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Vaz DC, Rodrigues JR, Loureiro-Ferreira N, Müller TD, Sebald W, Redfield C, Brito RMM. Lessons on protein structure from interleukin-4: All disulfides are not created equal. Proteins 2024; 92:219-235. [PMID: 37814578 DOI: 10.1002/prot.26611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 09/09/2023] [Accepted: 09/25/2023] [Indexed: 10/11/2023]
Abstract
Interleukin-4 (IL-4) is a hematopoietic cytokine composed by a four-helix bundle stabilized by an antiparallel beta-sheet and three disulfide bonds: Cys3-Cys127, Cys24-Cys65, and Cys46-Cys99. IL-4 is involved in several immune responses associated to infection, allergy, autoimmunity, and cancer. Besides its physiological relevance, IL-4 is often used as a "model" for protein design and engineering. Hence, to understand the role of each disulfide in the structure and dynamics of IL-4, we carried out several spectroscopic analyses (circular dichroism [CD], fluorescence, nuclear magnetic resonance [NMR]), and molecular dynamics (MD) simulations on wild-type IL-4 and four IL-4 disulfide mutants. All disulfide mutants showed loss of structure, altered interhelical angles, and looser core packings, showing that all disulfides are relevant for maintaining the overall fold and stability of the four-helix bundle motif, even at very low pH. In the absence of the disulfide connecting both protein termini Cys3-Cys127, C3T-IL4 showed a less packed protein core, loss of secondary structure (~9%) and fast motions on the sub-nanosecond time scale (lower S2 order parameters and larger τc correlation time), especially at the two protein termini, loops, beginning of helix A and end of helix D. In the absence of Cys24-Cys65, C24T-IL4 presented shorter alpha-helices (14% loss in helical content), altered interhelical angles, less propensity to form the small anti-parallel beta-sheet and increased dynamics. Simultaneously deprived of two disulfides (Cys3-Cys127 and Cys24-Cys65), IL-4 formed a partially folded "molten globule" with high 8-anilino-1-naphtalenesulphonic acid-binding affinity and considerable loss of secondary structure (~50%decrease), as shown by the far UV-CD, NMR, and MD data.
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Affiliation(s)
- Daniela C Vaz
- School of Health Sciences, Polytechnic of Leiria, Leiria, Portugal
- Chemistry Department, Faculty of Sciences and Technology, University of Coimbra, Coimbra Chemistry Centre, Institute of Molecular Sciences, Coimbra, Portugal
- Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), School of Technology and Management, Polytechnic of Leiria, Leiria, Portugal
- Associate Laboratory in Chemical Engineering (ALiCE), University of Porto, Porto, Portugal
| | - J Rui Rodrigues
- Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), School of Technology and Management, Polytechnic of Leiria, Leiria, Portugal
- Associate Laboratory in Chemical Engineering (ALiCE), University of Porto, Porto, Portugal
| | | | - Thomas D Müller
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
| | - Walter Sebald
- Department of Physiological Chemistry II, Theodor-Boveri-Institute (Biocentre), University of Würzburg, Würzburg, Germany
| | - Christina Redfield
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Rui M M Brito
- Chemistry Department, Faculty of Sciences and Technology, University of Coimbra, Coimbra Chemistry Centre, Institute of Molecular Sciences, Coimbra, Portugal
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2
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Amagai Y, Yamada M, Kowada T, Watanabe T, Du Y, Liu R, Naramoto S, Watanabe S, Kyozuka J, Anelli T, Tempio T, Sitia R, Mizukami S, Inaba K. Zinc homeostasis governed by Golgi-resident ZnT family members regulates ERp44-mediated proteostasis at the ER-Golgi interface. Nat Commun 2023; 14:2683. [PMID: 37160917 PMCID: PMC10170084 DOI: 10.1038/s41467-023-38397-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/01/2023] [Indexed: 05/11/2023] Open
Abstract
Many secretory enzymes acquire essential zinc ions (Zn2+) in the Golgi complex. ERp44, a chaperone operating in the early secretory pathway, also binds Zn2+ to regulate its client binding and release for the control of protein traffic and homeostasis. Notably, three membrane transporter complexes, ZnT4, ZnT5/ZnT6 and ZnT7, import Zn2+ into the Golgi lumen in exchange with protons. To identify their specific roles, we here perform quantitative Zn2+ imaging using super-resolution microscopy and Zn2+-probes targeted in specific Golgi subregions. Systematic ZnT-knockdowns reveal that ZnT4, ZnT5/ZnT6 and ZnT7 regulate labile Zn2+ concentration at the distal, medial, and proximal Golgi, respectively, consistent with their localization. Time-course imaging of cells undergoing synchronized secretory protein traffic and functional assays demonstrates that ZnT-mediated Zn2+ fluxes tune the localization, trafficking, and client-retrieval activity of ERp44. Altogether, this study provides deep mechanistic insights into how ZnTs control Zn2+ homeostasis and ERp44-mediated proteostasis along the early secretory pathway.
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Affiliation(s)
- Yuta Amagai
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Momo Yamada
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, 980-8578, Japan
| | - Toshiyuki Kowada
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi, 980-8577, Japan
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, 980-8578, Japan
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Tomomi Watanabe
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Yuyin Du
- Department of Chemistry, Faculty of Science, Tohoku University, 6-3 Aramaki-aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Rong Liu
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Satoshi Naramoto
- Department of Ecological Developmental Adaptability Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan
- Department of Biological Sciences, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Japan
| | - Satoshi Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi, 980-8577, Japan
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, 980-8578, Japan
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Junko Kyozuka
- Department of Ecological Developmental Adaptability Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Tiziana Anelli
- Division of Genetics and Cell Biology, Vita-Salute University, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
| | - Tiziana Tempio
- Division of Genetics and Cell Biology, Vita-Salute University, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
| | - Roberto Sitia
- Division of Genetics and Cell Biology, Vita-Salute University, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
| | - Shin Mizukami
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi, 980-8577, Japan
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, 980-8578, Japan
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Agency for Medical Research and Development (AMED), Chiyoda, Tokyo, Japan
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi, 980-8577, Japan.
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, 980-8578, Japan.
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan.
- Core Research for Evolutional Science and Technology (CREST), Japan Agency for Medical Research and Development (AMED), Chiyoda, Tokyo, Japan.
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan.
