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Jaskolowski M, Jomaa A, Gamerdinger M, Shrestha S, Leibundgut M, Deuerling E, Ban N. Molecular basis of the TRAP complex function in ER protein biogenesis. Nat Struct Mol Biol 2023:10.1038/s41594-023-00990-0. [PMID: 37170030 DOI: 10.1038/s41594-023-00990-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 04/06/2023] [Indexed: 05/13/2023]
Abstract
The translocon-associated protein (TRAP) complex resides in the endoplasmic reticulum (ER) membrane and interacts with the Sec translocon and the ribosome to facilitate biogenesis of secretory and membrane proteins. TRAP plays a key role in the secretion of many hormones, including insulin. Here we reveal the molecular architecture of the mammalian TRAP complex and how it engages the translating ribosome associated with Sec61 translocon on the ER membrane. The TRAP complex is anchored to the ribosome via a long tether and its position is further stabilized by a finger-like loop. This positions a cradle-like lumenal domain of TRAP below the translocon for interactions with translocated nascent chains. Our structure-guided TRAP mutations in Caenorhabditis elegans lead to growth deficits associated with increased ER stress and defects in protein hormone secretion. These findings elucidate the molecular basis of the TRAP complex in the biogenesis and translocation of proteins at the ER.
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Affiliation(s)
- Mateusz Jaskolowski
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Ahmad Jomaa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
- Department of Molecular Physiology and Biological Physics and the Center for Cell and Membrane Physiology, University of Virginia, Charlottesville, VA, USA.
| | - Martin Gamerdinger
- Department of Biology, Molecular Microbiology, University of Konstanz, Konstanz, Germany
| | - Sandeep Shrestha
- Department of Biology, Molecular Microbiology, University of Konstanz, Konstanz, Germany
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Elke Deuerling
- Department of Biology, Molecular Microbiology, University of Konstanz, Konstanz, Germany.
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
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2
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Healing the Broken Hearts: A Glimpse on Next Generation Therapeutics. HEARTS 2022. [DOI: 10.3390/hearts3040013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cardiovascular diseases are the leading cause of death worldwide, accounting for 32% of deaths globally and thus representing almost 18 million people according to WHO. Myocardial infarction, the most prevalent adult cardiovascular pathology, affects over half a million people in the USA according to the last records of the AHA. However, not only adult cardiovascular diseases are the most frequent diseases in adulthood, but congenital heart diseases also affect 0.8–1.2% of all births, accounting for mild developmental defects such as atrial septal defects to life-threatening pathologies such as tetralogy of Fallot or permanent common trunk that, if not surgically corrected in early postnatal days, they are incompatible with life. Therefore, both congenital and adult cardiovascular diseases represent an enormous social and economic burden that invariably demands continuous efforts to understand the causes of such cardiovascular defects and develop innovative strategies to correct and/or palliate them. In the next paragraphs, we aim to briefly account for our current understanding of the cellular bases of both congenital and adult cardiovascular diseases, providing a perspective of the plausible lines of action that might eventually result in increasing our understanding of cardiovascular diseases. This analysis will come out with the building blocks for designing novel and innovative therapeutic approaches to healing the broken hearts.
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3
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Preston CC, Stoddard AC, Faustino RS. A Transient Mystery: Nucleolar Channel Systems. Results Probl Cell Differ 2022; 70:581-593. [PMID: 36348122 DOI: 10.1007/978-3-031-06573-6_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The nucleus is a complex organelle with functions beyond being a simple repository for genomic material. For example, its actions in biomechanical sensing, protein synthesis, and epigenomic regulation showcase how the nucleus integrates multiple signaling modalities to intricately regulate gene expression. This innate dynamism is underscored by subnuclear components that facilitate these roles, with elements of the nucleoskeleton, phase-separated nuclear bodies, and chromatin safeguarding by nuclear envelope proteins providing examples of this functional diversity. Among these, one of the lesser characterized nuclear organelles is the nucleolar channel system (NCS), first reported several decades ago in human endometrial biopsies. This tubular structure, believed to be derived from the inner nuclear membrane of the nuclear envelope, was first observed in secretory endometrial cells during a specific phase of the menstrual cycle. Reported as a consistent, yet transient, nuclear organelle, current interpretations of existing data suggest that it serves as a marker of a window for optimal implantation. In spite of this available data, the NCS remains incompletely characterized structurally and functionally, due in part to its transient spatial and temporal expression. As a further complication, evidence exists showing NCS expression in fetal tissue, suggesting that it may not act exclusively as a marker of uterine receptivity, but rather as a hormone sensor sensitive to estrogen and progesterone ratios. To gain a better understanding of the NCS, current technologies can be applied to profile rare cell populations or capture transient structural dynamics, for example, at a level of sensitivity and resolution not previously possible. Moving forward, advanced characterization of the NCS will shed light on an uncharacterized aspect of reproductive physiology, with the potential to refine assisted reproductive techniques.
