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Heo AJ, Ji CH, Kwon YT. The Cys/N-degron pathway in the ubiquitin-proteasome system and autophagy. Trends Cell Biol 2023; 33:247-259. [PMID: 35945077 DOI: 10.1016/j.tcb.2022.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 10/15/2022]
Abstract
The N-degron pathway is a degradative system in which the N-terminal residues of proteins modulate the half-lives of proteins and other cellular materials. The majority of amino acids in the genetic code have the potential to induce cis or trans degradation in diverse processes, which requires selective recognition between N-degrons and cognate N-recognins. Of particular interest is the Cys/N-degron branch, in which the N-terminal cysteine (Nt-Cys) induces proteolysis via either the ubiquitin (Ub)-proteasome system (UPS) or the autophagy-lysosome pathway (ALP), depending on physiological conditions. Recent studies provided new insights into the central role of Nt-Cys in sensing the fluctuating levels of oxygen and reactive oxygen species (ROS). Here, we discuss the components, regulations, and functions of the Cys/N-degron pathway.
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Affiliation(s)
- Ah Jung Heo
- Cellular Degradation Biology Center and Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul 03080, Korea
| | - Chang Hoon Ji
- Cellular Degradation Biology Center and Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul 03080, Korea; AUTOTAC Bio Inc., Changkyunggung-ro 254, Jongno-gu, Seoul 03077, Korea
| | - Yong Tae Kwon
- Cellular Degradation Biology Center and Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul 03080, Korea; AUTOTAC Bio Inc., Changkyunggung-ro 254, Jongno-gu, Seoul 03077, Korea; Ischemic/Hypoxic Disease Institute, College of Medicine, Seoul National University, Seoul 110-799, Korea.
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2
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Chemical mimetics of the N-degron pathway alleviate systemic inflammation by activating mitophagy and immunometabolic remodeling. Exp Mol Med 2023; 55:333-346. [PMID: 36720915 PMCID: PMC9981610 DOI: 10.1038/s12276-023-00929-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/19/2022] [Accepted: 11/04/2022] [Indexed: 02/02/2023] Open
Abstract
The Arg/N-degron pathway, which is involved in the degradation of proteins bearing an N-terminal signal peptide, is connected to p62/SQSTM1-mediated autophagy. However, the impact of the molecular link between the N-degron and autophagy pathways is largely unknown in the context of systemic inflammation. Here, we show that chemical mimetics of the N-degron Nt-Arg pathway (p62 ligands) decreased mortality in sepsis and inhibited pathological inflammation by activating mitophagy and immunometabolic remodeling. The p62 ligands alleviated systemic inflammation in a mouse model of lipopolysaccharide (LPS)-induced septic shock and in the cecal ligation and puncture model of sepsis. In macrophages, the p62 ligand attenuated the production of proinflammatory cytokines and chemokines in response to various innate immune stimuli. Mechanistically, the p62 ligand augmented LPS-induced mitophagy and inhibited the production of mitochondrial reactive oxygen species in macrophages. The p62 ligand-mediated anti-inflammatory, antioxidative, and mitophagy-activating effects depended on p62. In parallel, the p62 ligand significantly downregulated the LPS-induced upregulation of aerobic glycolysis and lactate production. Together, our findings demonstrate that p62 ligands play a critical role in the regulation of inflammatory responses by orchestrating mitophagy and immunometabolic remodeling.
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Macedo-da-Silva J, Rosa-Fernandes L, Gomes VDM, Santiago VF, Santos DM, Molnar CMS, Barboza BR, de Souza EE, Marques RF, Boscardin SB, Durigon EL, Marinho CRF, Wrenger C, Marie SKN, Palmisano G. Protein Arginylation Is Regulated during SARS-CoV-2 Infection. Viruses 2023; 15:v15020290. [PMID: 36851505 PMCID: PMC9964439 DOI: 10.3390/v15020290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/09/2023] [Accepted: 01/17/2023] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND In 2019, the world witnessed the onset of an unprecedented pandemic. By February 2022, the infection by SARS-CoV-2 has already been responsible for the death of more than 5 million people worldwide. Recently, we and other groups discovered that SARS-CoV-2 infection induces ER stress and activation of the unfolded protein response (UPR) pathway. Degradation of misfolded/unfolded proteins is an essential element of proteostasis and occurs mainly in lysosomes or proteasomes. The N-terminal arginylation of proteins is characterized as an inducer of ubiquitination and proteasomal degradation by the N-degron pathway. RESULTS The role of protein arginylation during SARS-CoV-2 infection was elucidated. Protein arginylation was studied in Vero CCL-81, macrophage-like THP1, and Calu-3 cells infected at different times. A reanalysis of in vivo and in vitro public omics data combined with immunoblotting was performed to measure levels of arginyl-tRNA-protein transferase (ATE1) and its substrates. Dysregulation of the N-degron pathway was specifically identified during coronavirus infections compared to other respiratory viruses. We demonstrated that during SARS-CoV-2 infection, there is an increase in ATE1 expression in Calu-3 and Vero CCL-81 cells. On the other hand, infected macrophages showed no enzyme regulation. ATE1 and protein arginylation was variant-dependent, as shown using P1 and P2 viral variants and HEK 293T cells transfection with the spike protein and receptor-binding domains (RBD). In addition, we report that ATE1 inhibitors, tannic acid and merbromine (MER) reduce viral load. This finding was confirmed in ATE1-silenced cells. CONCLUSIONS We demonstrate that ATE1 is increased during SARS-CoV-2 infection and its inhibition has potential therapeutic value.