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3
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Xie H, Wang YH, Liu X, Gao J, Yang C, Huang T, Zhang L, Luo X, Gao Z, Wang T, Yan T, Liu Y, Yang P, Yu Q, Liu S, Wang Y, Xiong F, Zhang S, Zhou Q, Wang CY. SUMOylation of ERp44 enhances Ero1α ER retention contributing to the pathogenesis of obesity and insulin resistance. Metabolism 2023; 139:155351. [PMID: 36427672 DOI: 10.1016/j.metabol.2022.155351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/11/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022]
Abstract
OBJECTIVE As the only E2 conjugating enzyme for the SUMO system, Ubc9-mediated SUMOylation has been recognized to regulate diverse biological processes, but its impact on adipocytes relevant to obesity and insulin resistance is yet to be elucidated. METHODS We established adipocyte-specific Ubc9 deficient mice to explore the effects of Ubc9 on obesity and metabolic disorders induced by high-fat diet (HFD) in adult mice. The molecular targets of SUMOylation were explored by liquid chromatography-mass spectrometry, and the regulatory mechanism of SUMOylation in T2D was analyzed. RESULTS Adipocyte-specific depletion of Ubc9 (AdipoQ-Cre-Ubc9fl/fl, Ubc9AKO) protected mice from HFD-induced obesity, insulin resistance, and hepatosteatosis. The Ubc9AKO mice were featured by the reduced HFD-induced endoplasmic reticulum (ER) stress and inflammatory response. Mechanically, over nutrition rendered adipocytes to undergo a SUMOylation turnover characterized by the change of SUMOylation levels and substrates. ERp44 displayed the highest change in terms of SUMOylation levels of substrates involved in ER-related functions. The lack of ERp44 SUMOylation at lysine 76 (K76) located within the thioredoxin (TRX)-like domain by Ubc9 deficiency enhanced its degradation and suppressed its covalent binding to Ero1α, an oxidase that exists in the ER but lacks ER retention motif, thereby alleviating endoplasmic reticulum stress by promoting Ero1α secretion. CONCLUSIONS Our data suggest that modulation of ERp44 SUMOylation in adipocytes could be a feasible strategy against obesity and insulin resistance in clinical settings.
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Affiliation(s)
- Hao Xie
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu-Han Wang
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin Liu
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Department of Interventional Radiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jia Gao
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chunliang Yang
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Teng Huang
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lu Zhang
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xi Luo
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhichao Gao
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ting Wang
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tong Yan
- The Center for Obesity and Metabolic Health, Affiliated Hospital of Southwest Jiaotong University, the Third People's Hospital of Chengdu, 82 Qinglong Road, Chengdu 610031, Sichuan, China
| | - Yanjun Liu
- The Center for Obesity and Metabolic Health, Affiliated Hospital of Southwest Jiaotong University, the Third People's Hospital of Chengdu, 82 Qinglong Road, Chengdu 610031, Sichuan, China
| | - Ping Yang
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qilin Yu
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shiwei Liu
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University. Taiyuan, China
| | - Yi Wang
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Xiong
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shu Zhang
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Qing Zhou
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Cong-Yi Wang
- Department of Respiratory and Critical Care Medicine, the Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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Functional Heterogeneity of Bone Marrow Mesenchymal Stem Cell Subpopulations in Physiology and Pathology. Int J Mol Sci 2022; 23:ijms231911928. [PMID: 36233230 PMCID: PMC9570000 DOI: 10.3390/ijms231911928] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/16/2022] Open
Abstract
Bone marrow mesenchymal stem cells (BMSCs) are multi-potent cell populations and are capable of maintaining bone and body homeostasis. The stemness and potential therapeutic effect of BMSCs have been explored extensively in recent years. However, diverse cell surface antigens and complex gene expression of BMSCs have indicated that BMSCs represent heterogeneous populations, and the natural characteristics of BMSCs make it difficult to identify the specific subpopulations in pathological processes which are often obscured by bulk analysis of the total BMSCs. Meanwhile, the therapeutic effect of total BMSCs is often less effective partly due to their heterogeneity. Therefore, understanding the functional heterogeneity of the BMSC subpopulations under different physiological and pathological conditions could have major ramifications for global health. Here, we summarize the recent progress of functional heterogeneity of BMSC subpopulations in physiology and pathology. Targeting tissue-resident single BMSC subpopulation offers a potentially innovative therapeutic strategy and improves BMSC effectiveness in clinical application.
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5
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Bi Y, Yang Z, Jin M, Zhai K, Wang J, Mao Y, Liu Y, Ding M, Wang H, Wang F, Cai H, Ji G. ERp44 is required for endocardial cushion development by regulating VEGFA secretion in myocardium. Cell Prolif 2022; 55:e13179. [PMID: 35088919 PMCID: PMC8891561 DOI: 10.1111/cpr.13179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/22/2021] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES Endocardial cushions are precursors of the valve septum complex that separates the four heart chambers. Several genes have been implicated in the development of endocardial cushions. Specifically, ERp44 has been found to play a role in the early secretory pathway, but its function in heart development has not been well studied. MATERIALS AND METHODS In this study, we established conditional and tissue-specific knockout mouse models. The morphology, survival rate, the development of heart and endocardial cushion were under evaluation. The relationship between ERp44 and VEGFA was investigated by transcriptome, qPCR, WB, immunofluorescence and immunohistochemistry. RESULTS ERp44 knockout (KO) mice were smaller in size, and most mice died during early postnatal life. KO hearts exhibited the typical phenotypes of congenital heart diseases, such as abnormal heart shapes and severe septal and valvular defects. Similar phenotypes were found in cTNT-Cre+/- ; ERp44fl / fl mice, which indicated that myocardial ERp44 principally controls endocardial cushion formation. Further studies demonstrated that the deletion of ERp44 significantly decreased the proliferation of cushion cells and impaired the endocardial-mesenchymal transition (EndMT), which was followed by endocardial cushion dysplasia. Finally, we found that ERp44 was directly bound to VEGFA and controlled its release, further regulating EndMT. CONCLUSION We demonstrated that ERp44 plays a specific role in heart development. ERp44 contributes to the development of the endocardial cushion by affecting VEGFA-mediated EndMT.