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Affiliation(s)
- Claudia C Preston
- Biology Department, St. Mary's University of Minnesota, Winona, MN, USA
| | | | - Randolph S Faustino
- Genetics and Genomics Group, Sanford Research, Sioux Falls, SD, USA.
- Department of Pediatrics, Sanford School of Medicine of the University of South Dakota, Sioux Falls, SD, USA.
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4
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Dong A, Yang Y, Liu S, Zenda T, Liu X, Wang Y, Li J, Duan H. Comparative proteomics analysis of two maize hybrids revealed drought-stress tolerance mechanisms. BIOTECHNOL BIOTEC EQ 2020. [DOI: 10.1080/13102818.2020.1805015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Affiliation(s)
- Anyi Dong
- Department of Crop Genetics and Breeding, College of Agronomy, Hebei Agricultural University, Baoding, Hebei, PR China
- North China Key Laboratory for Crop Germplasm Resources of the Education Ministry, Hebei Agricultural University, Baoding, Hebei, PR China
| | - Yatong Yang
- Department of Crop Genetics and Breeding, College of Agronomy, Hebei Agricultural University, Baoding, Hebei, PR China
- North China Key Laboratory for Crop Germplasm Resources of the Education Ministry, Hebei Agricultural University, Baoding, Hebei, PR China
| | - Songtao Liu
- Department of Crop Genetics and Breeding, College of Agronomy, Hebei Agricultural University, Baoding, Hebei, PR China
- North China Key Laboratory for Crop Germplasm Resources of the Education Ministry, Hebei Agricultural University, Baoding, Hebei, PR China
| | - Tinashe Zenda
- Department of Crop Genetics and Breeding, College of Agronomy, Hebei Agricultural University, Baoding, Hebei, PR China
- North China Key Laboratory for Crop Germplasm Resources of the Education Ministry, Hebei Agricultural University, Baoding, Hebei, PR China
| | - Xinyue Liu
- Department of Crop Genetics and Breeding, College of Agronomy, Hebei Agricultural University, Baoding, Hebei, PR China
- North China Key Laboratory for Crop Germplasm Resources of the Education Ministry, Hebei Agricultural University, Baoding, Hebei, PR China
| | - Yafei Wang
- Department of Crop Genetics and Breeding, College of Agronomy, Hebei Agricultural University, Baoding, Hebei, PR China
- North China Key Laboratory for Crop Germplasm Resources of the Education Ministry, Hebei Agricultural University, Baoding, Hebei, PR China
| | - Jiao Li
- Department of Crop Genetics and Breeding, College of Agronomy, Hebei Agricultural University, Baoding, Hebei, PR China
- North China Key Laboratory for Crop Germplasm Resources of the Education Ministry, Hebei Agricultural University, Baoding, Hebei, PR China
| | - Huijun Duan
- Department of Crop Genetics and Breeding, College of Agronomy, Hebei Agricultural University, Baoding, Hebei, PR China
- North China Key Laboratory for Crop Germplasm Resources of the Education Ministry, Hebei Agricultural University, Baoding, Hebei, PR China
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Abstract
In eukaryotic cells, about one-third of the synthesized proteins are translocated into the endoplasmic reticulum; they are membrane or lumen resident proteins and proteins direct to the Golgi apparatus. The co-translational translocation takes place through the heterotrimeric protein-conducting channel Sec61 which is associated with the ribosome and many accessory components, such as the heterotetrameric translocon-associated protein (TRAP) complex. Recently, microscopic techniques, such as cryo-electron microscopy and cryo-electron tomography, have enabled the determination of the translocation machinery structure. However, at present, there is a lack of understanding regarding the roles of some of its components; indeed, the TRAP complex function during co-translational translocation needs to be established. In addition, TRAP may play a role during unfolded protein response, endoplasmic-reticulum-associated protein degradation and congenital disorder of glycosylation (ssr4 CDG). In this article, I describe the current understanding of the TRAP complex in the light of its possible function(s).