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Affiliation(s)
- Janaina Macedo-da-Silva
- GlycoProteomics Laboratory, Department of Parasitology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
| | - Livia Rosa-Fernandes
- GlycoProteomics Laboratory, Department of Parasitology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
- Laboratory of Experimental Immunoparasitology, Department of Parasitology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
| | - Vinicius de Morais Gomes
- GlycoProteomics Laboratory, Department of Parasitology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
| | - Veronica Feijoli Santiago
- GlycoProteomics Laboratory, Department of Parasitology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
| | - Deivid Martins Santos
- GlycoProteomics Laboratory, Department of Parasitology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
| | | | - Bruno Rafael Barboza
- GlycoProteomics Laboratory, Department of Parasitology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
| | - Edmarcia Elisa de Souza
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences at the University of São Paulo, São Paulo 05508-000, Brazil
| | - Rodolfo Ferreira Marques
- Laboratory of Antigen Targeting for Dendritic Cells, Department of Parasitology, Institute of Biomedical Sciences at the University of São Paulo, São Paulo 05508-000, Brazil
| | - Silvia Beatriz Boscardin
- Laboratory of Antigen Targeting for Dendritic Cells, Department of Parasitology, Institute of Biomedical Sciences at the University of São Paulo, São Paulo 05508-000, Brazil
| | - Edison Luiz Durigon
- Laboratory of Clinical and Molecular Virology, Department of Microbiology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
| | - Claudio Romero Farias Marinho
- Laboratory of Experimental Immunoparasitology, Department of Parasitology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
| | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences at the University of São Paulo, São Paulo 05508-000, Brazil
| | - Suely Kazue Nagahashi Marie
- Laboratory of Molecular and Cellular Biology (LIM 15), Department of Neurology, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo 01246-903, Brazil
| | - Giuseppe Palmisano
- GlycoProteomics Laboratory, Department of Parasitology, ICB, University of São Paulo, São Paulo 05508-000, Brazil
- School of Natural Sciences, Macquarie University, Sydney 2109, Australia
- Correspondence: or ; Tel.: +55-11-99920-8662
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Proteostasis Deregulation in Neurodegeneration and Its Link with Stress Granules: Focus on the Scaffold and Ribosomal Protein RACK1. Cells 2022; 11:cells11162590. [PMID: 36010666 PMCID: PMC9406587 DOI: 10.3390/cells11162590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/09/2022] [Accepted: 08/17/2022] [Indexed: 12/12/2022] Open
Abstract
The role of protein misfolding, deposition, and clearance has been the dominant topic in the last decades of investigation in the field of neurodegeneration. The impairment of protein synthesis, along with RNA metabolism and RNA granules, however, are significantly emerging as novel potential targets for the comprehension of the molecular events leading to neuronal deficits. Indeed, defects in ribosome activity, ribosome stalling, and PQC—all ribosome-related processes required for proteostasis regulation—can contribute to triggering stress conditions and promoting the formation of stress granules (SGs) that could evolve in the formation of pathological granules, usually occurring during neurodegenerating effects. In this review, the interplay between proteostasis, mRNA metabolism, and SGs has been explored in a neurodegenerative context with a focus on Alzheimer’s disease (AD), although some defects in these same mechanisms can also be found in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), which are discussed here. Finally, we highlight the role of the receptor for activated C kinase 1 (RACK1) in these pathologies and note that, besides its well characterized function as a scaffold protein, it has an important role in translation and can associate to stress granules (SGs) determining cell fate in response to diverse stress stimuli.