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Affiliation(s)
- Youkun Bi
- Key Laboratory of Interdisciplinary ResearchInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Zhiguang Yang
- Key Laboratory of Interdisciplinary ResearchInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Meng Jin
- Key Laboratory of Interdisciplinary ResearchInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Kui Zhai
- Key Laboratory of Interdisciplinary ResearchInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Jun Wang
- Key Laboratory of Interdisciplinary ResearchInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Yang Mao
- Key Laboratory of Interdisciplinary ResearchInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Yang Liu
- Key Laboratory of Interdisciplinary ResearchInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Mingqin Ding
- National Institute of Biological SciencesBeijingChina
| | - Huiwen Wang
- Key Laboratory of Interdisciplinary ResearchInstitute of BiophysicsChinese Academy of SciencesBeijingChina
| | - Fengchao Wang
- National Institute of Biological SciencesBeijingChina
| | - Hong Cai
- Department of DermatologyAir Force Medical CenterPLABeijingChina
| | - Guangju Ji
- Key Laboratory of Interdisciplinary ResearchInstitute of BiophysicsChinese Academy of SciencesBeijingChina
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6
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Giannone C, Chelazzi MR, Orsi A, Anelli T, Nguyen T, Buchner J, Sitia R. Biogenesis of secretory immunoglobulin M requires intermediate non-native disulfide bonds and engagement of the protein disulfide isomerase ERp44. EMBO J 2022; 41:e108518. [PMID: 34957576 PMCID: PMC8804937 DOI: 10.15252/embj.2021108518] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 11/13/2021] [Accepted: 11/25/2021] [Indexed: 02/03/2023] Open
Abstract
Antibodies of the immunoglobulin M (IgM) class represent the frontline of humoral immune responses. They are secreted as planar polymers in which flanking µ2 L2 "monomeric" subunits are linked by two disulfide bonds, one formed by the penultimate cysteine (C575) in the tailpiece of secretory µ chains (µs tp) and the second by C414 in the Cµ3. The latter bond is not present in membrane IgM. Here, we show that C575 forms a non-native, intra-subunit disulfide bond as a key step in the biogenesis of secretory IgM. The abundance of this unexpected intermediate correlates with the onset and extent of polymerization. The rearrangement of the C-terminal tails into a native quaternary structure is guaranteed by the engagement of protein disulfide isomerase ERp44, which attacks the non-native C575 bonds. The resulting conformational changes promote polymerization and formation of C414 disulfide linkages. This unusual assembly pathway allows secretory polymers to form without the risk of disturbing the role of membrane IgM as part of the B cell antigen receptor.
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Affiliation(s)
- Chiara Giannone
- Division of Genetics and Cell BiologyUniversità Vita‐Salute IRCCS Ospedale San RaffaeleMilanoItaly,Vita‐Salute San Raffaele UniversityMilanItaly
| | - Maria Rita Chelazzi
- Division of Genetics and Cell BiologyUniversità Vita‐Salute IRCCS Ospedale San RaffaeleMilanoItaly,Vita‐Salute San Raffaele UniversityMilanItaly
| | - Andrea Orsi
- Division of Genetics and Cell BiologyUniversità Vita‐Salute IRCCS Ospedale San RaffaeleMilanoItaly,Vita‐Salute San Raffaele UniversityMilanItaly
| | - Tiziana Anelli
- Division of Genetics and Cell BiologyUniversità Vita‐Salute IRCCS Ospedale San RaffaeleMilanoItaly,Vita‐Salute San Raffaele UniversityMilanItaly
| | - Tuan Nguyen
- Department ChemistryTechnical University MunichGarchingGermany
| | | | - Roberto Sitia
- Division of Genetics and Cell BiologyUniversità Vita‐Salute IRCCS Ospedale San RaffaeleMilanoItaly,Vita‐Salute San Raffaele UniversityMilanItaly
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7
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Linders PTA, Ioannidis M, ter Beest M, van den Bogaart G. Fluorescence Lifetime Imaging of pH along the Secretory Pathway. ACS Chem Biol 2022; 17:240-251. [PMID: 35000377 PMCID: PMC8787756 DOI: 10.1021/acschembio.1c00907] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Many cellular processes
are dependent on correct pH levels, and
this is especially important for the secretory pathway. Defects in
pH homeostasis in distinct organelles cause a wide range of diseases,
including disorders of glycosylation and lysosomal storage diseases.
Ratiometric imaging of the pH-sensitive mutant of green fluorescent
protein, pHLuorin, has allowed for targeted pH measurements in various
organelles, but the required sequential image acquisition is intrinsically
slow and therefore the temporal resolution is unsuitable to follow
the rapid transit of cargo between organelles. Therefore, we applied
fluorescence lifetime imaging microscopy (FLIM) to measure intraorganellar
pH with just a single excitation wavelength. We first validated this
method by confirming the pH in multiple compartments along the secretory
pathway and compared the pH values obtained by the FLIM-based measurements
with those obtained by conventional ratiometric imaging. Then, we
analyzed the dynamic pH changes within cells treated with Bafilomycin
A1, to block the vesicular ATPase, and Brefeldin A, to block endoplasmic
reticulum (ER)–Golgi trafficking. Finally, we followed the
pH changes of newly synthesized molecules of the inflammatory cytokine
tumor necrosis factor-α while they were in transit from the
ER via the Golgi to the plasma membrane. The toolbox we present here
can be applied to measure intracellular pH with high spatial and temporal
resolution and can be used to assess organellar pH in disease models.
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Affiliation(s)
- Peter T. A. Linders
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Melina Ioannidis
- Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, Netherlands
| | - Martin ter Beest
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Geert van den Bogaart
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, Netherlands
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8
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Zhu D, Gao J, Tang C, Xu Z, Sun T. Single-Cell RNA Sequencing of Bone Marrow Mesenchymal Stem Cells from the Elderly People. Int J Stem Cells 2021; 15:173-182. [PMID: 34711696 PMCID: PMC9148839 DOI: 10.15283/ijsc21042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 07/26/2021] [Accepted: 08/24/2021] [Indexed: 11/09/2022] Open
Abstract
Background and Objectives Bone marrow mesenchymal stem cells (BMSCs) show considerable promise in regenerative medicine. Many studies demonstrated that BMSCs cultured in vitro were highly heterogeneous and composed of diverse cell subpopulations, which may be the basis of their multiple biological characteristics. However, the exact cell subpopulations that make up BMSCs are still unknown. Methods and Results In this study, we used single-cell RNA sequencing (scRNA-Seq) to divide 6,514 BMSCs into three clusters. The number and corresponding proportion of cells in clusters 1 to 3 were 3,766 (57.81%), 1,720 (26.40%), and 1,028 (15.78%). The gene expression profile and function of the cells in the same cluster were similar. The vast majority of cells expressed the markers defining BMSCs by flow cytometry and gene expression analysis. Each cluster had at least 20 differentially expressed genes (DEGs). We conducted Gene Ontology enrichment analysis on the top 20 DEGs of each cluster and found that the three clusters had different functions, which were related to self-renewal, multilineage differentiation and cytokine secretion, respectively. In addition, the function of the top 20 DEGs of each cluster was checked by the National Center for Biotechnology Information gene database to further verify our hypothesis. Conclusions This study indicated that scRNA-Seq can be used to divide BMSCs into different subpopulations, demonstrating the heterogeneity of BMSCs.