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Affiliation(s)
- Antonietta Russo
- Medical Biochemistry and Molecular Biology, UKS, University of Saarland, Homburg, Germany
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6
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Li X, Itani OA, Haataja L, Dumas KJ, Yang J, Cha J, Flibotte S, Shih HJ, Delaney CE, Xu J, Qi L, Arvan P, Liu M, Hu PJ. Requirement for translocon-associated protein (TRAP) α in insulin biogenesis. SCIENCE ADVANCES 2019; 5:eaax0292. [PMID: 31840061 PMCID: PMC6892615 DOI: 10.1126/sciadv.aax0292] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 10/07/2019] [Indexed: 05/26/2023]
Abstract
The mechanistic basis for the biogenesis of peptide hormones and growth factors is poorly understood. Here, we show that the conserved endoplasmic reticulum membrane translocon-associated protein α (TRAPα), also known as signal sequence receptor 1, plays a critical role in the biosynthesis of insulin. Genetic analysis in the nematode Caenorhabditis elegans and biochemical studies in pancreatic β cells reveal that TRAPα deletion impairs preproinsulin translocation while unexpectedly disrupting distal steps in insulin biogenesis including proinsulin processing and secretion. The association of common intronic single-nucleotide variants in the human TRAPα gene with susceptibility to type 2 diabetes and pancreatic β cell dysfunction suggests that impairment of preproinsulin translocation and proinsulin trafficking may contribute to the pathogenesis of type 2 diabetes.
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Affiliation(s)
- Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Omar A. Itani
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Leena Haataja
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kathleen J. Dumas
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jing Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jeeyeon Cha
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Division of Diabetes, Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Stephane Flibotte
- Departments of Zoology and Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hung-Jen Shih
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Colin E. Delaney
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jialu Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ling Qi
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter Arvan
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Patrick J. Hu
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN, USA
- Division of Hematology and Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
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Zhang C, Shi S. Physiological and Proteomic Responses of Contrasting Alfalfa ( Medicago sativa L.) Varieties to PEG-Induced Osmotic Stress. FRONTIERS IN PLANT SCIENCE 2018; 9:242. [PMID: 29541085 PMCID: PMC5835757 DOI: 10.3389/fpls.2018.00242] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 02/12/2018] [Indexed: 05/23/2023]
Abstract
Drought severely limits global plant distribution and agricultural production. Elucidating the physiological and molecular mechanisms governing alfalfa stress responses will contribute to the improvement of drought tolerance in leguminous crops. In this study, the physiological and proteomic responses of two alfalfa (Medicago sativa L.) varieties contrasting in drought tolerance, Longzhong (drought-tolerant) and Gannong No. 3 (drought-sensitive), were comparatively assayed when seedlings were exposed to -1.2 MPa polyethylene glycol (PEG-6000) treatments for 15 days. The results showed that the levels of proline, malondialdehyde (MDA), hydrogen peroxide (H2O2), hydroxyl free radical (OH•) and superoxide anion free radical (O2•-) in both varieties were significantly increased, while the root activity, the superoxide dismutase (SOD) and glutathione reductase (GR) activities, and the ratios of reduced/oxidized ascorbate (AsA/DHA) and reduced/oxidized glutathione (GSH/GSSG) were significantly decreased. The soluble protein and soluble sugar contents, the total antioxidant capability (T-AOC) and the activities of peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) first increased and then decreased with the increase in treatment days. Under osmotic stress, Longzhong exhibited lower levels of MDA, H2O2, OH• and O2•- but higher levels of SOD, CAT, APX, T-AOC and ratios of AsA/DHA and GSH/GSSG compared with Gannong No.3. Using isobaric tags for relative and absolute quantification (iTRAQ), 142 differentially accumulated proteins (DAPs) were identified from two alfalfa varieties, including 52 proteins (34 up-regulated and 18 down-regulated) in Longzhong, 71 proteins (28 up-regulated and 43 down-regulated) in Gannong No. 3, and 19 proteins (13 up-regulated and 6 down-regulated) shared by both varieties. Most of these DAPs were involved in stress and defense, protein metabolism, transmembrane transport, signal transduction, as well as cell wall and cytoskeleton metabolism. In conclusion, the stronger drought-tolerance of Longzhong was attributed to its higher osmotic adjustment capacity, greater ability to orchestrate its enzymatic and non-enzymatic antioxidant systems and thus avoid great oxidative damage in comparison to Gannong No. 3. Moreover, the involvement of other pathways, including carbohydrate metabolism, ROS detoxification, secondary metabolism, protein processing, ion and water transport, signal transduction, and cell wall adjustment, are important mechanisms for conferring drought tolerance in alfalfa.
