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Masuda R, Karasaki T, Sase S, Kuwano S, Goto K. Highly Electrophilic Intermediates in the Bypass Mechanism of Glutathione Peroxidase: Synthesis, Reactivity, and Structures of Selenocysteine-Derived Cyclic Selenenyl Amides. Chemistry 2023; 29:e202302615. [PMID: 37738074 DOI: 10.1002/chem.202302615] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/14/2023] [Accepted: 09/19/2023] [Indexed: 09/23/2023]
Abstract
Selenocysteine (Sec)-derived cyclic selenenyl amides, formed by the intramolecular cyclization of Sec selenenic acids (Sec-SeOHs), have been postulated to function as protective forms in the bypass mechanism of glutathione peroxidase (GPx). However, their chemical properties have not been experimentally elucidated in proteins or small-molecule systems. Recently, we reported the first nuclear magnetic resonance observation of Sec-SeOHs and their cyclization to the corresponding cyclic selenenyl amides by using selenopeptide model systems incorporated in a molecular cradle. Herein, we elucidate the structures and reactivities of Sec-derived cyclic selenenyl amides. The crystal structures and reactions toward a cysteine thiol or a 1,3-diketone-type chemical probe indicated the highly electrophilic character of cyclic selenenyl amides. This suggests that they can serve not only as protective forms to suppress the inactivation of Sec-SeOHs in GPx but also as highly electrophilic intermediates in the reactions of selenoproteins.
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Affiliation(s)
- Ryosuke Masuda
- School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Takafumi Karasaki
- School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Shohei Sase
- School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Satoru Kuwano
- School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Kei Goto
- School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
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2
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Ke J, Zhang DG, Lei XJ, Liu GH, Luo Z. Characterization and tissue expression of twelve selenoproteins in yellow catfish Pelteobagrus fulvidraco fed diets varying in oxidized fish oil and selenium levels. J Trace Elem Med Biol 2023; 79:127204. [PMID: 37244044 DOI: 10.1016/j.jtemb.2023.127204] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 04/28/2023] [Accepted: 05/14/2023] [Indexed: 05/29/2023]
Abstract
BACKGROUND Selenium (Se) functions through selenoproteins and is essential to growth and metabolism of vertebrates. The present study was conducted to identify twelve selenoproteins genes (selenoe, selenof, selenoh, selneoi, selenom, selenok, selneon, selenoo, selenot, selenos, selenou and msrb1) from yellow catfish. Their mRNA expression patterns, as well as their response to dietary oxidized fish oils and Se addition were explored. METHODS We use 3'and 5' RACE PCR to clone full-length cDNA sequence of twelve selenoprotein genes from yellow catfish. Their mRNA expression patterns were assessed via quantitative real-time PCR. Yellow catfish were fed diet adequate Se+ fresh fish oil, adequate Se+ oxidized fish oil, high Se+ fresh fish oil and high Se+ oxidized fish oil, respectively, for 10 weeks. Their kidney, heart, brain and testis were used to assess the mRNA expression of twelve selenoprotein. RESULTS Twelve selenoprotein genes had similar domains with mammals and the other fish. Their mRNAs were expressed widely in eleven tissues but varied with the tissues. Dietary oxidized fish oils and Se addition influenced their mRNA abundances of twelve selenoproteins in a tissue-dependent manner. CONCLUSION Our study demonstrated the characterization and expression of twelve selenoproteins, and elucidated their responses in yellow catfish fed diets varying in oxidized fish oils and Se addition, which increased our knowledge into the biological function and regulatory mechanism of Se and selenoproteins in fish.
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Affiliation(s)
- Jiang Ke
- Hubei Hongshan Laboratory, Fishery College, Huazhong Agriculture University, Wuhan 430070, China
| | - Dian-Guang Zhang
- Hubei Hongshan Laboratory, Fishery College, Huazhong Agriculture University, Wuhan 430070, China
| | - Xi-Jun Lei
- Hubei Hongshan Laboratory, Fishery College, Huazhong Agriculture University, Wuhan 430070, China
| | - Guang-Hui Liu
- Hubei Hongshan Laboratory, Fishery College, Huazhong Agriculture University, Wuhan 430070, China
| | - Zhi Luo
- Hubei Hongshan Laboratory, Fishery College, Huazhong Agriculture University, Wuhan 430070, China; Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, China; Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.
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3
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Ghelichkhani F, Gonzalez FA, Kapitonova MA, Schaefer-Ramadan S, Liu J, Cheng R, Rozovsky S. Selenoprotein S: A versatile disordered protein. Arch Biochem Biophys 2022; 731:109427. [PMID: 36241082 PMCID: PMC10026367 DOI: 10.1016/j.abb.2022.109427] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/16/2022]
Abstract
Selenoprotein S (selenos) is a small, intrinsically disordered membrane protein that is associated with various cellular functions, such as inflammatory processes, cellular stress response, protein quality control, and signaling pathways. It is primarily known for its contribution to the ER-associated degradation (ERAD) pathway, which governs the extraction of misfolded proteins or misassembled protein complexes from the ER to the cytosol for degradation by the proteasome. However, selenos's other cellular roles in signaling are equally vital, including the control of transcription factors and cytokine levels. Consequently, genetic polymorphisms of selenos are associated with increased risk for diabetes, dyslipidemia, and cardiovascular diseases, while high expression levels correlate with poor prognosis in several cancers. Its inhibitory role in cytokine secretion is also exploited by viruses. Since selenos binds multiple protein complexes, however, its specific contributions to various cellular pathways and diseases have been difficult to establish. Thus, the precise cellular functions of selenos and their interconnectivity have only recently begun to emerge. This review aims to summarize recent insights into the structure, interactome, and cellular roles of selenos.
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Affiliation(s)
- Farid Ghelichkhani
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Fabio A Gonzalez
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Mariia A Kapitonova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | | | - Jun Liu
- Enlaza Therapeutics, 11099 N. Torrey Pines Rd, suite 290, La Jolla, CA, 92037, USA
| | - Rujin Cheng
- NGM Biopharmaceuticals, Inc., 333 Oyster Point Blvd, South San Francisco, CA, 94080, USA
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA.
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Jehan C, Cartier D, Bucharles C, Anouar Y, Lihrmann I. Emerging roles of ER-resident selenoproteins in brain physiology and physiopathology. Redox Biol 2022; 55:102412. [PMID: 35917681 PMCID: PMC9344019 DOI: 10.1016/j.redox.2022.102412] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/05/2022] [Accepted: 07/14/2022] [Indexed: 12/23/2022] Open
Abstract
The brain has a very high oxygen consumption rate and is particularly sensitive to oxidative stress. It is also the last organ to suffer from a loss of selenium (Se) in case of deficiency. Se is a crucial trace element present in the form of selenocysteine, the 21st proteinogenic amino acid present in selenoproteins, an essential protein family in the brain that participates in redox signaling. Among the most abundant selenoproteins in the brain are glutathione peroxidase 4 (GPX4), which reduces lipid peroxides and prevents ferroptosis, and selenoproteins W, I, F, K, M, O and T. Remarkably, more than half of them are proteins present in the ER and recent studies have shown their involvement in the maintenance of ER homeostasis, glycoprotein folding and quality control, redox balance, ER stress response signaling pathways and Ca2+ homeostasis. However, their molecular functions remain mostly undetermined. The ER is a highly specialized organelle in neurons that maintains the physical continuity of axons over long distances through its continuous distribution from the cell body to the nerve terminals. Alteration of this continuity can lead to degeneration of distal axons and subsequent neuronal death. Elucidation of the function of ER-resident selenoproteins in neuronal pathophysiology may therefore become a new perspective for understanding the pathophysiology of neurological diseases. Here we summarize what is currently known about each of their molecular functions and their impact on the nervous system during development and stress.