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Affiliation(s)
- Dezhou Zhu
- Department of Orthopaedics, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Jie Gao
- Department of Orthopaedics, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Chengxuan Tang
- Department of Orthopaedics, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Zheng Xu
- Department of Outpatient, The First Retired Cadre Sanitarium of Beijing Garrison in Fengtai District, Beijing, China.,School of Clinical Medicine, The Second Military Medical University, Shanghai, China
| | - Tiansheng Sun
- Department of Orthopaedics, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, China
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9
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A virtuous cycle operated by ERp44 and ERGIC-53 guarantees proteostasis in the early secretory compartment. iScience 2021; 24:102244. [PMID: 33763635 PMCID: PMC7973864 DOI: 10.1016/j.isci.2021.102244] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/01/2021] [Accepted: 02/25/2021] [Indexed: 01/13/2023] Open
Abstract
The composition of the secretome depends on the combined action of cargo receptors that facilitate protein transport and sequential checkpoints that restrict it to native conformers. Acting after endoplasmic reticulum (ER)-resident chaperones, ERp44 retrieves its clients from downstream compartments. To guarantee efficient quality control, ERp44 should exit the ER as rapidly as its clients, or more. Here, we show that appending ERp44 to different cargo proteins increases their secretion rates. ERp44 binds the cargo receptor ER-Golgi intermediate compartment (ERGIC)-53 in the ER to negotiate preferential loading into COPII vesicles. Silencing ERGIC-53, or competing for its COPII binding with 4-phenylbutyrate, causes secretion of Prdx4, an enzyme that relies on ERp44 for intracellular localization. In more acidic, zinc-rich downstream compartments, ERGIC-53 releases its clients and ERp44, which can bind and retrieve non-native conformers via KDEL receptors. By coupling the transport of cargoes and inspector proteins, cells ensure efficiency and fidelity of secretion.
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10
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Tempio T, Anelli T. The pivotal role of ERp44 in patrolling protein secretion. J Cell Sci 2020; 133:133/21/jcs240366. [PMID: 33173013 DOI: 10.1242/jcs.240366] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Interactions between protein ligands and receptors are the main language of intercellular communication; hence, how cells select proteins to be secreted or presented on the plasma membrane is a central concern in cell biology. A series of checkpoints are located along the secretory pathway, which ensure the fidelity of such protein signals (quality control). Proteins that pass the checkpoints operated in the endoplasmic reticulum (ER) by the binding immunoglobulin protein (BiP; also known as HSPA5 and GRP78) and the calnexin-calreticulin systems, must still overcome additional scrutiny in the ER-Golgi intermediate compartment (ERGIC) and the Golgi. One of the main players of this process in all metazoans is the ER-resident protein 44 (ERp44); by cycling between the ER and the Golgi, ERp44 controls the localization of key enzymes designed to act in the ER but that are devoid of suitable localization motifs. ERp44 also patrols the secretion of correctly assembled disulfide-linked oligomeric proteins. Here, we discuss the mechanisms driving ERp44 substrate recognition, with important consequences on the definition of 'thiol-mediated quality control'. We also describe how pH and zinc gradients regulate the functional cycle of ERp44, coupling quality control and membrane trafficking along the early secretory compartment.
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Affiliation(s)
- Tiziana Tempio
- Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan 20132, Italy.,IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
| | - Tiziana Anelli
- Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan 20132, Italy .,IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
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11
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Sicari D, Chatziioannou A, Koutsandreas T, Sitia R, Chevet E. Role of the early secretory pathway in SARS-CoV-2 infection. J Cell Biol 2020; 219:151984. [PMID: 32725137 PMCID: PMC7480111 DOI: 10.1083/jcb.202006005] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022] Open
Abstract
Similar to other RNA viruses, SARS-CoV-2 must (1) enter a target/host cell, (2) reprogram it to ensure its replication, (3) exit the host cell, and (4) repeat this cycle for exponential growth. During the exit step, the virus hijacks the sophisticated machineries that host cells employ to correctly fold, assemble, and transport proteins along the exocytic pathway. Therefore, secretory pathway-mediated assemblage and excretion of infective particles represent appealing targets to reduce the efficacy of virus biogenesis, if not to block it completely. Here, we analyze and discuss the contribution of the molecular machines operating in the early secretory pathway in the biogenesis of SARS-CoV-2 and their relevance for potential antiviral targeting. The fact that these molecular machines are conserved throughout evolution, together with the redundancy and tissue specificity of their components, provides opportunities in the search for unique proteins essential for SARS-CoV-2 biology that could also be targeted with therapeutic objectives. Finally, we provide an overview of recent evidence implicating proteins of the early secretory pathway as potential antiviral targets with effective therapeutic applications.
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Affiliation(s)
- Daria Sicari
- Inserm U1242, Université de Rennes, Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Aristotelis Chatziioannou
- e-NIOS Applications PC, Kallithea-Athens, Greece.,Center of Systems Biology, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Theodoros Koutsandreas
- e-NIOS Applications PC, Kallithea-Athens, Greece.,Center of Systems Biology, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | | | - Eric Chevet
- Inserm U1242, Université de Rennes, Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France.,Università Vita-Salute San Raffaele, Milan, Italy
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12
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Klyukin K, Alexandrov V. Kinetics of pH-dependent interactions between PD-1 and PD-L1 immune checkpoint proteins from molecular dynamics. Proteins 2020; 88:1162-1168. [PMID: 32105362 DOI: 10.1002/prot.25885] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/05/2020] [Accepted: 02/23/2020] [Indexed: 12/17/2022]
Abstract
Immune checkpoint blockade of signaling pathways such as PD-1/PD-L1 has recently opened up a new avenue for highly efficient immunotherapeutic strategies to treat cancer. Since tumor microenvironments are characterized by lower pH (5.5-7.0), pH-dependent protein-ligand interactions can be exploited as efficient means to regulate drug affinity and specificity for a variety of malignancies. In this article, we investigate the mechanism and kinetics of pH-dependent binding and unbinding processes for the PD-1/PD-L1 checkpoint pair employing classical molecular dynamics simulations. Two representative pH levels corresponding to circumneutral physiological conditions of blood (pH 7.4) and acidic tumor microenvironment (pH 5.5) are considered. Our calculations demonstrate that pH plays a key role in protein-ligand interactions with small pH changes leading to several orders of magnitude increase in binding affinity. By identifying the binding pocket in the PD-1/PD-L1 complex, we show a pivotal role of the His68 protonation state of PD-1in the complex stabilization at low pH. The results on the reaction rate constants are in qualitative agreement with available experimental data. The obtained molecular details are important for further engineering of binding/unbinding kinetics to formulate more efficient immune checkpoint blockade strategies.
