCID: PMC6363788 DOI: 10.1038/s42003-018-0262-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 12/11/2018] [Indexed: 01/01/2023] Open
Abstract
EPDR1, a member of the ependymin-related protein family, is a relatively uncharacterized protein found in the lysosomes and secretomes of most vertebrates. Despite having roles in human disease and health, the molecular functions of EPDR1 remain unknown. Here, we present crystal structures of human EPDR1 and reveal that the protein adopts a fold previously seen only in bacterial proteins related to the LolA lipoprotein transporter. EPDR1 forms a homodimer with an overall shape resembling a half-shell with two non-overlapping hydrophobic grooves on the flat side of the hemisphere. EPDR1 can interact with membranes that contain negatively charged lipids, including BMP and GM1, and we suggest that EPDR1 may function as a lysosomal activator protein or a lipid transporter. A phylogenetic analysis reveals that the fold is more widely distributed than previously suspected, with representatives identified in all branches of cellular life.
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Affiliation(s)
- Yong Wei
- Princess Margaret Cancer Centre, Toronto, M5G 1L7 ON Canada
| | - Zi Jian Xiong
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8 ON Canada
| | - Jun Li
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, T6G 2G2 AB Canada
| | - Chunxia Zou
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, T6G 2G2 AB Canada
| | - Christopher W. Cairo
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, T6G 2G2 AB Canada
| | - John S. Klassen
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, T6G 2G2 AB Canada
| | - Gilbert G. Privé
- Princess Margaret Cancer Centre, Toronto, M5G 1L7 ON Canada
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8 ON Canada
- Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7 ON Canada
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Znalesniak EB, Fu T, Salm F, Händel U, Hoffmann W. Transcriptional Responses in the Murine Spleen after Toxoplasma gondii Infection: Inflammasome and Mucus-Associated Genes. Int J Mol Sci 2017; 18:ijms18061245. [PMID: 28604600 PMCID: PMC5486068 DOI: 10.3390/ijms18061245] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 05/24/2017] [Accepted: 06/03/2017] [Indexed: 12/12/2022] Open
Abstract
The spleen plays an important role in coordinating both adaptive and innate immune responses. Here, the transcriptional response to T. gondii infection in the murine spleen was characterized concerning inflammasome sensors (two different models: seven days after oral or four weeks after intraperitoneal infection). Additionally, Tff1KO and Tff3KO mice were investigated because TFF genes are often upregulated during inflammation. The expression of the pattern-recognition receptors Nlrp3, Nlrp12, and Nlrp1a was significantly increased after infection. This increase was diminished in Tff1KO and Tff3KO mice pointing towards a positive regulation of the inflammatory response by Tff1 and Tff3. Furthermore, the transcription of Tff1 (encoding a motogenic lectin) and other secretory genes was analyzed, i.e., gastrokines (Gkn), IgG Fc binding protein (Fcgbp), and the mucin Muc2. The corresponding gene products belong to an interactome protecting mucous epithelia. Tff1 was significantly induced after infection, which might increase the motility of immune cells. In contrast, Gkn3, Fcgbp, and Muc2 were downregulated seven days after oral infection; whereas four weeks after i.p. infection only Gkn3 remained downregulated. This might be an indication that Gkn3, Fcgbp, and Muc2 are involved in the transient disruption of the splenic architecture and its reorganization, which is characteristic after T. gondii infection.