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Affiliation(s)
- Cédric Jehan
- Rouen-Normandie University, UNIROUEN, Inserm, U1239, Neuroendocrine, Endocrine and Germinal Differenciation and Communication Laboratory, Mont-Saint-Aignan Cedex, France; Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Dorthe Cartier
- Rouen-Normandie University, UNIROUEN, Inserm, U1239, Neuroendocrine, Endocrine and Germinal Differenciation and Communication Laboratory, Mont-Saint-Aignan Cedex, France; Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Christine Bucharles
- Rouen-Normandie University, UNIROUEN, Inserm, U1239, Neuroendocrine, Endocrine and Germinal Differenciation and Communication Laboratory, Mont-Saint-Aignan Cedex, France; Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Youssef Anouar
- Rouen-Normandie University, UNIROUEN, Inserm, U1239, Neuroendocrine, Endocrine and Germinal Differenciation and Communication Laboratory, Mont-Saint-Aignan Cedex, France; Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Isabelle Lihrmann
- Rouen-Normandie University, UNIROUEN, Inserm, U1239, Neuroendocrine, Endocrine and Germinal Differenciation and Communication Laboratory, Mont-Saint-Aignan Cedex, France; Institute for Research and Innovation in Biomedicine, Rouen, France.
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5
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Masuda R, Kuwano S, Sase S, Bortoli M, Madabeni A, Orian L, Goto K. Model Study on the Catalytic Cycle of Glutathione Peroxidase Utilizing Selenocysteine-Containing Tripeptides: Elucidation of the Protective Bypass Mechanism Involving Selenocysteine Selenenic Acids. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2022. [DOI: 10.1246/bcsj.20220156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ryosuke Masuda
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Satoru Kuwano
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Shohei Sase
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Marco Bortoli
- Institut de Química Computacional i Catàlisi (IQCC) i Departament de Química, Facultat de Ciències, Universitat de Girona, C/M. A. Capmany 69, 17003 Girona, Spain
| | - Andrea Madabeni
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Laura Orian
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Kei Goto
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
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Wang S, Zhao X, Liu Q, Wang Y, Li S, Xu S. Selenoprotein K protects skeletal muscle from damage and is required for satellite cells-mediated myogenic differentiation. Redox Biol 2022; 50:102255. [PMID: 35144051 PMCID: PMC8844831 DOI: 10.1016/j.redox.2022.102255] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/23/2022] [Accepted: 01/28/2022] [Indexed: 12/11/2022] Open
Abstract
The regeneration of adult skeletal muscle after injury is primarily initiated by satellite cells (SCs), but the regulatory mechanisms of cells committed to myogenic differentiation remain poorly explored. Small molecular selenoprotein K (SelK) plays crucial roles in the modulation of endoplasmic reticulum (ER) stress and against oxidative stress. Here, we first showed that SelK expression is activated in myogenic cells during differentiation both in vivo and in vitro. Meanwhile, loss of SelK delayed skeletal muscle regeneration, inhibited the development of myoblasts into myotubes, and was accompanied by reduced expression of myogenic regulatory factors (MRFs). Moreover, ER stress, intracellular reactive oxygen species (ROS), autophagy and apoptosis under myogenesis induction were more severe in SelK-deficient mice and cells than in the corresponding control groups. Supplementation with specific inhibitors to alleviate excessive ER stress or oxidative stress partly rescued the differentiation potential and formation of myotubes. Notably, we demonstrated that Self-mediated regulation of cellular redox status was primarily derived from its subsequent effects on ER stress. Together, our results suggest that SelK protects skeletal muscle from damage and is a crucial regulator of myogenesis.
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Affiliation(s)
- Shengchen Wang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Xia Zhao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Qingqing Liu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Yue Wang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Shu Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China.
| | - Shiwen Xu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China.
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7
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Bedding MJ, Kulkarni SS, Payne RJ. Diselenide-selenoester ligation in the chemical synthesis of proteins. Methods Enzymol 2022; 662:363-399. [PMID: 35101218 DOI: 10.1016/bs.mie.2021.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Peptides and proteins represent an important class of biomolecules responsible for a plethora of structural and functional roles in vivo. Following their translation on the ribosome, the majority of eukaryotic proteins are post-translationally modified, leading to a proteome that is much larger than the number of genes present in a given organism. In order to understand the functional role of a given protein modification, it is necessary to access peptides and proteins bearing homogeneous and site-specific modifications. Accordingly, there has been significant research effort centered on the development of peptide ligation methodologies for the chemical synthesis of modified proteins. In this chapter we outline the discovery and development of a contemporary methodology called the diselenide-selenoester ligation (DSL) that enables the rapid and efficient fusion of peptide fragments to generate synthetic proteins. The practical aspects of using DSL for the preparation of chemically modified peptides and proteins in the laboratory is described. In addition, recent advances in the application of the methodology are outlined, exemplified by the synthesis and biological evaluation of a number of complex protein targets.
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Affiliation(s)
- Max J Bedding
- School of Chemistry, The University of Sydney, Camperdown, NSW, Australia; Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Camperdown, NSW, Australia
| | - Sameer S Kulkarni
- School of Chemistry, The University of Sydney, Camperdown, NSW, Australia; Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Camperdown, NSW, Australia
| | - Richard J Payne
- School of Chemistry, The University of Sydney, Camperdown, NSW, Australia; Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Camperdown, NSW, Australia.
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8
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Masuda R, Goto K. Modeling of selenocysteine-derived reactive intermediates utilizing a nano-sized molecular cavity as a protective cradle. Methods Enzymol 2022; 662:331-361. [PMID: 35101217 DOI: 10.1016/bs.mie.2021.10.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In the biological functions of selenoproteins, various highly reactive species formed by oxidative modification of selenocysteine residues have been postulated to play crucial roles. Representative examples of such species are selenocysteine selenenic acids (Sec-SeOHs) and selenocysteine selenenyl iodides (Sec-SeIs), which have been widely recognized as important intermediates in the catalytic cycle of glutathione peroxidase (GPx) and iodothyronine deiodinase, respectively. However, examples of even spectroscopic observation of Sec-SeOHs and Sec-SeIs in either protein or small-molecule model systems remain elusive so far, most likely due to their notorious instability. For the synthesis of small-molecule model compounds of these reactive species, it is essential to suppress their very facile bimolecular decomposition such as self-condensation and disproportionation. Here we outline a novel method for the synthesis of stable small-molecule model compounds of the selenocysteine-derived reactive species, in which a nano-sized molecular cavity is used as a protective cradle to accommodate the reactive selenocysteine unit. Stabilization by the molecular cradle led to the successful synthesis of Sec-SeOHs, which are stable in solution at low temperatures, and a Sec-SeI, which can be isolated as crystals. The catalytic cycle of GPx was investigated using the NMR-observable Sec-SeOH models, and all the chemical processes proposed for the catalytic cycle of GPx, including the bypass process from Sec-SeOH to the corresponding cyclic selenenyl amide, were experimentally confirmed. Detailed protocols for the syntheses of selenopeptide derivatives bearing the molecular cradle and for the spectroscopic monitoring of their reactions are provided.
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Affiliation(s)
- Ryosuke Masuda
- Department of Chemistry, School of Science, Tokyo Institute of Technology, Tokyo, Japan
| | - Kei Goto
- Department of Chemistry, School of Science, Tokyo Institute of Technology, Tokyo, Japan.