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Affiliation(s)
- Konstantin Klyukin
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Vitaly Alexandrov
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska.,Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska
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13
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Keiser KJ, Barlowe C. Molecular dissection of the Erv41-Erv46 retrograde receptor reveals a conserved cysteine-rich region in Erv46 required for retrieval activity. Mol Biol Cell 2019; 31:209-220. [PMID: 31825724 PMCID: PMC7001479 DOI: 10.1091/mbc.e19-08-0484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Erv41-Erv46 complex is a conserved retrograde cargo receptor that retrieves ER resident proteins from Golgi compartments in a pH-dependent manner. Here we functionally dissect the Erv46 subunit and define an approximately 60 residue cysteine-rich region that is unique to the Erv46 family of proteins. This cysteine-rich region contains two vicinal cysteine pairs in CXXC and CCXXC configurations that are each required for retrieval activity in cells. Mutation of the individual cysteine residues produced stable Erv46 proteins that were partially reduced and form mixed-disulfide species on nonreducing gels. Conserved hydrophobic amino acids within the cysteine-rich region of Erv46 were also required for retrieval function in cells. In vitro binding experiments showed that this hydrophobic patch is required for direct cargo binding. Surprisingly, the Erv46 cysteine mutants continued to bind cargo in cell-free assays and produced an increased level of Erv46-cargo complexes in cell extracts suggesting that disulfide linkages in the cysteine-rich region perform a role in releasing bound cargo. On the basis of these findings, we propose that both pH and redox environments regulate cargo binding to a hydrophobic site within the cysteine-rich region of Erv46.
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Affiliation(s)
- Kristofer J Keiser
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Charles Barlowe
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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14
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Su Y, Wang B, Zhang Y, Ruan Z, Bai H, Wan J, Xu C, Li G, Wang S, Ai H, Xiong L, Geng H. Mass spectrometric determination of disulfide bonds and free cysteine in grass carp IgM isoforms. FISH & SHELLFISH IMMUNOLOGY 2019; 95:287-296. [PMID: 31669895 DOI: 10.1016/j.fsi.2019.10.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 09/21/2019] [Accepted: 10/24/2019] [Indexed: 06/10/2023]
Abstract
Disulfide bonds are fundamental in establishing Ig structure and maintaining Ig biological function. Here, we analysed disulfide bonds and free cysteine in three grass carp IgM isoforms (monomeric, dimeric/trimeric, and tetrameric IgM) by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The results revealed that Cys574 residue status at the C-terminal tail differed substantially in monomeric IgM in comparison with polymeric IgM, Cys574 was found as free thiol in monomeric IgM, while it formed disulfide linkages in dimeric/trimeric and tetrameric IgM. Five intra-chain disulfide bonds in the CH1~CH4 and CL1 domains, as well as one H-H and one H-L inter-chain disulfide linkages, were also observed and shown identical connectivity in monomeric, dimeric/trimeric, and tetrameric IgM. These findings represent the first experimental assignments of disulfide linkages of grass carp IgM and reveal that grass carp IgM isoform formation is due to alternative disulfide bonds connecting the Cys574 residue at the C-terminal tail.
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Affiliation(s)
- Yiling Su
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Bing Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Ying Zhang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Zilun Ruan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Hao Bai
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Jian Wan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Chen Xu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Guoqi Li
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Shengqiang Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Hui Ai
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Li Xiong
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Hui Geng
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
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15
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Oguro A, Imaoka S. Thioredoxin-related transmembrane protein 2 (TMX2) regulates the Ran protein gradient and importin-β-dependent nuclear cargo transport. Sci Rep 2019; 9:15296. [PMID: 31653923 PMCID: PMC6814788 DOI: 10.1038/s41598-019-51773-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/27/2019] [Indexed: 01/05/2023] Open
Abstract
TMX2 is a thioredoxin family protein, but its functions have not been clarified. To elucidate the function of TMX2, we explored TMX2-interacting proteins by LC-MS. As a result, importin-β, Ran GTPase (Ran), RanGAP, and RanBP2 were identified. Importin-β is an adaptor protein which imports cargoes from cytosol to the nucleus, and is exported into the cytosol by interaction with RanGTP. At the cytoplasmic nuclear pore, RanGAP and RanBP2 facilitate hydrolysis of RanGTP to RanGDP and the disassembly of the Ran-importin-β complex, which allows the recycling of importin-β and reentry of Ran into the nucleus. Despite its interaction of TMX2 with importin-β, we showed that TMX2 is not a transport cargo. We found that TMX2 localizes in the outer nuclear membrane with its N-terminus and C-terminus facing the cytoplasm, where it co-localizes with importin-β and Ran. Ran is predominantly distributed in the nucleus, but TMX2 knockdown disrupted the nucleocytoplasmic Ran gradient, and the cysteine 112 residue of Ran was important in its regulation by TMX2. In addition, knockdown of TMX2 suppressed importin-β-mediated transport of protein. These results suggest that TMX2 works as a regulator of protein nuclear transport, and that TMX2 facilitates the nucleocytoplasmic Ran cycle by interaction with nuclear pore proteins.
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Affiliation(s)
- Ami Oguro
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Japan. .,Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan.
| | - Susumu Imaoka
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Japan.
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16
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The role of ERp44 in glucose and lipid metabolism. Arch Biochem Biophys 2019; 671:175-184. [PMID: 31283909 DOI: 10.1016/j.abb.2019.06.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 06/25/2019] [Accepted: 06/27/2019] [Indexed: 12/21/2022]
Abstract
Endoplasmic Reticulum Protein 44 (ERp44) is a member of the PDI family, named for a molecular weight of 44 kD. White adipose tissue has metabolic and endocrine functions that are important to metabolism. The role of ERp44 in glucose and lipid metabolism is not known yet. The current study was undertaken to investigate the implication of ERp44 in glucose and lipid metabolism. In this study, we generated and characterized ERp44-/- mice. We used type 2 diabetes models and ERp44 knockout mice to show the implication of ERp44 in glucose and lipid metabolism. Knockout newborns had lower blood glucose compared to wild-type. Adult knockouts had abnormal intraperitoneal, glucose, insulin and pyruvic acid tolerance. Lipocytes were smaller and fewer in knockout mice compared to wild-type. Knockouts resisted to high-fat diet-induced obesity. ERp44 expression in white adipose tissue decreased significantly in type 2 diabetes models. Results suggest that ERp44 is closely associated with glucose and lipid metabolism.