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Affiliation(s)
- Cuimei Zhang
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Pratacultural Engineering Laboratory of Gansu Province, Sino-U.S. Centers for Grazing Land Ecosystem Sustainability, Gansu Agricultural University, Lanzhou, China
| | - Shangli Shi
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Pratacultural Engineering Laboratory of Gansu Province, Sino-U.S. Centers for Grazing Land Ecosystem Sustainability, Gansu Agricultural University, Lanzhou, China
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8
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Bañó-Polo M, Martínez-Garay CA, Grau B, Martínez-Gil L, Mingarro I. Membrane insertion and topology of the translocon-associated protein (TRAP) gamma subunit. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:903-909. [PMID: 28132902 DOI: 10.1016/j.bbamem.2017.01.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/19/2017] [Accepted: 01/25/2017] [Indexed: 12/20/2022]
Abstract
Translocon-associated protein (TRAP) complex is intimately associated with the ER translocon for the insertion or translocation of newly synthesised proteins in eukaryotic cells. The TRAP complex is comprised of three single-spanning and one multiple-spanning subunits. We have investigated the membrane insertion and topology of the multiple-spanning TRAP-γ subunit by glycosylation mapping and green fluorescent protein fusions both in vitro and in cell cultures. Results demonstrate that TRAP-γ has four transmembrane (TM) segments, an Nt/Ct cytosolic orientation and that the less hydrophobic TM segment inserts efficiently into the membrane only in the cellular context of full-length protein.
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Affiliation(s)
- Manuel Bañó-Polo
- Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain
| | - Carlos A Martínez-Garay
- Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain
| | - Brayan Grau
- Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain
| | - Luis Martínez-Gil
- Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain
| | - Ismael Mingarro
- Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain.
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9
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Garg B, Pathria G, Wagner C, Maurer M, Wagner SN. Signal Sequence Receptor 2 is required for survival of human melanoma cells as part of an unfolded protein response to endoplasmic reticulum stress. Mutagenesis 2016; 31:573-82. [PMID: 27180333 DOI: 10.1093/mutage/gew023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Current therapy approaches in melanoma targeting have met with the development of resistance and tumour recurrence with a more aggressive phenotype. In a quest for alternative therapy targets, we had previously identified Signal Sequence Receptor 2 (SSR2) as a gene with high expression in a subgroup of human primary melanomas. Now we show that SSR2 exerts a prosurvival functionality in human melanoma cells and that high expression levels of SSR2 are associated with an unfavourable disease outcome in primary melanoma patients. Consistent with SSR's role in translocation of proteins from the ribosome across the endoplasmic reticulum (ER) membrane, our data supports induction of SSR2 as a part of the ER stress response. This response included SSR2 upregulation upon development of therapy resistance to BRAF inhibitors, as well as the dependency of cell survival of BRAF inhibitor-resistant melanoma cells on SSR2. Complementary gain and loss of function data showed the Unfolded Protein Response (UPR) to ER stress as an inducer of SSR2 via transcriptional regulation through X-Box Binding Protein 1s (XBP1s) and support an ER stress-UPR-Transcription Factor XBP1s-SSR2 response axis in human melanocytic cells. Together with its dispensability for survival in normal human cells, these data propose SSR2 as a potential therapeutic target in (therapy-resistant) human melanoma.