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Affiliation(s)
- Eva B Znalesniak
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
| | - Ting Fu
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
| | - Franz Salm
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
| | - Ulrike Händel
- Institute of Medical Microbiology and Hygiene, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
| | - Werner Hoffmann
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
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Tribl F, Meyer HE, Marcus K. Analysis of organelles within the nervous system: impact on brain and organelle functions. Expert Rev Proteomics 2014; 5:333-51. [DOI: 10.1586/14789450.5.2.333] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Chapel A, Kieffer-Jaquinod S, Sagné C, Verdon Q, Ivaldi C, Mellal M, Thirion J, Jadot M, Bruley C, Garin J, Gasnier B, Journet A. An extended proteome map of the lysosomal membrane reveals novel potential transporters. Mol Cell Proteomics 2013; 12:1572-88. [PMID: 23436907 PMCID: PMC3675815 DOI: 10.1074/mcp.m112.021980] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 02/01/2013] [Indexed: 12/22/2022] Open
Abstract
Lysosomes are membrane-bound endocytic organelles that play a major role in degrading cell macromolecules and recycling their building blocks. A comprehensive knowledge of the lysosome function requires an extensive description of its content, an issue partially addressed by previous proteomic analyses. However, the proteins underlying many lysosomal membrane functions, including numerous membrane transporters, remain unidentified. We performed a comparative, semi-quantitative proteomic analysis of rat liver lysosome-enriched and lysosome-nonenriched membranes and used spectral counts to evaluate the relative abundance of proteins. Among a total of 2,385 identified proteins, 734 proteins were significantly enriched in the lysosomal fraction, including 207 proteins already known or predicted as endo-lysosomal and 94 proteins without any known or predicted subcellular localization. The remaining 433 proteins had been previously assigned to other subcellular compartments but may in fact reside on lysosomes either predominantly or as a secondary location. Many membrane-associated complexes implicated in diverse processes such as degradation, membrane trafficking, lysosome biogenesis, lysosome acidification, signaling, and nutrient sensing were enriched in the lysosomal fraction. They were identified to an unprecedented extent as most, if not all, of their subunits were found and retained by our screen. Numerous transporters were also identified, including 46 novel potentially lysosomal proteins. We expressed 12 candidates in HeLa cells and observed that most of them colocalized with the lysosomal marker LAMP1, thus confirming their lysosomal residency. This list of candidate lysosomal proteins substantially increases our knowledge of the lysosomal membrane and provides a basis for further characterization of lysosomal functions.
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Affiliation(s)
- Agnès Chapel
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Sylvie Kieffer-Jaquinod
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Corinne Sagné
- the ‖Université Paris Descartes, Sorbonne Paris Cité, CNRS, UMR 8192, Centre Universitaire des Saints-Pères, 45 Rue des Saints-Pères, F-75006 Paris, France
| | - Quentin Verdon
- the ‖Université Paris Descartes, Sorbonne Paris Cité, CNRS, UMR 8192, Centre Universitaire des Saints-Pères, 45 Rue des Saints-Pères, F-75006 Paris, France
- §§Graduate School ED 419, Université Paris-Sud 11, Hôpital Bicêtre, F-94276 Le Kremlin Bicêtre France, and
| | - Corinne Ivaldi
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Mourad Mellal
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Jaqueline Thirion
- the **Unité de Recherche en Physiologie Moléculaire, Namur Research Institute for Life Sciences, University of Namur (FUNDP), 61, Rue de Bruxelles B,-5000, Namur, Belgium
| | - Michel Jadot
- the **Unité de Recherche en Physiologie Moléculaire, Namur Research Institute for Life Sciences, University of Namur (FUNDP), 61, Rue de Bruxelles B,-5000, Namur, Belgium
| | - Christophe Bruley
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Jérôme Garin
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Bruno Gasnier
- the ‖Université Paris Descartes, Sorbonne Paris Cité, CNRS, UMR 8192, Centre Universitaire des Saints-Pères, 45 Rue des Saints-Pères, F-75006 Paris, France
| | - Agnès Journet
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
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Dixit SS, Jadot M, Sohar I, Sleat DE, Stock AM, Lobel P. Loss of Niemann-Pick C1 or C2 protein results in similar biochemical changes suggesting that these proteins function in a common lysosomal pathway. PLoS One 2011; 6:e23677. [PMID: 21887293 PMCID: PMC3161064 DOI: 10.1371/journal.pone.0023677] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 07/22/2011] [Indexed: 11/19/2022] Open
Abstract
Niemann-Pick Type C (NPC) disease is a lysosomal storage disorder characterized by accumulation of unesterified cholesterol and other lipids in the endolysosomal system. NPC disease results from a defect in either of two distinct cholesterol-binding proteins: a transmembrane protein, NPC1, and a small soluble protein, NPC2. NPC1 and NPC2 are thought to function closely in the export of lysosomal cholesterol with both proteins binding cholesterol in vitro but they may have unrelated lysosomal roles. To investigate this possibility, we compared biochemical consequences of the loss of either protein. Analyses of lysosome-enriched subcellular fractions from brain and liver revealed similar decreases in buoyant densities of lysosomes from NPC1 or NPC2 deficient mice compared to controls. The subcellular distribution of both proteins was similar and paralleled a lysosomal marker. In liver, absence of either NPC1 or NPC2 resulted in similar alterations in the carbohydrate processing of the lysosomal protease, tripeptidyl peptidase I. These results highlight biochemical alterations in the lysosomal system of the NPC-mutant mice that appear secondary to lipid storage. In addition, the similarity in biochemical phenotypes resulting from either NPC1 or NPC2 deficiency supports models in which the function of these two proteins within lysosomes are linked closely.