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17
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Yang Y, Davis I, Matsui T, Rubalcava I, Liu A. Quaternary structure of α-amino-β-carboxymuconate-ϵ-semialdehyde decarboxylase (ACMSD) controls its activity. J Biol Chem 2019; 294:11609-11621. [PMID: 31189654 PMCID: PMC6663868 DOI: 10.1074/jbc.ra119.009035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/10/2019] [Indexed: 01/07/2023] Open
Abstract
α-Amino-β-carboxymuconate-ϵ-semialdehyde decarboxylase (ACMSD) plays an important role in l-tryptophan degradation via the kynurenine pathway. ACMSD forms a homodimer and is functionally inactive as a monomer because its catalytic assembly requires an arginine residue from a neighboring subunit. However, how the oligomeric state and self-association of ACMSD are controlled in solution remains unexplored. Here, we demonstrate that ACMSD from Pseudomonas fluorescens can self-assemble into homodimer, tetramer, and higher-order structures. Using size-exclusion chromatography coupled with small-angle X-ray scattering (SEC-SAXS) analysis, we investigated the ACMSD tetramer structure, and fitting the SAXS data with X-ray crystal structures of the monomeric component, we could generate a pseudo-atomic structure of the tetramer. This analysis revealed a tetramer model of ACMSD as a head-on dimer of dimers. We observed that the tetramer is catalytically more active than the dimer and is in equilibrium with the monomer and dimer. Substituting a critical residue of the dimer-dimer interface, His-110, altered the tetramer dissociation profile by increasing the higher-order oligomer portion in solution without changing the X-ray crystal structure. ACMSD self-association was affected by pH, ionic strength, and other electrostatic interactions. Alignment of ACMSD sequences revealed that His-110 is highly conserved in a few bacteria that utilize nitrobenzoic acid as a sole source of carbon and energy, suggesting a dedicated functional role of ACMSD's self-assembly into the tetrameric and higher-order structures. These results indicate that the dynamic oligomerization status potentially regulates ACMSD activity and that SEC-SAXS coupled with X-ray crystallography is a powerful tool for studying protein self-association.
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Affiliation(s)
- Yu Yang
- Department of Chemistry, University of Texas, San Antonio, Texas 78249
| | - Ian Davis
- Department of Chemistry, University of Texas, San Antonio, Texas 78249
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025
| | - Ivan Rubalcava
- Department of Chemistry, University of Texas, San Antonio, Texas 78249
| | - Aimin Liu
- Department of Chemistry, University of Texas, San Antonio, Texas 78249, To whom correspondence should be addressed. Tel.:
210-458-7062; E-mail:
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18
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Abstract
The site of protein folding and maturation for the majority of proteins that are secreted, localized to the plasma membrane or targeted to endomembrane compartments is the endoplasmic reticulum (ER). It is essential that proteins targeted to the ER are properly folded in order to carry out their function, as well as maintain protein homeostasis, as accumulation of misfolded proteins could lead to the formation of cytotoxic aggregates. Because protein folding is an error-prone process, the ER contains protein quality control networks that act to optimize proper folding and trafficking of client proteins. If a protein is unable to reach its native state, it is targeted for ER retention and subsequent degradation. The protein quality control networks of the ER that oversee this evaluation or interrogation process that decides the fate of maturing nascent chains is comprised of three general types of families: the classical chaperones, the carbohydrate-dependent system, and the thiol-dependent system. The cooperative action of these families promotes protein quality control and protein homeostasis in the ER. This review will describe the families of the ER protein quality control network and discuss the functions of individual members.
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Affiliation(s)
- Benjamin M Adams
- Department of Biochemistry and Molecular Biology, University of Massachusetts, 240 Thatcher Road, Amherst, MA, 01003, USA
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Michela E Oster
- Department of Biochemistry and Molecular Biology, University of Massachusetts, 240 Thatcher Road, Amherst, MA, 01003, USA
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, University of Massachusetts, 240 Thatcher Road, Amherst, MA, 01003, USA.
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA.
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19
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Liyanage D, Omeka W, Lee J. Molecular characterization, host defense mechanisms, and functional analysis of ERp44 from big-belly seahorse: A novel member of the teleost thioredoxin family present in the endoplasmic reticulum. Comp Biochem Physiol B Biochem Mol Biol 2019; 232:31-41. [DOI: 10.1016/j.cbpb.2019.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/25/2019] [Accepted: 02/01/2019] [Indexed: 12/22/2022]
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20
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Matsusaki M, Kanemura S, Kinoshita M, Lee YH, Inaba K, Okumura M. The Protein Disulfide Isomerase Family: from proteostasis to pathogenesis. Biochim Biophys Acta Gen Subj 2019; 1864:129338. [PMID: 30986509 DOI: 10.1016/j.bbagen.2019.04.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 03/08/2019] [Accepted: 04/02/2019] [Indexed: 12/13/2022]
Abstract
In mammalian cells, nearly one-third of proteins are inserted into the endoplasmic reticulum (ER), where they undergo oxidative folding and chaperoning assisted by approximately 20 members of the protein disulfide isomerase family (PDIs). PDIs consist of multiple thioredoxin-like domains and recognize a wide variety of proteins via highly conserved interdomain flexibility. Although PDIs have been studied intensely for almost 50 years, exactly how they maintain protein homeostasis in the ER remains unknown, and is important not only for fundamental biological understanding but also for protein misfolding- and aggregation-related pathophysiology. Herein, we review recent advances in structural biology and biophysical approaches that explore the underlying mechanism by which PDIs fulfil their distinct functions to promote productive protein folding and scavenge misfolded proteins in the ER, the primary factory for efficient production of the secretome.