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9
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Li M, Cheng W, Zhang L. Maternal selenium deficiency suppresses proliferation, induces autophagy dysfunction and apoptosis in the placenta of mice. Metallomics 2021; 13:6406492. [PMID: 34669944 DOI: 10.1093/mtomcs/mfab058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/10/2021] [Indexed: 12/16/2022]
Abstract
Selenium deficiency is thought to be associated with the occurrence of gestational complications. However, the underlying mechanism of selenium deficiency impairs placental function remains unclear. In this study, female mice were separately supplemented with a Se-deficient (0.02 mg/kg Se) or control diet (0.2 mg/kg Se) for 12 weeks before mating and throughout gestation. Maternal liver and placentas were collected at embryonic day 15.5 and analyzed for Se content. Oxidative stress status, proliferation capability, autophagy, and apoptosis of the placenta were determined. We found that maternal selenium deficiency decreased placental Se concentration and some antioxidant selenoproteins expressions. The concentrations of catalase and glutathione in selenium-deficient placentas were reduced, along with an increase in hydrogen peroxide (H2O2) content. Selenium deficiency inhibited the expression of proliferating cell nuclear antigen. Autophagosomes, autophagolysosomes, and upregulation of autophagy-related protein microtubule-associated protein 1 light chain 3 alpha II (LC3B), Beclin1, PTEN-induced putative kinase 1 (PINK1), and Parkin were found in the selenium-deficient trophoblasts. Autophagic substrate p62/sequestosome 1 was surprisingly increased, indicating autophagy flux dysfunction. Selenium deficiency increased expressions of B cell leukemia/lymphoma 2 associated X protein (Bax), cleaved caspase-9/-3, and decreased the B cell leukemia/lymphoma 2 (Bcl2) level. Moreover, typical apoptotic ultrastructure and apoptosis-positive cells were observed in the selenium-deficient placenta. Our results suggested that maternal selenium deficiency impaired placental proliferation, induced autophagy dysfunction and apoptosis via increasing oxidative stress, and the Akt/mechanistic target of rapamycin (mTOR) pathway involved in this process. This study revealed a novel mechanism by which maternal selenium deficiency caused impairment of the placenta.
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Affiliation(s)
- Mengdi Li
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China.,Department of Anatomy, Basic Medical College, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Wanpeng Cheng
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Lantian Zhang
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China.,Department of Anatomy, Basic Medical College, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
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10
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Long MJC, Huang KT, Aye Y. The not so identical twins: (dis)similarities between reactive electrophile and oxidant sensing and signaling. Chem Soc Rev 2021; 50:12269-12291. [PMID: 34779447 DOI: 10.1039/d1cs00467k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In this tutorial review, we compare and contrast the chemical mechanisms of electrophile/oxidant sensing, and the molecular mechanisms of signal propagation. We critically analyze biological systems in which these different pathways are believed to be manifest and what the data really mean. Finally, we discuss applications of this knowledge to disease treatment and drug development.
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Affiliation(s)
| | - Kuan-Ting Huang
- Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Yimon Aye
- Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland.
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A novel therapeutic strategy for hepatocellular carcinoma: Immunomodulatory mechanisms of selenium and/or selenoproteins on a shift towards anti-cancer. Int Immunopharmacol 2021; 96:107790. [PMID: 34162153 DOI: 10.1016/j.intimp.2021.107790] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/05/2021] [Accepted: 05/13/2021] [Indexed: 12/24/2022]
Abstract
Selenium (Se) is an essential trace chemical element that is widely distributed worldwide. Se exerts its immunomodulatory and nutritional activities in the human body in the form of selenoproteins. Se has increasingly appeared as a potential trace element associated with many human diseases, including hepatocellular carcinoma (HCC). Recently, increasing evidence has suggested that Se and selenoproteins exert their immunomodulatory effects on HCC by regulating the molecules of oxidative stress, inflammation, immune response, cell proliferation and growth, angiogenesis, signaling pathways, apoptosis, and other processes in vitro cell studies and in vivo animal studies. Se concentrations are generally low in tissues of patients with HCC, such as blood, serum, scalp hair, and toenail. However, Se concentrations were higher in HCC patient tissues after Se supplementation than before supplementation. This review summarizes the significant relationship between Se and HCC, and details the role of Se as a novel immunomodulatory or immunotherapeutic approach against HCC.
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12
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Masuda R, Kimura R, Karasaki T, Sase S, Goto K. Modeling the Catalytic Cycle of Glutathione Peroxidase by Nuclear Magnetic Resonance Spectroscopic Analysis of Selenocysteine Selenenic Acids. J Am Chem Soc 2021; 143:6345-6350. [PMID: 33887135 DOI: 10.1021/jacs.1c02383] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Although selenocysteine selenenic acids (Sec-SeOHs) have been recognized as key intermediates in the catalytic cycle of glutathione peroxidase (GPx), examples of the direct observation of Sec-SeOH in either protein or small-molecule systems have remained elusive so far, mostly due to their instability. Here, we report the first direct spectroscopic (1H and 77Se NMR) evidence for the formation of Sec-SeOH in small-molecule selenocysteine and selenopeptide model systems with a cradle-type protective group. The catalytic cycle of GPx was investigated using NMR-observable Sec-SeOH models. All the hitherto proposed chemical processes, i.e., not only those of the canonical catalytic cycle but also those involved in the bypass mechanism, including the intramolecular cyclization of Sec-SeOH to the corresponding five-membered ring selenenyl amide, were examined in a stepwise manner.
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Affiliation(s)
- Ryosuke Masuda
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Ryutaro Kimura
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Takafumi Karasaki
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Shohei Sase
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Kei Goto
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
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Krivdin LB. Recent advances in computational liquid-phase 77Se NMR. RUSSIAN CHEMICAL REVIEWS 2021. [DOI: 10.1070/rcr4960] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This review aims to highlight significant progress in the calculation of 77Se NMR chemical shifts and spin – spin coupling constants involving selenium substantiated with a vast amount of experimental data. The material is arranged in two basic sections: the first one dealing with the calculation of 77Se NMR chemical shifts and the second one dealing with the computation of spin – spin coupling constants involving 77Se nucleus, namely 77Se–1H, 77Se–13C and 77Se–77Se together with some more exotic types of couplings, 77Se – 15N, 77Se–19F, 77Se–29Si and 77Se–31P. A special attention is focused on the stereoelectronic effects involving selenium atom and their manifestation in the 77Se NMR spectra of organoselenium compounds studied with the aid of the modern calculation of 77Se NMR parametres in combination with experimental results.
The bibliography includes 114 references.
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14
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Integrated Analysis to Study the Relationship between Tumor-Associated Selenoproteins: Focus on Prostate Cancer. Int J Mol Sci 2020; 21:ijms21186694. [PMID: 32933107 PMCID: PMC7555134 DOI: 10.3390/ijms21186694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/07/2020] [Accepted: 09/11/2020] [Indexed: 11/16/2022] Open
Abstract
Selenoproteins are proteins that contain selenium within selenocysteine residues. To date, twenty-five mammalian selenoproteins have been identified; however, the functions of nearly half of these selenoproteins are unknown. Although alterations in selenoprotein expression and function have been suggested to play a role in cancer development and progression, few detailed studies have been carried out in this field. Network analyses and data mining of publicly available datasets on gene expression levels in different cancers, and the correlations with patient outcome, represent important tools to study the correlation between selenoproteins and other proteins present in the human interactome, and to determine whether altered selenoprotein expression is cancer type-specific, and/or correlated with cancer patient prognosis. Therefore, in the present study, we used bioinformatics approaches to (i) build up the network of interactions between twenty-five selenoproteins and identify the most inter-correlated proteins/genes, which are named HUB nodes; and (ii) analyze the correlation between selenoprotein gene expression and patient outcome in ten solid tumors. Then, considering the need to confirm by experimental approaches the correlations suggested by the bioinformatics analyses, we decided to evaluate the gene expression levels of the twenty-five selenoproteins and six HUB nodes in androgen receptor-positive (22RV1 and LNCaP) and androgen receptor-negative (DU145 and PC3) cell lines, compared to human nontransformed, and differentiated, prostate epithelial cells (EPN) by RT-qPCR analysis. This analysis confirmed that the combined evaluation of some selenoproteins and HUB nodes could have prognostic value and may improve patient outcome predictions.