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Affiliation(s)
- Sayali S. Dixit
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
- Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey–Robert Wood Johnson Medical School (UMDNJ–RWJMS), Piscataway, New Jersey, United States of America
- Department of Biochemistry, UMDNJ–RWJMS, Piscataway, New Jersey, United States of America
| | - Michel Jadot
- Laboratoire de Chimie Physiologique, Namur Research Institute for Life Sciences and Facultés Universitaires Notre-Dame de la Paix, Namur, Belgium
| | - Istvan Sohar
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
| | - David E. Sleat
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
- Department of Pharmacology, UMDNJ–RWJMS, Piscataway, New Jersey, United States of America
| | - Ann M. Stock
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
- Department of Biochemistry, UMDNJ–RWJMS, Piscataway, New Jersey, United States of America
| | - Peter Lobel
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
- Department of Pharmacology, UMDNJ–RWJMS, Piscataway, New Jersey, United States of America
- * E-mail:
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Della Valle MC, Sleat DE, Zheng H, Moore DF, Jadot M, Lobel P. Classification of subcellular location by comparative proteomic analysis of native and density-shifted lysosomes. Mol Cell Proteomics 2011; 10:M110.006403. [PMID: 21252268 DOI: 10.1074/mcp.m110.006403] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
One approach to the functional characterization of the lysosome lies in the use of proteomic methods to identify proteins in subcellular fractions enriched for this organelle. However, distinguishing between true lysosomal residents and proteins from other cofractionating organelles is challenging. To this end, we implemented a quantitative mass spectrometry approach based on the selective decrease in the buoyant density of liver lysosomes that occurs when animals are treated with Triton-WR1339. Liver lysosome-enriched preparations from control and treated rats were fractionated by isopycnic sucrose density gradient centrifugation. Tryptic peptides derived from gradient fractions were reacted with isobaric tag for relative and absolute quantitation eight-plex labeling reagents and analyzed by two-dimensional liquid chromatography matrix-assisted laser desorption ionization time-of-flight MS. Reporter ion intensities were used to generate relative protein distribution profiles across both types of gradients. A distribution index was calculated for each identified protein and used to determine a probability of lysosomal residence by quadratic discriminant analysis. This analysis suggests that several proteins assigned to the lysosome in other proteomics studies are not true lysosomal residents. Conversely, results support lysosomal residency for other proteins that are either not or only tentatively assigned to this location. The density shift for two proteins, Cu/Zn superoxide dismutase and ATP-binding cassette subfamily B (MDR/TAP) member 6, was corroborated by quantitative Western blotting. Additional balance sheet analyses on differential centrifugation fractions revealed that Cu/Zn superoxide dismutase is predominantly cytosolic with a secondary lysosomal localization whereas ATP-binding cassette subfamily B (MDR/TAP) member 6 is predominantly lysosomal. These results establish a quantitative mass spectrometric/subcellular fractionation approach for identification of lysosomal proteins and underscore the necessity of balance sheet analysis for localization studies.
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Affiliation(s)
- Maria Cecilia Della Valle
- Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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Glial fibrillary acidic protein is elevated in the lysosomal storage disease classical late-infantile neuronal ceroid lipofuscinosis, but is not a component of the storage material. Biochem J 2010; 428:355-62. [PMID: 20370715 DOI: 10.1042/bj20100128] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Classical late-infantile neuronal ceroid lipofuscinosis (LINCL) is a fatal neurodegenerative disease of children caused by mutations in TPP1, the gene encoding the lysosomal protease tripeptidyl peptidase 1. LINCL is characterized by lysosomal accumulation of storage material of which only a single protein component, subunit c of mitochondrial ATP synthase, has been well established to date. Identification of other protein constituents of the storage material could provide useful insights into the pathophysiology of disease and the natural substrates for TPP1. We have therefore initiated a proteomic analysis of storage material in brain from a LINCL mouse model. One protein, GFAP (glial fibrillary acidic protein), was found to be elevated in the LINCL mice compared with normal controls in both isolated storage bodies and a lysosome-enriched subcellular fraction that contains storage material. To determine whether GFAP accumulates within the lysosome in LINCL, we examined its intracellular distribution using subcellular fractionation and morphological methods. These experiments demonstrate that GFAP is not a component of the storage material in LINCL, suggesting that reports of GFAP storage in other NCLs may need to be re-examined. A number of other proteins were elevated in the storage material and/or lysosome-enriched fraction from the LINCL mice, but it remains unclear whether these proteins are true constituents of the storage material or, like GFAP, whether they associate with this material upon purification.