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Affiliation(s)
- Motonori Matsusaki
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aramaki aza Aoba 6-3, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Shingo Kanemura
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aramaki aza Aoba 6-3, Aoba-ku, Sendai, Miyagi 980-8578, Japan; School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo 669-1337, Japan
| | - Misaki Kinoshita
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aramaki aza Aoba 6-3, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Young-Ho Lee
- Protein Structure Group, Korea Basic Science Institute, Ochang, Chungbuk 28199, South Korea; Bio-Analytical Science, University of Science and Technology, Daejeon 34113, South Korea
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
| | - Masaki Okumura
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aramaki aza Aoba 6-3, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
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21
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Fu YL, Zhang B, Mu TW. LMAN1 (ERGIC-53) promotes trafficking of neuroreceptors. Biochem Biophys Res Commun 2019; 511:356-362. [PMID: 30791981 DOI: 10.1016/j.bbrc.2019.02.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 02/10/2019] [Indexed: 12/15/2022]
Abstract
The endoplasmic reticulum-Golgi intermediate compartment protein-53 (ERGIC-53, aka LMAN1), which cycles between the endoplasmic reticulum (ER) and Golgi, is a known cargo receptor for a number of soluble proteins. However, whether LMAN1 plays a role as a trafficking factor in the central nervous system is largely unknown. Here, we determined the role of LMAN1 on endogenous protein levels of the Cys-loop superfamily of neuroreceptors, including gamma-aminobutyric acid type A receptors (GABAARs), 5-hydroxytryptamine (serotonin) type 3 (5-HT3) receptors, and nicotinic acetylcholine receptors (nAChRs). Knockdown of LMAN1 reduces the surface trafficking of endogenous β3 subunits of GABAARs in mouse hypothalamic GT1-7 neurons. Furthermore, Western blot analysis of brain homogenates from LMAN1 knockout mice demonstrated that loss of LMAN1 decreases the total protein levels of 5HT3A receptors and γ2 subunits of GABAARs. LMAN1 knockout regulates the ER proteostasis network by upregulating ERP44 without changing calnexin levels. Interestingly, despite the critical role of the glycan-binding function of LMAN1 in its other known cargo clients, LMAN1 interacts with GABAARs in a glycan-independent manner. In summary, LMAN1 is a trafficking factor for certain neuroreceptors in the central nervous system. This is the first report of LMAN1 function in membrane protein trafficking.
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Affiliation(s)
- Yan-Lin Fu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Bin Zhang
- Genomic Medicine Institute, Lerner Research Institute of Cleveland Clinic, Cleveland, OH, USA
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
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22
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Zinc regulates ERp44-dependent protein quality control in the early secretory pathway. Nat Commun 2019; 10:603. [PMID: 30723194 PMCID: PMC6363758 DOI: 10.1038/s41467-019-08429-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 01/09/2019] [Indexed: 01/14/2023] Open
Abstract
Zinc ions (Zn2+) are imported into the early secretory pathway by Golgi-resident transporters, but their handling and functions are not fully understood. Here, we show that Zn2+ binds with high affinity to the pH-sensitive chaperone ERp44, modulating its localization and ability to retrieve clients like Ero1α and ERAP1 to the endoplasmic reticulum (ER). Silencing the Zn2+ transporters that uptake Zn2+ into the Golgi led to ERp44 dysfunction and increased secretion of Ero1α and ERAP1. High-resolution crystal structures of Zn2+-bound ERp44 reveal that Zn2+ binds to a conserved histidine-cluster. The consequent large displacements of the regulatory C-terminal tail expose the substrate-binding surface and RDEL motif, ensuring client capture and retrieval. ERp44 also forms Zn2+-bridged homodimers, which dissociate upon client binding. Histidine mutations in the Zn2+-binding sites compromise ERp44 activity and localization. Our findings reveal a role of Zn2+ as a key regulator of protein quality control at the ER-Golgi interface. Zinc ions (Zn2+) are imported by Golgi-resident transporters but the function of zinc in the early secretory pathway has remained unknown. Here the authors find that Zn2+ regulates protein quality control in the early secretory pathway by demonstrating that the pH-sensitive chaperone ERp44 binds Zn2+ and solving the Zn2+-bound ERp44 structure.
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23
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Reifenrath M, Boles E. A superfolder variant of pH-sensitive pHluorin for in vivo pH measurements in the endoplasmic reticulum. Sci Rep 2018; 8:11985. [PMID: 30097598 PMCID: PMC6086885 DOI: 10.1038/s41598-018-30367-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 07/27/2018] [Indexed: 11/09/2022] Open
Abstract
Many cellular processes are regulated via pH, and maintaining the pH of different organelles is crucial for cell survival. A pH-sensitive GFP variant, the so-called pHluorin, has proven to be a valuable tool to study the pH of the cytosol, mitochondria and other organelles in vivo. We found that the fluorescence intensity of Endoplasmic Reticulum (ER)-targeted pHluorin in the yeast Saccharomyces cerevisiae was very low and barely showed pH sensitivity, probably due to misfolding in the oxidative environment of the ER. We therefore developed a superfolder variant of pHluorin which enabled us to monitor pH changes in the ER and the cytosol of S. cerevisiae in vivo. The superfolder pHluorin variant is likely to be functional in cells of different organisms as well as in additional compartments that originate from the secretory pathway like the Golgi apparatus and pre-vacuolar compartments, and therefore has a broad range of possible future applications.
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Affiliation(s)
- Mara Reifenrath
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438, Frankfurt am Main, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438, Frankfurt am Main, Germany.
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24
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Narayan A, Naganathan AN. Switching Protein Conformational Substates by Protonation and Mutation. J Phys Chem B 2018; 122:11039-11047. [PMID: 30048131 DOI: 10.1021/acs.jpcb.8b05108] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein modules that regulate the availability and conformational status of transcription factors determine the rapidity, duration, and magnitude of cellular response to changing conditions. One such system is the single-gene product Cnu, a four-helix bundle transcription co-repressor, which acts as a molecular thermosensor regulating the expression of virulence genes in enterobacteriaceae through modulation of its native conformational ensemble. Cnu and related genes have also been implicated in pH-dependent expression of virulence genes. We hypothesize that protonation of a conserved buried histidine (H45) in Cnu promotes large electrostatic frustration, thus disturbing the H-NS, a transcription factor, binding face. Spectroscopic and calorimetric methods reveal that H45 exhibits a suppressed p Ka of ∼5.1, the protonation of which switches the conformation to an alternate native ensemble in which the fourth helix is disordered. The population redistribution can also be achieved through a mutation H45V, which does not display any switching behavior at pH values greater than 4. The Wako-Saitô-Muñoz-Eaton (WSME) statistical mechanical model predicts specific differences in the conformations and fluctuations of the fourth and first helices of Cnu determining the observed pH response. We validate these predictions through fluorescence lifetime measurements of a sole tryptophan, highlighting the presence of both native and non-native interactions in the regions adjoining the binding face of Cnu. Our combined experimental-computational study thus shows that Cnu acts both as a thermo- and pH-sensor orchestrated via a subtle but quantifiable balance between the weak packing of a structural element and protonation of a buried histidine that promotes electrostatic frustration.