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15
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Qazi IH, Yang H, Wei S, Angel C, Pan B, Zhou G, Han H. Dietary selenium deficiency and supplementation differentially modulate the expression of two ER-resident selenoproteins (selenoprotein K and selenoprotein M) in the ovaries of aged mice: Preliminary data. Reprod Biol 2020; 20:441-446. [PMID: 32736983 DOI: 10.1016/j.repbio.2020.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 07/06/2020] [Accepted: 07/11/2020] [Indexed: 02/06/2023]
Abstract
In the present report, we determined the impact of dietary selenium (Se) deficiency and supplementation on the expression of two ER-resident selenoproteins i.e., Selenok and Selenom in the ovaries of aging mice. The mRNA expression of Selenok and Selenom (RT-qPCR) was significantly higher in the ovaries of mice fed diets supplemented with inorganic (ISe-S: 0.33 mg Se/kg) and organic (OSe-S: 0.33 mg Se/kg) Se compared to those fed a Se-deficient (Se-D: 0.08 mg Se/kg) diet and both Se-adequate (ISe-A: 0.15 mg Se/kg and OSe-A: 0.15 mg Se/kg) diets. Similarly, the protein signals of SELENOK (immunofluorescence assay) were also significantly higher in the Se-supplemented groups compared to those fed Se-D and Se-adequate (ISe-A and OSe-A) diets. Meanwhile, the rate of in vitro-produced blastocysts developing from MII oocytes was also evaluated and it was revealed that this rate was significantly higher in the Se-supplemented mice compared to those fed a Se-D diet. Altogether, the dietary Se supplementation increased the expression of Selenok (also its protein expression) and Selenom in the ovaries of aging mice, potentially contributing to an improved developmental potential of in vitro-matured M II oocytes.
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Affiliation(s)
- Izhar Hyder Qazi
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China; Department of Veterinary Anatomy & Histology, Shaheed Benazir Bhutto University of Veterinary and Animal Sciences, Sakrand, 67210, Sindh, Pakistan
| | - Haoxuan Yang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Shao Wei
- Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Christiana Angel
- Department of Veterinary Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China; Department of Veterinary Parasitology, Faculty of Veterinary Sciences, Shaheed Benazir Bhutto University of Veterinary and Animal Sciences, Sakrand, 67210, Sindh, Pakistan
| | - Bo Pan
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Guangbin Zhou
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
| | - Hongbing Han
- Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.
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16
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Liu J, Ekanayake O, Santoleri D, Walker K, Rozovsky S. Efficient Generation of Hydrazides in Proteins by RadA Split Intein. Chembiochem 2020; 21:346-352. [PMID: 31265209 DOI: 10.1002/cbic.201900160] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/30/2019] [Indexed: 12/27/2022]
Abstract
Protein C-terminal hydrazides are useful for bioconjugation and construction of proteins from multiple fragments through native chemical ligation. To generate C-terminal hydrazides in proteins, an efficient intein-based preparation method has been developed by using thiols and hydrazine to accelerate the formation of the transient thioester intermediate and subsequent hydrazinolysis. This approach not only increases the yield, but also improves biocompatibility. The scope of the method has been expanded by employing Pyrococcus horikoshii RadA split intein, which can accommodate a broad range of extein residues before the site of cleavage. The use of split RadA minimizes premature intein N cleavage in vivo and offers control over the initiation of the intein N cleavage reaction. It is expected that this versatile preparation method will expand the utilization of protein C-terminal hydrazides in protein preparation and modification.
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Affiliation(s)
- Jun Liu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA.,Department of Pharmaceutical Chemistry, University of California San Francisco, 555 Mission Bay Boulevard South, San Francisco, CA, 94158, USA
| | - Oshini Ekanayake
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Dominic Santoleri
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA.,Department of Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Kelsi Walker
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
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17
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Marciel MP, Hoffmann PR. Molecular Mechanisms by Which Selenoprotein K Regulates Immunity and Cancer. Biol Trace Elem Res 2019; 192:60-68. [PMID: 31187393 PMCID: PMC6801056 DOI: 10.1007/s12011-019-01774-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/05/2019] [Indexed: 02/07/2023]
Abstract
Many of the 25 members of the selenoprotein family function as enzymes that utilize their selenocysteine (Sec) residues to catalyze redox-based reactions. However, some selenoproteins likely do not exert enzymatic activity by themselves and selenoprotein K (SELENOK) is one such selenoprotein family member that uses its Sec residue in an alternative manner. SELENOK is an endoplasmic reticulum (ER) transmembrane protein that has been shown to be important for ER stress and for calcium-dependent signaling. Molecular mechanisms for the latter have recently been elucidated using knockout mice and genetically manipulated cell lines. These studies have shown that SELENOK interacts with an enzyme in the ER membrane, DHHC6 (letters represent the amino acids aspartic acid, histidine, histidine, and cysteine in the catalytic domain), and the SELENOK/DHHC6 complex catalyzes the transfer of acyl groups such as palmitate to cysteine residues in target proteins, i.e., palmitoylation. One protein palmitoylated by SELENOK/DHHC6 is the calcium channel protein, the inositol 1,4,5-trisphosphate receptor (IP3R), which is acylated as a means for stabilizing the tetrameric calcium channel in the ER membrane. Factors that lower SELENOK levels or function impair IP3R-driven calcium flux. This role for SELENOK is important for the activation and proliferation of immune cells, and recently, a critical role for SELENOK in promoting calcium flux for the progression of melanoma has been demonstrated. This review provides a summary of these findings and their implications in terms of designing new therapeutic interventions that target SELENOK for treating cancers like melanoma.
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Affiliation(s)
- Michael P Marciel
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Peter R Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA.
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18
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Rocca C, Pasqua T, Boukhzar L, Anouar Y, Angelone T. Progress in the emerging role of selenoproteins in cardiovascular disease: focus on endoplasmic reticulum-resident selenoproteins. Cell Mol Life Sci 2019; 76:3969-3985. [PMID: 31218451 PMCID: PMC11105271 DOI: 10.1007/s00018-019-03195-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/29/2019] [Accepted: 06/14/2019] [Indexed: 12/30/2022]
Abstract
Cardiovascular diseases represent one of the most important health problems of developed countries. One of the main actors involved in the onset and development of cardiovascular diseases is the increased production of reactive oxygen species that, through lipid peroxidation, protein oxidation and DNA damage, induce oxidative stress and cell death. Basic and clinical research are ongoing to better understand the endogenous antioxidant mechanisms that counteract oxidative stress, which may allow to identify a possible therapeutic targeting/application in the field of stress-dependent cardiovascular pathologies. In this context, increasing attention is paid to the glutathione/glutathione-peroxidase and to the thioredoxin/thioredoxin-reductase systems, among the most potent endogenous antioxidative systems. These key enzymes, belonging to the selenoprotein family, have a well-established function in the regulation of the oxidative cell balance. The aim of the present review was to highlight the role of selenoproteins in cardiovascular diseases, introducing the emerging cardioprotective role of endoplasmic reticulum-resident members and in particular one of them, namely selenoprotein T or SELENOT. Accumulating evidence indicates that the dysfunction of different selenoproteins is involved in the susceptibility to oxidative stress and its associated cardiovascular alterations, such as congestive heart failure, coronary diseases, impaired cardiac structure and function. Some of them are under investigation as useful pathological biomarkers. In addition, SELENOT exhibited intriguing cardioprotective effects by reducing the cardiac ischemic damage, in terms of infarct size and performance. In conclusion, selenoproteins could represent valuable targets to treat and diagnose cardiovascular diseases secondary to oxidative stress, opening a new avenue in the field of related therapeutic strategies.
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Affiliation(s)
- Carmine Rocca
- Laboratory of Cellular and Molecular Cardiovascular Patho-physiology, Department of Biology, E. and E.S., University of Calabria, Rende, Italy.
- UNIROUEN, Inserm U1239, Neuronal and Neuroendocrine Differentiation and Communication Laboratory, Rouen-Normandie University, 76821, Mont-Saint-Aignan, France.