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Iliev DB, Jørgensen SM, Rode M, Krasnov A, Harneshaug I, Jørgensen JB. CpG-induced secretion of MHCIIbeta and exosomes from salmon (Salmo salar) APCs. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2010; 34:29-41. [PMID: 19665478 DOI: 10.1016/j.dci.2009.07.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 07/30/2009] [Accepted: 07/31/2009] [Indexed: 05/28/2023]
Abstract
Major histocompatibility complex class II (MHCII) is encoded by polymorphic genes present in vertebrates and expressed predominately in leukocytes. Upon leukocyte differentiation, intracellular MHCII is dynamically redistributed within the cells and it is expressed at maximal levels on mature antigen presenting cells (APCs). In addition, APCs secrete MHCII within endosome-derived vesicles known as exosomes which possess diverse immunomodulatory properties. Genetic and biochemical data have confirmed that piscine leukocytes express the MHCII components as well as costimulatory molecules that are necessary for the function of APCs. However data concerning the biosynthesis and the distribution of the MHCII complex within leukocytes of lower vertebrates is scarce. The presented data demonstrates for the first time that salmon leukocytes secrete vesicles that contain exosomal markers and the abundance of MHCII indicates that these exosomes are released by APCs. The secretion was specifically induced by CpG stimulation in vitro and it was observed only in head kidney leukocytes but not in splenocyte cultures. Flow cytometry revealed that, unlike splenocytes, the majority of the MHCII-positive head kidney leukocytes were Ig-negative and a population of cells expressing high levels of surface MHCII underwent degranulation upon CpG stimulation suggesting that the MHCII-containing exosomes were derived from maturing salmon APCs. Gene expression analyses have further demonstrated that CpG-B, despite its relatively weak proinflammatory activity compared to LPS, induced expression of a larger group of genes involved in regulation of the adaptive immune response.
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Affiliation(s)
- Dimitar B Iliev
- The Norwegian College of Fishery Science, University of Tromsø, N-9037 Tromsø, Norway
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Abstract
Until recently, a modest number of approx. 40 lysosomal membrane proteins had been identified and even fewer were characterized in their function. In a proteomic study, using lysosomal membranes from human placenta we identified several candidate lysosomal membrane proteins and proved the lysosomal localization of two of them. In the present study, we demonstrate the lysosomal localization of the mouse orthologue of the human C1orf85 protein, which has been termed kidney-predominant protein NCU-G1 (GenBank® accession number: AB027141). NCU-G1 encodes a 404 amino acid protein with a calculated molecular mass of 39 kDa. The bioinformatics analysis of its amino acid sequence suggests it is a type I transmembrane protein containing a single tyrosine-based consensus lysosomal sorting motif at position 400 within the 12-residue C-terminal tail. Its lysosomal localization was confirmed using immunofluorescence with a C-terminally His-tagged NCU-G1 and the lysosomal marker LAMP-1 (lysosome-associated membrane protein-1) as a reference, and by subcellular fractionation of mouse liver after a tyloxapol-induced density shift of the lysosomal fraction using an anti-NCU-G1 antiserum. In transiently transfected HT1080 and HeLa cells, the His-tagged NCU-G1 was detected in two molecular forms with apparent protein sizes of 70 and 80 kDa, and in mouse liver the endogenous wild-type NCU-G1 was detected as a 75 kDa protein. The remarkable difference between the apparent and the calculated molecular masses of NCU-G1 was shown, by digesting the protein with N-glycosidase F, to be due to an extensive glycosylation. The lysosomal localization was impaired by mutational replacement of an alanine residue for the tyrosine residue within the putative sorting motif.