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Affiliation(s)
- Abhishek Narayan
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences , Indian Institute of Technology Madras , Chennai 600036 , India
| | - Athi N Naganathan
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences , Indian Institute of Technology Madras , Chennai 600036 , India
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25
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Li H, Yang K, Wang W, Niu Y, Li J, Dong Y, Liu Y, Wang CC, Wang L, Liang H. Crystal and solution structures of human protein-disulfide isomerase-like protein of the testis (PDILT) provide insight into its chaperone activity. J Biol Chem 2018; 293:1192-1202. [PMID: 29203529 PMCID: PMC5787798 DOI: 10.1074/jbc.m117.797290] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 12/01/2017] [Indexed: 01/07/2023] Open
Abstract
Protein-disulfide isomerase-like protein of the testis (PDILT), a member of the protein-disulfide isomerase family, is a chaperone essential for the folding of spermatogenesis-specific proteins in male postmeiotic germ cells. However, the structural mechanisms that regulate the chaperone function of PDILTs are unknown. Here, we report the structures of human PDILT (hPDILT) determined by X-ray crystallography to 2.4 Å resolution and small-angle X-ray scattering (SAXS). Distinct from previously reported U-like structures of related PDI family proteins, our structures revealed that hPDILT folds into a compact L-like structure in crystals and into an extended chain-like structure in solution. The hydrophobic regions and the hydrophobic pockets in hPDILT, which are important for substrate recognition, were clearly delineated in the crystal structure. Moreover, our results of the SAXS analysis and of structure-based substitutions and truncations indicated that the C-terminal tail in hPDILT is required for suppression of aggregation of denatured proteins, suggesting that the tail is crucial for the chaperone activity of PDILT. Taken together, our findings have identified the critical regions and conformational changes of PDILT that enable and control its activity. These results advance our understanding of the structural mechanisms involved in the chaperone activity of PDILT.
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Affiliation(s)
- Huanhuan Li
- From the National Laboratory of Biomacromolecules, ,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, and
| | - Kai Yang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, ,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, and
| | - Wenjia Wang
- the Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences and
| | - Yingbo Niu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, ,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, and
| | - Jun Li
- From the National Laboratory of Biomacromolecules, ,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, and
| | - Yuhui Dong
- the Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences and
| | - Yingfang Liu
- From the National Laboratory of Biomacromolecules, ,the School of Medicine and
| | - Chih-chen Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, ,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, and
| | - Lei Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, ,the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, and , To whom correspondence may be addressed. E-mail:
| | - Huanhuan Liang
- From the National Laboratory of Biomacromolecules, ,School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Guangzhou 510275, China, To whom correspondence may be addressed. E-mail:
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26
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Hampe L, Xu C, Harris PWR, Chen J, Liu M, Middleditch M, Radjainia M, Wang Y, Mitra AK. Synthetic peptides designed to modulate adiponectin assembly improve obesity-related metabolic disorders. Br J Pharmacol 2017; 174:4478-4492. [PMID: 28945274 DOI: 10.1111/bph.14050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 07/21/2017] [Accepted: 09/07/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Adiponectin, an adipokine possessing profound insulin-sensitizing and anti-inflammatory properties, is a potent biotherapeutic agent . The trimeric adiponectin subunit assembles into hexameric and functionally important higher molecular weight (HMW) forms, controlled by the endoplasmic reticulum protein 44 (ERp44). Obesity-induced ER stress decreases the HMW form in serum, contributing to the development of insulin resistance and Type 2 diabetes. In this study, a panel of synthetic peptides, designed to target ERp44-adiponectin interactions, were tested for their effects on circulating levels of HMW adiponectin. EXPERIMENTAL APPROACH Peptides derived from the ERp44 binding region of adiponectin and immunoglobulin IgM were synthesized with or without a cell-penetrating sequence. Cultures of 3T3-L1 adipocytes were incubated with the peptides for assessing the assembly and secretion of HMW adiponectin. Mice given standard chow or a high-fat diet were treated acutely or chronically, with the peptides to investigate the therapeutic effects on insulin sensitivity and energy metabolism. RESULTS The designed peptides interfered with ERp44-adiponectin interactions and modulated adiponectin assembly and release from adipocytes. In particular, IgM-derived peptides facilitated the release of endogenous adiponectin (especially the HMW form) from adipose tissue, enhanced its circulating level and the ratio of HMW-to-total-adiponectin in obese mice. Long-term treatment of mice fed with high-fat diet by IgM-derived peptides reduced the circulating lipid levels and improved insulin sensitivity. CONCLUSIONS AND IMPLICATIONS Targeting ERp44-adiponectin interactions with short peptides represents an effective strategy to treat of obesity-related metabolic disorders, such as insulin resistance and Type 2 diabetes.
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Affiliation(s)
- Lutz Hampe
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Cheng Xu
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong
| | - Paul W R Harris
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Jie Chen
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong
| | - Ming Liu
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong
| | - Martin Middleditch
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Mazdak Radjainia
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Yu Wang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong
| | - Alok K Mitra
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
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27
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Abstract
Cysteine thiols are among the most reactive functional groups in proteins, and their pairing in disulfide linkages is a common post-translational modification in proteins entering the secretory pathway. This modest amino acid alteration, the mere removal of a pair of hydrogen atoms from juxtaposed cysteine residues, contrasts with the substantial changes that characterize most other post-translational reactions. However, the wide variety of proteins that contain disulfides, the profound impact of cross-linking on the behavior of the protein polymer, the numerous and diverse players in intracellular pathways for disulfide formation, and the distinct biological settings in which disulfide bond formation can take place belie the simplicity of the process. Here we lay the groundwork for appreciating the mechanisms and consequences of disulfide bond formation in vivo by reviewing chemical principles underlying cysteine pairing and oxidation. We then show how enzymes tune redox-active cofactors and recruit oxidants to improve the specificity and efficiency of disulfide formation. Finally, we discuss disulfide bond formation in a cellular context and identify important principles that contribute to productive thiol oxidation in complex, crowded, dynamic environments.
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Affiliation(s)
- Deborah Fass
- Department of Structural Biology, Weizmann Institute of Science , Rehovot 7610001, Israel
| | - Colin Thorpe
- Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716, United States
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