- Institute for Research and Innovation in Biomedicine, 76000, Rouen, France.
| | - Teresa Pasqua
- Laboratory of Cellular and Molecular Cardiovascular Patho-physiology, Department of Biology, E. and E.S., University of Calabria, Rende, Italy
- "Fondazione Umberto Veronesi", Milan, Italy
| | - Loubna Boukhzar
- UNIROUEN, Inserm U1239, Neuronal and Neuroendocrine Differentiation and Communication Laboratory, Rouen-Normandie University, 76821, Mont-Saint-Aignan, France
- Institute for Research and Innovation in Biomedicine, 76000, Rouen, France
| | - Youssef Anouar
- UNIROUEN, Inserm U1239, Neuronal and Neuroendocrine Differentiation and Communication Laboratory, Rouen-Normandie University, 76821, Mont-Saint-Aignan, France
- Institute for Research and Innovation in Biomedicine, 76000, Rouen, France
| | - Tommaso Angelone
- Laboratory of Cellular and Molecular Cardiovascular Patho-physiology, Department of Biology, E. and E.S., University of Calabria, Rende, Italy.
- National Institute of Cardiovascular Research (INRC), Bologna, Italy.
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19
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Fan RF, Cao CY, Chen MH, Shi QX, Xu SW. Gga-let-7f-3p promotes apoptosis in selenium deficiency-induced skeletal muscle by targeting selenoprotein K. Metallomics 2019; 10:941-952. [PMID: 29905752 DOI: 10.1039/c8mt00083b] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Selenoprotein K (SELENOK) is primarily observed in the endoplasmic reticulum, and serves to maintain the normal physiological functions of skeletal muscle. Skeletal muscle development and regeneration are associated with significant changes in the expression of specific microRNAs (miRNAs). Downregulated SELENOK expression is observed in chicken muscles deficient of Se. However, the mechanisms of miRNA regulation of SELENOK expression remain elusive. Here, deep sequencing was used to detect the miRNA profiles of muscle in Se deficient (-Se group) and normal (C group) chickens. A dual-luciferase reporter assay was adopted to verify the relationship between SELENOK and gga-let-7f-3p. In addition, gga-let-7f-3p was either overexpressed or knocked-down in chicken myoblasts. Furthermore, the cells were treated with N-acetyl-l-cysteine (NAC) or hydrogen peroxide (H2O2) in order to probe the factors involved in oxidative stress, endoplasmic reticulum stress (ERS) and apoptosis, respectively. Relative to the C group, there were 132 differentially expressed miRNAs (including 57 upregulated and 75 downregulated) in the muscles of the -Se group. The dual-luciferase reporter assay showed that SELENOK was a primary target of gga-let-7f-3p. It was also observed that the overexpression or knock-down of gga-let-7f-3p significantly influenced the SELENOK expression. Moreover, NAC blocked mimics of ga-let-7f-3p, thus inducing oxidative stress, ERS and apoptosis. Simultaneously, gga-let-7f-3p inhibitors blocked the stimulant effects caused by H2O2 in chicken myoblasts. Furthermore, Se deficiency downregulated the SELENOK protein expression and induced oxidative stress, ERS and apoptosis in chicken muscles. In conclusion, the gga-let-7f-3p-SELENOK pathway played a pivotal role in Se deficiency mediated muscle injuries through the induction of oxidative stress and ERS, ultimately promoting apoptosis.
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Affiliation(s)
- Rui-Feng Fan
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P. R. China.
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20
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Liu J, Cheng R, Rozovsky S. Synthesis and semisynthesis of selenopeptides and selenoproteins. Curr Opin Chem Biol 2018; 46:41-47. [PMID: 29723718 DOI: 10.1016/j.cbpa.2018.04.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/09/2018] [Accepted: 04/16/2018] [Indexed: 11/19/2022]
Abstract
The versatile chemistry of the genetically encoded amino acid selenocysteine (Sec) is employed in Nature to expand the reactivity of enzymes. In addition to, its role in biology, Sec is used in protein engineering to modify folding, stability, and reactivity of proteins, to introduce conjugations and to facilitate reactions. However, due to limitations related to Sec's insertion mechanism in Nature, much of the production of Sec containing peptides and proteins relies on synthesis and semisynthesis. Here, we review recent advances that have enabled the assembly of complicated selenoproteins, including novel uses of protecting groups for solid phase peptide synthesis, rapid selenoester driven chemical ligations and versatile expressed protein ligations.
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Affiliation(s)
- Jun Liu
- University of California, San Francisco, Department of Pharmaceutical Chemistry, 555 Mission Bay Blvd. South, San Francisco, CA 94158, United States.
| | - Rujin Cheng
- University of Delaware, Department of Chemistry and Biochemistry, Newark, DE 19716, United States
| | - Sharon Rozovsky
- University of Delaware, Department of Chemistry and Biochemistry, Newark, DE 19716, United States.
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21
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Rapid and efficient protein synthesis through expansion of the native chemical ligation concept. Nat Rev Chem 2018. [DOI: 10.1038/s41570-018-0122] [Citation(s) in RCA: 176] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Payne NC, Barber DR, Ruggles EL, Hondal RJ. Can dimedone be used to study selenoproteins? An investigation into the reactivity of dimedone toward oxidized forms of selenocysteine. Protein Sci 2018; 28:41-55. [PMID: 29451338 DOI: 10.1002/pro.3390] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 02/12/2018] [Accepted: 02/13/2018] [Indexed: 01/24/2023]
Abstract
Dimedone is a widely used reagent to assess the redox state of cysteine-containing proteins as it will alkylate sulfenic acid residues, but not sulfinic acid residues. While it has been reported that dimedone can label selenenic acid residues in selenoproteins, we investigated the stability, and reversibility of this label in a model peptide system. We also wondered whether dimedone could be used to detect seleninic acid residues. We used benzenesulfinic acid, benzeneseleninic acid, and model selenocysteine-containing peptides to investigate possible reactions with dimedone. These peptides were incubated with H2 O2 in the presence of dimedone and then the reactions were followed by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS). The native peptide, H-PTVTGCUG-OH (corresponding to the native amino acid sequence of the C-terminus of mammalian thioredoxin reductase), could not be alkylated by dimedone, but could be carboxymethylated with iodoacetic acid. However the "mutant peptide," H-PTVTGAUG-OH, could be labeled with dimedone at low concentrations of H2 O2 , but the reaction was reversible by addition of thiol. Due to the reversible nature of this alkylation, we conclude that dimedone is not a good reagent for detecting selenenic acids in selenoproteins. At high concentrations of H2 O2 , selenium was eliminated from the peptide and a dimeric form of dimedone could be detected using LCMS and 1 H NMR. The dimeric dimedone product forms as a result of a seleno-Pummerer reaction with Sec-seleninic acid. Overall our results show that the reaction of dimedone with oxidized cysteine residues is quite different from the same reaction with oxidized selenocysteine residues.
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Affiliation(s)
- N Connor Payne
- Department of Biochemistry, University of Vermont, College of Medicine, Burlington, Vermont, 05405
| | - Drew R Barber
- Department of Biochemistry, University of Vermont, College of Medicine, Burlington, Vermont, 05405
| | - Erik L Ruggles
- Department of Biochemistry, University of Vermont, College of Medicine, Burlington, Vermont, 05405
| | - Robert J Hondal
- Department of Biochemistry, University of Vermont, College of Medicine, Burlington, Vermont, 05405
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23
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Zhang Z, Liu J, Rozovsky S. Preparation of Selenocysteine-Containing Forms of Human SELENOK and SELENOS. Methods Mol Biol 2018; 1661:241-263. [PMID: 28917050 PMCID: PMC6160314 DOI: 10.1007/978-1-4939-7258-6_18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Selenoprotein K (SELENOK) and Selenoprotein S (SELENOS) are the members of the endoplasmic-reticulum-associated degradation (ERAD) complex, which is responsible for translocating misfolded proteins from the endoplasmic reticulum (ER) to the cytosol for degradation. Besides its involvement in the ERAD, SELENOK was shown to bind and stabilize the palmitoyl transferase DHHC6, and thus contributes to palmitoylation. SELENOK and SELENOS reside in the ER membrane by the way of a single transmembrane helix. Both contain an intrinsically disordered region with a selenocysteine (Sec) located one or two residues away from the C-terminus. Here, we describe the preparation of the Sec-containing forms of SELENOS and SELENOK. SELENOK, which contains no native cysteines, was prepared in an E. coli cysteine auxotroph strain by exploiting the codon and the insertion machinery of Cys for the incorporation of Sec. In contrast, the preparation of SELENOS, which contains functionally important cysteine residues, relied on E. coli's native Sec incorporation mechanism.