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Sorting of lysosomal proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:605-14. [PMID: 19046998 DOI: 10.1016/j.bbamcr.2008.10.016] [Citation(s) in RCA: 572] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 10/07/2008] [Accepted: 10/30/2008] [Indexed: 11/24/2022]
Abstract
Lysosomes are composed of soluble and transmembrane proteins that are targeted to lysosomes in a signal-dependent manner. The majority of soluble acid hydrolases are modified with mannose 6-phosphate (M6P) residues, allowing their recognition by M6P receptors in the Golgi complex and ensuing transport to the endosomal/lysosomal system. Other soluble enzymes and non-enzymatic proteins are transported to lysosomes in an M6P-independent manner mediated by alternative receptors such as the lysosomal integral membrane protein LIMP-2 or sortilin. Sorting of cargo receptors and lysosomal transmembrane proteins requires sorting signals present in their cytosolic domains. These signals include dileucine-based motifs, DXXLL or [DE]XXXL[LI], and tyrosine-based motifs, YXXØ, which interact with components of clathrin coats such as GGAs or adaptor protein complexes. In addition, phosphorylation and lipid modifications regulate signal recognition and trafficking of lysosomal membrane proteins. The complex interaction of both luminal and cytosolic signals with recognition proteins guarantees the specific and directed transport of proteins to lysosomes.
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Lübke T, Lobel P, Sleat DE. Proteomics of the lysosome. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:625-35. [PMID: 18977398 DOI: 10.1016/j.bbamcr.2008.09.018] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 09/24/2008] [Accepted: 09/30/2008] [Indexed: 01/05/2023]
Abstract
Defects in lysosomal function have been associated with numerous monogenic human diseases typically classified as lysosomal storage diseases. However, there is increasing evidence that lysosomal proteins are also involved in more widespread human diseases including cancer and Alzheimer disease. Thus, there is a continuing interest in understanding the cellular functions of the lysosome and an emerging approach to this is the identification of its constituent proteins by proteomic analyses. To date, the mammalian lysosome has been shown to contain approximately 60 soluble luminal proteins and approximately 25 transmembrane proteins. However, recent proteomic studies based upon affinity purification of soluble components or subcellular fractionation to obtain both soluble and membrane components suggest that there may be many more of both classes of protein resident within this organelle than previously appreciated. Discovery of such proteins has important implications for understanding the function and the dynamics of the lysosome but can also lead the way towards the discovery of the genetic basis for human diseases of hitherto unknown etiology. Here, we describe current approaches to lysosomal proteomics and data interpretation and review the new lysosomal proteins that have recently emerged from such studies.
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Affiliation(s)
- Torben Lübke
- Zentrum Biochemie und Molekulare Zellbiologie, Abteilung Biochemie II, Georg-August Universität Göttingen, 37073 Göttingen, Germany
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16
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Sleat DE, El-Banna M, Sohar I, Kim KH, Dobrenis K, Walkley SU, Lobel P. Residual levels of tripeptidyl-peptidase I activity dramatically ameliorate disease in late-infantile neuronal ceroid lipofuscinosis. Mol Genet Metab 2008; 94:222-33. [PMID: 18343701 PMCID: PMC2467442 DOI: 10.1016/j.ymgme.2008.01.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 01/18/2008] [Accepted: 01/19/2008] [Indexed: 10/22/2022]
Abstract
Classical late-infantile neuronal ceroid lipofuscinosis (LINCL) is a hereditary neurodegenerative disease of childhood that is caused by mutations in the gene (CLN2) encoding the lysosomal protease tripeptidyl-peptidase I (TPPI). LINCL is fatal and there is no treatment of demonstrated efficacy in affected children but preclinical studies with AAV-mediated gene therapy have demonstrated promise in a mouse model. Here, we have generated mouse CLN2-mutants that express different amounts of TPPI activity to benchmark levels required for therapeutic benefits. Approximately 3% of normal TPPI activity in brain delayed disease onset and doubled lifespan to a median of approximately 9 months compared to mice expressing approximately 0.2% of normal levels. Expression of 6% of normal TPPI activity dramatically attenuated disease, with a median lifespan of approximately 20 months which approaches that of unaffected mice. While the lifespan of this hypomorph is shortened, disease is late-onset, less severe and progresses slowly compared to mice expressing lower TPPI levels. For gene therapy and other approaches that restore enzyme activity, these results suggest that 6% of normal TPPI activity throughout the CNS of affected individuals will provide a significant therapeutic benefit but higher levels will be required to cure this disease.
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Affiliation(s)
- David E Sleat
- Center for Advanced Biotechnology and Medicine, Piscataway, NJ 08854, USA.