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Affiliation(s)
- Bhavuk Garg
- Division of Immunology Allergy and Infectious Diseases (DIAID), Department of Dermatology, Medical University of Vienna, Waehringer Guertel 18-20, Vienna A-1090, Austria
| | - Gaurav Pathria
- Division of Immunology Allergy and Infectious Diseases (DIAID), Department of Dermatology, Medical University of Vienna, Waehringer Guertel 18-20, Vienna A-1090, Austria, Present address: Biochemical-Pharmacological Center, University of Marburg, Karl-von-Frisch-Straße, Marburg 35032, Germany
| | - Christine Wagner
- Division of Immunology Allergy and Infectious Diseases (DIAID), Department of Dermatology, Medical University of Vienna, Waehringer Guertel 18-20, Vienna A-1090, Austria
| | - Margarita Maurer
- Division of Immunology Allergy and Infectious Diseases (DIAID), Department of Dermatology, Medical University of Vienna, Waehringer Guertel 18-20, Vienna A-1090, Austria
| | - Stephan N Wagner
- Division of Immunology Allergy and Infectious Diseases (DIAID), Department of Dermatology, Medical University of Vienna, Waehringer Guertel 18-20, Vienna A-1090, Austria,
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10
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Genes regulating lipid and protein metabolism are highly expressed in mammary gland of lactating dairy goats. Funct Integr Genomics 2014; 15:309-21. [PMID: 25433708 DOI: 10.1007/s10142-014-0420-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 11/17/2014] [Accepted: 11/20/2014] [Indexed: 10/24/2022]
Abstract
Dairy goats serve as an important source of milk and also fulfill agricultural and economic roles in developing countries. Understanding the genetic background of goat mammary gland is important for research on the regulatory mechanisms controlling tissue function and the synthesis of milk components. We collected tissue at four different stages of goat mammary gland development and generated approximately 25 GB of data from Illumina de novo RNA sequencing. The combined reads were assembled into 51,361 unigenes, and approximately 60.07 % of the unigenes had homology to other proteins in the NCBI non-redundant protein database (NR). Functional classification through eukaryotic Ortholog Groups of Protein (KOG), gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that the unigenes from goat mammary glands are involved in a wide range of biological processes and metabolic pathways, including lipid metabolism and lactose metabolism. The results of qPCR revealed that genes encoding FABP3, FASN, SCD, PLIN2, whey proteins (LALBA and BLG), and caseins (CSN1S1, CSN1S2, CSN2 and CSN3) at 100 and 310 days postpartum increased significantly compared with the non-lactating period. In addition to their role in lipid and protein synthesis, the higher expression at 310 days postpartum could contribute to mammary cell turnover during pregnancy. In conclusion, this is the first study to characterize the complete transcriptome of goat mammary glands and constitutes a comprehensive genomic resource available for further studies of ruminant lactation.