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Affiliation(s)
- Zhengqi Zhang
- Department of Chemistry and Biochemistry, University of Delaware, 136 Brown Laboratory, Newark, DE, 19716, USA
| | - Jun Liu
- Department of Chemistry and Biochemistry, University of Delaware, 136 Brown Laboratory, Newark, DE, 19716, USA
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware, 136 Brown Laboratory, Newark, DE, 19716, USA.
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24
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Fredericks GJ, Hoffmann FW, Hondal RJ, Rozovsky S, Urschitz J, Hoffmann PR. Selenoprotein K Increases Efficiency of DHHC6 Catalyzed Protein Palmitoylation by Stabilizing the Acyl-DHHC6 Intermediate. Antioxidants (Basel) 2017; 7:antiox7010004. [PMID: 29286308 PMCID: PMC5789314 DOI: 10.3390/antiox7010004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 12/25/2017] [Accepted: 12/27/2017] [Indexed: 12/16/2022] Open
Abstract
Selenoprotein K (SELENOK) is a selenocysteine (Sec)-containing protein localized in the endoplasmic reticulum (ER) membrane where it interacts with the DHHC6 (where single letter symbols represent Asp-His-His-Cys amino acids) enzyme to promote protein acyl transferase (PAT) reactions. PAT reactions involve the DHHC enzymatic capture of palmitate via a thioester bond to cysteine (Cys) residues that form an unstable palmitoyl-DHHC intermediate, followed by transfer of palmitate to Cys residues of target proteins. How SELENOK facilitates this reaction has not been determined. Splenocyte microsomal preparations from wild-type mice versus SELENOK knockout mice were used to establish PAT assays and showed decreased PAT activity (~50%) under conditions of SELENOK deficiency. Using recombinant, soluble versions of DHHC6 along with SELENOK containing Sec92, Cys92, or alanine (Ala92), we evaluated the stability of the acyl-DHHC6 intermediate and its capacity to transfer the palmitate residue to Cys residues on target peptides. Versions of SELENOK containing either Ala or Cys residues in place of Sec were equivalently less effective than Sec at stabilizing the acyl-DHHC6 intermediate or promoting PAT activity. These data suggest that Sec92 in SELENOK serves to stabilize the palmitoyl-DHHC6 intermediate by reducing hydrolyzation of the thioester bond until transfer of the palmitoyl group to the Cys residue on the target protein can occur.
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Affiliation(s)
- Gregory J Fredericks
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Honolulu, HI 96813, USA.
| | - FuKun W Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Honolulu, HI 96813, USA.
| | - Robert J Hondal
- Department of Biochemistry, University of Vermont, 89 Beaumont Ave, Given Building Room B413, Burlington, VT 05405, USA.
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware, 136 Brown Laboratory, Newark, DE 19716, USA.
| | - Johann Urschitz
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Honolulu, HI 96813, USA.
| | - Peter R Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Honolulu, HI 96813, USA.
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25
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Wolfe AJ, Si W, Zhang Z, Blanden AR, Hsueh YC, Gugel JF, Pham B, Chen M, Loh SN, Rozovsky S, Aksimentiev A, Movileanu L. Quantification of Membrane Protein-Detergent Complex Interactions. J Phys Chem B 2017; 121:10228-10241. [PMID: 29035562 DOI: 10.1021/acs.jpcb.7b08045] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although fundamentally significant in structural, chemical, and membrane biology, the interfacial protein-detergent complex (PDC) interactions have been modestly examined because of the complicated behavior of both detergents and membrane proteins in aqueous phase. Membrane proteins are prone to unproductive aggregation resulting from poor detergent solvation, but the participating forces in this phenomenon remain ambiguous. Here, we show that using rational membrane protein design, targeted chemical modification, and steady-state fluorescence polarization spectroscopy, the detergent desolvation of membrane proteins can be quantitatively evaluated. We demonstrate that depleting the detergent in the sample well produced a two-state transition of membrane proteins between a fully detergent-solvated state and a detergent-desolvated state, the nature of which depended on the interfacial PDC interactions. Using a panel of six membrane proteins of varying hydrophobic topography, structural fingerprint, and charge distribution on the solvent-accessible surface, we provide direct experimental evidence for the contributions of the electrostatic and hydrophobic interactions to the protein solvation properties. Moreover, all-atom molecular dynamics simulations report the major contribution of the hydrophobic forces exerted at the PDC interface. This semiquantitative approach might be extended in the future to include studies of the interfacial PDC interactions of other challenging membrane protein systems of unknown structure. This would have practical importance in protein extraction, solubilization, stabilization, and crystallization.
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Affiliation(s)
- Aaron J Wolfe
- Department of Physics, Syracuse University , 201 Physics Building, Syracuse, New York 13244-1130, United States.,Structural Biology, Biochemistry, and Biophysics Program, Syracuse University , 111 College Place, Syracuse, New York 13244-4100, United States
| | - Wei Si
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University , Nanjing 210096, China.,Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Zhengqi Zhang
- Department of Chemistry and Biochemistry, University of Delaware , 136 Brown Laboratory, Newark, Delaware 19716, United States
| | - Adam R Blanden
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University , 4249 Weiskotten Hall, 766 Irving Av., Syracuse, New York 13210, United States
| | - Yi-Ching Hsueh
- Department of Physics, Syracuse University , 201 Physics Building, Syracuse, New York 13244-1130, United States
| | - Jack F Gugel
- Department of Physics, Syracuse University , 201 Physics Building, Syracuse, New York 13244-1130, United States
| | - Bach Pham
- Department of Chemistry, University of Massachusetts , 820 LGRT, 710 North Pleasant Street, Amherst, Massachusetts 01003-9336, United States
| | - Min Chen
- Department of Chemistry, University of Massachusetts , 820 LGRT, 710 North Pleasant Street, Amherst, Massachusetts 01003-9336, United States
| | - Stewart N Loh
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University , 4249 Weiskotten Hall, 766 Irving Av., Syracuse, New York 13210, United States
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware , 136 Brown Laboratory, Newark, Delaware 19716, United States
| | - Aleksei Aksimentiev
- Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Liviu Movileanu
- Department of Physics, Syracuse University , 201 Physics Building, Syracuse, New York 13244-1130, United States.,Structural Biology, Biochemistry, and Biophysics Program, Syracuse University , 111 College Place, Syracuse, New York 13244-4100, United States.,Department of Biomedical and Chemical Engineering, Syracuse University , 329 Link Hall, Syracuse, New York 13244, United States
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26
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Endoplasmic reticulum-resident selenoproteins as regulators of calcium signaling and homeostasis. Cell Calcium 2017; 70:76-86. [PMID: 28506443 DOI: 10.1016/j.ceca.2017.05.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/30/2017] [Indexed: 01/07/2023]
Abstract
The human selenoprotein family contains 25 members that share the common feature of containing the amino acid, selenocysteine (Sec). Seven selenoproteins are localized to the endoplasmic reticulum (ER) and exhibit different structural features contributing to a range of cellular functions. Some of these functions are either directly or indirectly related to calcium (Ca2+) flux or homeostasis. The presence of the unique Sec residue within these proteins allows some to exert oxidoreductase activity, while the function of the Sec in other ER selenoproteins remains unclear. Some functional insight has been achieved by identifying domains within the ER selenoproteins or through the identification of binding partners. For example, selenoproteins K and N (SELENOK AND SELENON) have been characterized through interactions detected with the inositol 1,4,5-triphosphate receptors (IP3Rs) and the SERCA2b pump, respectively. Others have been linked to chaperone functions related to ER stress or Ca2+ homeostasis. This review summarizes the details gathered to date regarding the ER-resident selenoproteins and their effect on Ca2+ regulated pathways and outcomes in cells.