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17
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Sleat DE, Della Valle MC, Zheng H, Moore DF, Lobel P. The mannose 6-phosphate glycoprotein proteome. J Proteome Res 2008; 7:3010-21. [PMID: 18507433 DOI: 10.1021/pr800135v] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Most luminal lysosomal proteins are synthesized as precursors containing mannose 6-phosphate (Man6-P) and a number of recent studies have conducted affinity purification of Man6-P containing proteins as a step toward defining the composition of the lysosome. Approximately 60 known lysosomal proteins have been found in such studies as well as many other Man-6-P glycoproteins, some of which represent new lysosomal proteins. The latter are of considerable interest from cell-biological and biomedical perspectives, but differentiating between them and other proteins remains a significant challenge. The aim of this study was to conduct a global analysis of the mammalian Man6-P glycoproteome, implementing technical and biostatistical methods to aid in the discovery and validation of lysosomal candidates. We purified Man6-P glycoproteins from 17 individual rat tissues. To distinguish nonspecific contaminants (i.e., abundant or "sticky" proteins that are not fully removed during purification) from specifically purified proteins, we conducted a semiquantitative mass spectrometric comparison of protein levels in nonspecific mock eluates versus specific affinity chromatography eluates to identify those proteins that are specifically purified. We identified 60 known lysosomal proteins, representing nearly all that are currently known to contain Man-6-P. We also find 136 other proteins that are specifically purified but which are not known to have lysosomal function. This approach provides a list of candidate lysosomal proteins and also provides insights into the relative distribution of Man6-P glycoproteins.
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Affiliation(s)
- David E Sleat
- Center for Advanced Biotechnology and Medicine and Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854, USA.
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Gasingirwa MC, Thirion J, Costa C, Flamion B, Lobel P, Jadot M. A method to assess the lysosomal residence of proteins in cultured cells. Anal Biochem 2008; 374:31-40. [PMID: 18082124 DOI: 10.1016/j.ab.2007.11.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Revised: 11/06/2007] [Accepted: 11/16/2007] [Indexed: 10/22/2022]
Abstract
Analytical subcellular fractionation is playing an increasingly important role in proteomic studies to identify and validate components of cellular organelles. For lysosomes, definitive studies in this area have been restricted to rodent tissues due to technical constraints. Our goal was to design a quantitative assay that would allow clear demonstration of lysosomal localization in cultured human cells. We found that culturing HepG2 (human hepatocellular carcinoma) cells in progesterone-containing medium elicited an extensive shift in the buoyant density of lysosomes as measured by isopycnic centrifugation in sucrose density gradients. The density of other organelles remained essentially unchanged; thus, this shift represents a specific test for lysosomal localization. Progesterone treatment of a variety of other cultured cells also elicited a shift in lysosome density. This approach should represent a valuable tool for identification and validation of both luminal and membrane lysosomal proteins.
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Affiliation(s)
- M-C Gasingirwa
- Laboratoire de Chimie Physiologique, Unite de Recherche en Physiologie Moleculaire, Facultes Universitaires Notre-Dame de la Paix, 5000 Namur, Belgium
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19
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Sleat DE, Jadot M, Lobel P. Lysosomal proteomics and disease. Proteomics Clin Appl 2007; 1:1134-46. [PMID: 21136763 DOI: 10.1002/prca.200700250] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Indexed: 11/07/2022]
Abstract
A recent trend in proteomic studies has been to analyze macromolecular complexes such as subcellular organelles instead of complete cells or tissues. This "divide and conquer" approach circumvents some of the formidable problems associated with whole proteome analyses and allows focus on a subset of proteins that may be involved in a particular process or disease of interest. One organelle that has been the focus of considerable attention in proteomic studies is the lysosome, an acidic, membrane-delimited compartment that plays an essential role in the degradation and recycling of biological macromolecules. Lysosomal proteomics have been driven in part by the well-established involvement of this organelle in numerous human diseases, but also by the availability of approaches to selectively visualize and/or isolate subsets of lysosomal proteins. In terms of clinical application, proteomic studies of the lysosome have led to the identification of gene defects in three human hereditary diseases. This review summarizes past progress, current limitations and future directions in the field of lysosomal proteomics.
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Affiliation(s)
- David E Sleat
- Center for Advanced Biotechnology and Medicine, and Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ, USA
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