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11
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Rodrigo-Brenni MC, Gutierrez E, Hegde RS. Cytosolic quality control of mislocalized proteins requires RNF126 recruitment to Bag6. Mol Cell 2014; 55:227-37. [PMID: 24981174 PMCID: PMC4104027 DOI: 10.1016/j.molcel.2014.05.025] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 04/07/2014] [Accepted: 05/06/2014] [Indexed: 01/22/2023]
Abstract
Approximately 30% of eukaryotic proteins contain hydrophobic signals for localization to the secretory pathway. These proteins can be mislocalized in the cytosol due to mutations in their targeting signals, certain stresses, or intrinsic inefficiencies in their translocation. Mislocalized proteins (MLPs) are protected from aggregation by the Bag6 complex and degraded by a poorly characterized proteasome-dependent pathway. Here, we identify the ubiquitin ligase RNF126 as a key component of the MLP degradation pathway. In vitro reconstitution and fractionation studies reveal that RNF126 is the primary Bag6-dependent ligase. RNF126 is recruited to the N-terminal Ubl domain of Bag6 and preferentially ubiquitinates juxtahydrophobic lysine residues on Bag6-associated clients. Interfering with RNF126 recruitment in vitro prevents ubiquitination, and RNF126 depletion in cells partially stabilizes a Bag6 client. Bag6-dependent ubiquitination can be recapitulated with purified components, paving the way for mechanistic analyses of downstream steps in this cytosolic quality control pathway. The chaperone Bag6 recruits the ubiquitin ligase RNF126 to its Ubl domain RNF126 is necessary and sufficient for optimal ubiquitination of Bag6 clients Purified Bag6-client complex supports ubiquitination by recombinant RNF126 Bag6-associated mislocalized protein is stabilized by loss of RNF126 in cells
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Affiliation(s)
| | - Erik Gutierrez
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ramanujan S Hegde
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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12
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Chen HZ, Wen Q, Wang WJ, He JP, Wu Q. The orphan nuclear receptor TR3/Nur77 regulates ER stress and induces apoptosis via interaction with TRAPγ. Int J Biochem Cell Biol 2013; 45:1600-9. [PMID: 23660295 DOI: 10.1016/j.biocel.2013.04.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 04/11/2013] [Accepted: 04/29/2013] [Indexed: 12/09/2022]
Abstract
The orphan nuclear receptor TR3 (also known as Nur77) belongs to the steroid/thyroid/retinoid nuclear receptor superfamily and plays important roles in regulating cell proliferation, differentiation and apoptosis. No physiological ligand for TR3 has been found thus far; the determination of its binding partners is therefore important to clarify the biological functions of TR3. Here, we identified translocon-associated protein subunit γ (TRAPγ) as a novel TR3 binding partner using a tandem affinity purification method. This interaction between TR3 and TRAPγ was further confirmed, and the interacting regions were mapped. The ligand-binding domain of TR3 was required for TRAPγ binding, and the C terminus of TRAPγ was responsible for its interaction with TR3. When stimulated with 12-O-tetradecanoylphorbol 13-acetate (TPA) or CD437, this TR3-TRAPγ interaction not only induced Ca(2+) depletion in the endoplasmic reticulum (ER) but also promoted the expression of the proapoptotic transcriptional regulator CHOP. Notably, both TR3 and TRAPγ were required for ER stress-induced apoptosis in HepG2 cells. Overall, this study demonstrated a novel, TR3-initiated signaling pathway in which TR3 regulates ER stress and induces apoptosis of hepatoma cells through its interaction with TRAPγ.
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Affiliation(s)
- Hang-zi Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, Fujian Province, PR China.
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13
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Diring J, Camuzeaux B, Donzeau M, Vigneron M, Rosa-Calatrava M, Kedinger C, Chatton B. A cytoplasmic negative regulator isoform of ATF7 impairs ATF7 and ATF2 phosphorylation and transcriptional activity. PLoS One 2011; 6:e23351. [PMID: 21858082 PMCID: PMC3156760 DOI: 10.1371/journal.pone.0023351] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 07/13/2011] [Indexed: 11/18/2022] Open
Abstract
Alternative splicing and post-translational modifications are processes that give rise to the complexity of the proteome. The nuclear ATF7 and ATF2 (activating transcription factor) are structurally homologous leucine zipper transcription factors encoded by distinct genes. Stress and growth factors activate ATF2 and ATF7 mainly via sequential phosphorylation of two conserved threonine residues in their activation domain. Distinct protein kinases, among which mitogen-activated protein kinases (MAPK), phosphorylate ATF2 and ATF7 first on Thr71/Thr53 and next on Thr69/Thr51 residues respectively, resulting in transcriptional activation. Here, we identify and characterize a cytoplasmic alternatively spliced isoform of ATF7. This variant, named ATF7-4, inhibits both ATF2 and ATF7 transcriptional activities by impairing the first phosphorylation event on Thr71/Thr53 residues. ATF7-4 indeed sequesters the Thr53-phosphorylating kinase in the cytoplasm. Upon stimulus-induced phosphorylation, ATF7-4 is poly-ubiquitinated and degraded, enabling the release of the kinase and ATF7/ATF2 activation. Our data therefore conclusively establish that ATF7-4 is an important cytoplasmic negative regulator of ATF7 and ATF2 transcription factors.