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Mitchell NJ, Sayers J, Kulkarni SS, Clayton D, Goldys AM, Ripoll-Rozada J, Barbosa Pereira PJ, Chan B, Radom L, Payne RJ. Accelerated Protein Synthesis via One-Pot Ligation-Deselenization Chemistry. Chem 2017. [DOI: 10.1016/j.chempr.2017.04.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Karnaukh EA, Walker LM, Lynch KA, Wiita EG, Buzzeo MC. Electrochemical Study of Selenocystine Reactivity and Reduction at Metallic Surfaces. ChemElectroChem 2017. [DOI: 10.1002/celc.201600717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Elizabeth A. Karnaukh
- Department of Chemistry, Barnard College Columbia University 3009 Broadway 10027 New York, NY USA
| | - Lindsey M. Walker
- Department of Chemistry, Barnard College Columbia University 3009 Broadway 10027 New York, NY USA
| | - Kelsey A. Lynch
- Department of Chemistry, Barnard College Columbia University 3009 Broadway 10027 New York, NY USA
| | - Elizabeth G. Wiita
- Department of Chemistry, Barnard College Columbia University 3009 Broadway 10027 New York, NY USA
| | - Marisa C. Buzzeo
- Department of Chemistry, Barnard College Columbia University 3009 Broadway 10027 New York, NY USA
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Polo A, Guariniello S, Colonna G, Ciliberto G, Costantini S. A study on the structural features of SELK, an over-expressed protein in hepatocellular carcinoma, by molecular dynamics simulations in a lipid-water system. MOLECULAR BIOSYSTEMS 2016; 12:3209-22. [PMID: 27524292 DOI: 10.1039/c6mb00469e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Human SELK is a small trans-membrane selenoprotein characterized by a single trans-membrane helix, while the N-terminal region protrudes into the lumen and the long C-terminal domain into the cytoplasm. SELK is over-expressed in some cancers, like hepatocellular carcinoma; however its precise role in cancer development is presently unknown. SELK is involved in promoting the calcium flux, catalyzing palmitoylation reactions and protein degradation in the endoplasmic reticulum (ER). Therefore, this protein should bind many different proteins like p97/VCP in the supramolecular complex involved in the ER degradation pathway. To study the structural features of SELK in the membrane, we have modeled the protein and then subjected it to molecular dynamics simulations in a lipid-water system. The model shows a N-terminal domain with three β-strands and a short helix, a well-defined trans-membrane helix and a C-terminal domain that lacks a persistent secondary structure and contains long disordered regions. The trajectory analysis during the simulation evidences that: (i) the N-terminal region explores a limited conformational space and is stabilized by intra-peptide H-bonds as well with membrane lipids and water, (ii) the trans-membrane helix was found to be quite stable and (iii) the disordered C-terminal region is stabilized by H-bonds with clustered water molecules as well as by rapidly interchanging intra-peptidic H-bonds, with a structural tendency to compact around the four HUB residues found for this domain. Moreover, N-terminal and C-terminal clusters are distributed differently in the conformational space suggesting that their dynamics are coupled complicatedly through the membrane. Further analyses have shown that the N-terminal has a tendency to pivot around the insertion with the TM-helix through the fluctuations of the three β-strands, which, in turn, show features similar to WW-domains. These results will be useful to study the SELK, SELS and VCP complex representing an interesting druggable target for cancer.
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Affiliation(s)
- Andrea Polo
- Servizio di Informatica Medica, Azienda Ospedaliera Universitaria, Seconda Università di Napoli, Napoli, Italy
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Potenza N, Castiello F, Panella M, Colonna G, Ciliberto G, Russo A, Costantini S. Human MiR-544a Modulates SELK Expression in Hepatocarcinoma Cell Lines. PLoS One 2016; 11:e0156908. [PMID: 27275761 PMCID: PMC4898719 DOI: 10.1371/journal.pone.0156908] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/20/2016] [Indexed: 02/07/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is a multi-factorial cancer with a very poor prognosis; therefore, there are several investigations aimed at the comprehension of the molecular mechanisms leading to development and progression of HCC and at the definition of new therapeutic strategies. We have recently evaluated the expression of selenoproteins in HCC cell lines in comparison with normal hepatocytes. Recent results have shown that some of them are down- and others up-regulated, including the selenoprotein K (SELK), whose expression was also induced by sodium selenite treatment on cells. However, so far very few studies have been dedicated to a possible effect of microRNAs on the expression of selenoproteins and their implication in HCC. In this study, the analysis of SELK 3'UTR by bioinformatics tools led to the identification of eight sites potentially targeted by human microRNAs. They were then subjected to a validation test based on luciferase reporter constructs transfected in HCC cell lines. In this functional screening, miR-544a was able to interact with SELK 3'UTR suppressing the reporter activity. Transfection of a miR-544a mimic or inhibitor was then shown to decrease or increase, respectively, the translation of the endogenous SELK mRNA. Intriguingly, miR-544a expression was found to be modulated by selenium treatment, suggesting a possible role in SELK induction by selenium.
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Affiliation(s)
- Nicoletta Potenza
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Caserta, Italia
| | - Filomena Castiello
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Caserta, Italia
| | - Marta Panella
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Caserta, Italia
| | - Giovanni Colonna
- Servizio di Informatica Medica, Azienda Ospedaliera Universitaria, Seconda Università di Napoli, Napoli, Italia
| | - Gennaro Ciliberto
- Direttore Scientifico, Istituto Nazionale Tumori “Fondazione G. Pascale”- IRCCS, Napoli, Italia
| | - Aniello Russo
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Caserta, Italia
| | - Susan Costantini
- CROM, Istituto Nazionale Tumori “Fondazione G. Pascale”—IRCCS, Napoli, Italia
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Polo A, Colonna G, Guariniello S, Ciliberto G, Costantini S. Deducing the functional characteristics of the human selenoprotein SELK from the structural properties of its intrinsically disordered C-terminal domain. MOLECULAR BIOSYSTEMS 2016; 12:758-72. [PMID: 26735936 DOI: 10.1039/c5mb00679a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The intrinsically disordered proteins (IDPs) cannot be described by a single structural representation but, due to their high structural fluctuation, through conformational ensembles. Certainly, molecular dynamics (MD) simulations represent a useful tool to study their different conformations capturing the conformational distribution. Our group is focusing on the structural characterization of proteins belonging to the seleno-proteome due to their involvement in cancer. They present disordered domains central for their biological function, and, in particular, SELK is a single-pass transmembrane protein that resides in the endoplasmic reticulum membrane (ER) with a C-terminal domain exposed to the cytoplasm that is known to interact with different components of the endoplasmic reticulum associated to the protein degradation (ERAD) pathway. This protein is found to be up-expressed in hepatocellular carcinoma and in other cancers. In this work we performed a detailed analysis of the C-terminal domain sequence of SELK and discovered that it is characterized by many prolines, and four negatively and eleven positively charged residues, which are crucial for its biological activity. This region can be considered as a weak polyelectrolyte and, specifically, a polycation, with high disordered propensity and different phosphorylation sites dislocated along the sequence. Then, we modeled its three-dimensional structure by performing MD simulations in water at neutral pH to analyze the structural stability as well as to identify the presence of HUB residues that play a key structural role as evidenced by the residue-residue interaction network analysis. Through this approach, we demonstrate that the C-terminal domain of SELK (i) presents a poor content of regular secondary structure elements, (ii) is dynamically stabilized by a network of intra-molecular H-bonds and H-bonds with water molecules, (iii) is highly fluctuating and, therefore, can be described only through a conformational ensemble, where we evidenced a distribution of equilibrium conformers which continuously inter-change their conformations. Finally to verify the specific role played by the negative charges, we also performed MD simulations at acidic pH. Overall, all the obtained results evidenced that SELK has the dynamic structural features to be defined as a HUB protein able to interact with multiple members. Therefore, considering the possible role that this protein can have in cancer development and progression, it can represent a target for drug design studies.