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Affiliation(s)
- Jessica Diring
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, BP10413, Illkirch, France
| | - Barbara Camuzeaux
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, BP10413, Illkirch, France
| | - Mariel Donzeau
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, BP10413, Illkirch, France
| | - Marc Vigneron
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, BP10413, Illkirch, France
| | - Manuel Rosa-Calatrava
- Laboratoire de Virologie et Pathologie Humaine VirPath, Université Claude Bernard Lyon 1, Hospices Civils de Lyon, Lyon, France
| | - Claude Kedinger
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, BP10413, Illkirch, France
| | - Bruno Chatton
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, BP10413, Illkirch, France
- * E-mail:
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14
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Yamaguchi YL, Tanaka SS, Oshima N, Kiyonari H, Asashima M, Nishinakamura R. Translocon-associated protein subunit Trap-γ/Ssr3 is required for vascular network formation in the mouse placenta. Dev Dyn 2011; 240:394-403. [DOI: 10.1002/dvdy.22528] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2010] [Indexed: 12/12/2022] Open
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15
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Rochais F, Dandonneau M, Mesbah K, Jarry T, Mattei MG, Kelly RG. Hes1 is expressed in the second heart field and is required for outflow tract development. PLoS One 2009; 4:e6267. [PMID: 19609448 PMCID: PMC2707624 DOI: 10.1371/journal.pone.0006267] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 06/12/2009] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Rapid growth of the embryonic heart occurs by addition of progenitor cells of the second heart field to the poles of the elongating heart tube. Failure or perturbation of this process leads to congenital heart defects. In order to provide further insight into second heart field development we characterized the insertion site of a transgene expressed in the second heart field and outflow tract as the result of an integration site position effect. RESULTS Here we show that the integration site of the A17-Myf5-nlacZ-T55 transgene lies upstream of Hes1, encoding a basic helix-loop-helix containing transcriptional repressor required for the maintenance of diverse progenitor cell populations during embryonic development. Transgene expression in a subset of Hes1 expression sites, including the CNS, pharyngeal epithelia, pericardium, limb bud and lung endoderm suggests that Hes1 is the endogenous target of regulatory elements trapped by the transgene. Hes1 is expressed in pharyngeal endoderm and mesoderm including the second heart field. Analysis of Hes1 mutant hearts at embryonic day 15.5 reveals outflow tract alignment defects including ventricular septal defects and overriding aorta. At earlier developmental stages, Hes1 mutant embryos display defects in second heart field proliferation, a reduction in cardiac neural crest cells and failure to completely extend the outflow tract. CONCLUSIONS Hes1 is expressed in cardiac progenitor cells in the early embryo and is required for development of the arterial pole of the heart.
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Affiliation(s)
- Francesca Rochais
- Developmental Biology Institute of Marseilles-Luminy, UMR 6216 CNRS-Université de la Méditerranée, Campus de Luminy, Marseille, France
| | - Mathieu Dandonneau
- Developmental Biology Institute of Marseilles-Luminy, UMR 6216 CNRS-Université de la Méditerranée, Campus de Luminy, Marseille, France
| | - Karim Mesbah
- Developmental Biology Institute of Marseilles-Luminy, UMR 6216 CNRS-Université de la Méditerranée, Campus de Luminy, Marseille, France
| | - Thérèse Jarry
- Developmental Biology Institute of Marseilles-Luminy, UMR 6216 CNRS-Université de la Méditerranée, Campus de Luminy, Marseille, France
| | | | - Robert G. Kelly
- Developmental Biology Institute of Marseilles-Luminy, UMR 6216 CNRS-Université de la Méditerranée, Campus de Luminy, Marseille, France
- * E-mail:
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Abstract
Biological processes are regulated to provide cells with exquisite adaptability to changing environmental conditions and cellular demands. The mechanisms regulating secretory and membrane protein translocation into the endoplasmic reticulum (ER) are unknown. A conceptual framework for translocational regulation is proposed based on our current mechanistic understanding of ER protein translocation and general principles of regulatory control.
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Affiliation(s)
- Ramanujan S Hegde
- Cell Biology and Metabolism Program, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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