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Affiliation(s)
- Andrea Polo
- Servizio di Informatica Medica, Azienda Ospedaliera Universitaria, Seconda Università di Napoli, Napoli, Italy
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Abstract
SIGNIFICANCE Selenoproteins employ selenium to supplement the chemistry available through the common 20 amino acids. These powerful enzymes are affiliated with redox biology, often in connection with the detection, management, and signaling of oxidative stress. Among them, membrane-bound selenoproteins play prominent roles in signaling pathways, Ca(2+) regulation, membrane complexes integrity, and biosynthesis of lipophilic molecules. RECENT ADVANCES The number of selenoproteins whose physiological roles, protein partners, expression, evolution, and biosynthesis are characterized is steadily increasing, thus offering a more nuanced view of this specialized family. This review focuses on human membrane selenoproteins, particularly the five least characterized ones: selenoproteins I, K, N, S, and T. CRITICAL ISSUES Membrane-bound selenoproteins are the least understood, as it is challenging to provide the membrane-like environment required for their biochemical and biophysical characterization. Hence, their studies rely mostly on biological rather than structural and biochemical assays. Another aspect that has not received much attention is the particular role that their membrane association plays in their physiological function. FUTURE DIRECTIONS Findings cited in this review show that it is possible to infer the structure and the membrane-binding mode of these lesser-studied selenoproteins and design experiments to examine the role of the rare amino acid selenocysteine.
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Affiliation(s)
- Jun Liu
- Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware
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Abstract
SIGNIFICANCE Selenoprotein K (SelK) is an endoplasmic reticulum (ER) membrane protein, and its expression is sensitive to dietary selenium levels. A recently described role for SelK as a cofactor in catalyzing protein palmitoylation reactions provides an important link between low dietary selenium intake and suboptimal cellular functions that depend on this selenoprotein for palmitoylation. RECENT ADVANCES A recent breakthrough provided insight into the contribution of SelK to calcium (Ca(2+)) flux in immune cells. In particular, SelK is required for palmitoylation of the Ca(2+) channel protein, inositol-1,4,5-triphosphate receptor (IP3R) in the ER membrane. Without this post-translational modification, expression and function of the IP3R is impaired. SelK is required for palmitoylation of another transmembrane protein, CD36, and very likely other proteins. SelK serves as a cofactor during protein palmitoylation by binding to the protein acyltransferase, DHHC6, thereby facilitating addition of the palmitate via a thioester bond to the sulfhydryl group of cysteine residues of target proteins. CRITICAL ISSUES The association of DHHC6 and SelK is clearly important for immune cell functions and possibly other cell types. The step in the DHHC6 catalyzed S-acylation reaction on which SelK acts remains unclear and possible mechanisms of how the kinetics of the reaction are impacted by SelK binding to DHHC6 are presented here. FUTURE DIRECTIONS Uncovering the specific role of SelK in promoting DHHC6 catalyzed protein palmitoylation may open a new line of inquiry into other selenoproteins playing similar roles as cofactors for different enzymatic processes.
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Affiliation(s)
- Gregory J Fredericks
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii , Honolulu, Hawaii
| | - Peter R Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii , Honolulu, Hawaii
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Delaunay-Moisan A, Appenzeller-Herzog C. The antioxidant machinery of the endoplasmic reticulum: Protection and signaling. Free Radic Biol Med 2015; 83:341-51. [PMID: 25744411 DOI: 10.1016/j.freeradbiomed.2015.02.019] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 02/20/2015] [Accepted: 02/22/2015] [Indexed: 12/16/2022]
Abstract
Cellular metabolism is inherently linked to the production of oxidizing by-products, including reactive oxygen species (ROS) hydrogen peroxide (H2O2). When present in excess, H2O2 can damage cellular biomolecules, but when produced in coordinated fashion, it typically serves as a mobile signaling messenger. It is therefore not surprising that cell health critically relies on both low-molecular-weight and enzymatic antioxidant components, which protect from ROS-mediated damage and shape the propagation and duration of ROS signals. This review focuses on H2O2-antioxidant cross talk in the endoplasmic reticulum (ER), which is intimately linked to the process of oxidative protein folding. ER-resident or ER-regulated sources of H2O2 and other ROS, which are subgrouped into constitutive and stimulated sources, are discussed and set into context with the diverse antioxidant mechanisms in the organelle. These include two types of peroxide-reducing enzymes, a high concentration of glutathione derived from the cytosol, and feedback-regulated thiol-disulfide switches, which negatively control the major ER oxidase ER oxidoreductin-1. Finally, new evidence highlighting emerging principles of H2O2-based cues at the ER will likely set a basis for establishing ER redox processes as a major line of future signaling research. A fundamental problem that remains to be solved is the specific, quantitative, time resolved, and targeted detection of H2O2 in the ER and in specialized ER subdomains.
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Affiliation(s)
- Agnès Delaunay-Moisan
- Laboratoire Stress Oxydants et Cancer, CEA-Saclay, Service de Biologie Intégrative et de Génétique Moléculaire, Institut de Biologie et de Technologie de Saclay, Commissariat à l׳Energie Atomique et aux Energies Alternatives, F-91191 Gif Sur Yvette, France/Institute for Integrative Biology of the Cell (I2BC), Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France.
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Struppe J, Zhang Y, Rozovsky S. (77)Se chemical shift tensor of L-selenocystine: experimental NMR measurements and quantum chemical investigations of structural effects. J Phys Chem B 2015; 119:3643-50. [PMID: 25654666 DOI: 10.1021/jp510857s] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The genetically encoded amino acid selenocysteine and its dimeric form, selenocystine, are both utilized by nature. They are found in active sites of selenoproteins, enzymes that facilitate a diverse range of reactions, including the detoxification of reactive oxygen species and regulation of redox pathways. Due to selenocysteine and selenocystine's specialized biological roles, it is of interest to examine their (77)Se NMR properties and how those can in turn be employed to study biological systems. We report the solid-state (77)Se NMR measurements of the L-selenocystine chemical shift tensor, which provides the first experimental chemical shift tensor information on selenocysteine-containing systems. Quantum chemical calculations of L-selenocystine models were performed to help understand various structural effects on (77)Se L-selenocystine's chemical shift tensor. The effects of protonation state, protein environment, and substituent of selenium-bonded carbon on the isotropic chemical shift were found to be in a range of ca. 10-20 ppm. However, the conformational effect was found to be much larger, spanning ca. 600 ppm for the C-Se-Se-C dihedral angle range of -180° to +180°. Our calculations show that around the minimum energy structure with a C-Se-Se-C dihedral angle of ca. -90°, the energy costs to alter the dihedral angle in the range from -120° to -60° are within only 2.5 kcal/mol. This makes it possible to realize these conformations in a protein or crystal environment. (77)Se NMR was found to be a sensitive probe to such changes and has an isotropic chemical shift range of 272 ± 30 ppm for this energetically favorable conformation range. The energy-minimized structures exhibited calculated isotropic shifts that lay within 3-9% of those reported in previous solution NMR studies. The experimental solid-state NMR isotropic chemical shift is near the lower bound of this calculated range for these readily accessible conformations. These results suggest that the dihedral information may be deduced for a protein with appropriate structural models. These first-time experimental and theoretical results will facilitate future NMR studies of selenium-containing compounds and proteins.
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Affiliation(s)
- Jochem Struppe
- Bruker BioSpin Corporation, 15 Fortune Drive, Manning Park, Billerica, Massachusetts 01821, United States
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