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Kechko OI, Petrushanko IY, Brower CS, Adzhubei AA, Moskalev AA, Piatkov KI, Mitkevich VA, Makarov AA. Beta-amyloid induces apoptosis of neuronal cells by inhibition of the Arg/N-end rule pathway proteolytic activity. Aging (Albany NY) 2019; 11:6134-6152. [PMID: 31446431 PMCID: PMC6738421 DOI: 10.18632/aging.102177] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 08/09/2019] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD) is accompanied by the dysfunction of intracellular protein homeostasis systems, in particular the ubiquitin-proteasome system (UPS). Beta-amyloid peptide (Aβ), which is involved in the processes of neurodegeneration in AD, is a substrate of this system, however its effect on UPS activity is still poorly explored. Here we found that Aβ peptides inhibited the proteolytic activity of the antiapoptotic Arg/N-end rule pathway that is a part of UPS. We identified arginyltransferase Ate1 as a specific component of the Arg/N-end rule pathway targeted by Aβs. Aβ bearing the familial English H6R mutation, known to cause early-onset AD, had an even greater inhibitory effect on protein degradation through the Arg/N-end rule pathway than intact Aβ. This effect was associated with a significant decrease in Ate1-1 and Ate1-3 catalytic activity. We also found that the loss of Ate1 in neuroblastoma Neuro-2a cells eliminated the apoptosis-inducing effects of Aβ peptides. Together, our results show that the apoptotic effect of Aβ peptides is linked to their impairment of Ate1 catalytic activity leading to suppression of the Arg/N-end rule pathway proteolytic activity and ultimately cell death.
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Affiliation(s)
- Olga I Kechko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Irina Yu Petrushanko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | | | - Alexei A Adzhubei
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Alexey A Moskalev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia.,Institute of Biology, Komi Science Center, Russian Academy of Sciences, Syktyvkar 167000, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141701, Russia
| | - Konstantin I Piatkov
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Vladimir A Mitkevich
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Alexander A Makarov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
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6
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Dissmeyer N. Conditional Protein Function via N-Degron Pathway-Mediated Proteostasis in Stress Physiology. ANNUAL REVIEW OF PLANT BIOLOGY 2019; 70:83-117. [PMID: 30892918 DOI: 10.1146/annurev-arplant-050718-095937] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The N-degron pathway, formerly the N-end rule pathway, regulates functions of regulatory proteins. It impacts protein half-life and therefore directs the actual presence of target proteins in the cell. The current concept holds that the N-degron pathway depends on the identity of the amino (N)-terminal amino acid and many other factors, such as the follow-up sequence at the N terminus, conformation, flexibility, and protein localization. It is evolutionarily conserved throughout the kingdoms. One possible entry point for substrates of the N-degron pathway is oxidation of N-terminal Cys residues. Oxidation of N-terminal Cys is decisive for further enzymatic modification of various neo-N termini by arginylation that generates potentially neofunctionalized or instable proteoforms. Here, I focus on the posttranslational modifications that are encompassed by protein degradation via the Cys/Arg branch of the N-degron pathway-part of the PROTEOLYSIS 6 (PRT6)/N-degron pathway-as well as the underlying physiological principles of this branch and its biological significance in stress response.
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Affiliation(s)
- Nico Dissmeyer
- Independent Junior Research Group on Protein Recognition and Degradation, Leibniz Institute of Plant Biochemistry (IPB) and ScienceCampus Halle-Plant-Based Bioeconomy, D-06120 Halle (Saale), Germany; ; Twitter: @NDissmeyer
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7
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Perrar A, Dissmeyer N, Huesgen PF. New beginnings and new ends: methods for large-scale characterization of protein termini and their use in plant biology. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2021-2038. [PMID: 30838411 PMCID: PMC6460961 DOI: 10.1093/jxb/erz104] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/27/2019] [Indexed: 05/17/2023]
Abstract
Dynamic regulation of protein function and abundance plays an important role in virtually every aspect of plant life. Diversifying mechanisms at the RNA and protein level result in many protein molecules with distinct sequence and modification, termed proteoforms, arising from a single gene. Distinct protein termini define proteoforms arising from translation of alternative transcripts, use of alternative translation initiation sites, and different co- and post-translational modifications of the protein termini. Also site-specific proteolytic processing by endo- and exoproteases generates truncated proteoforms, defined by distinct protease-generated neo-N- and neo-C-termini, that may exhibit altered activity, function, and localization compared with their precursor proteins. In eukaryotes, the N-degron pathway targets cytosolic proteins, exposing destabilizing N-terminal amino acids and/or destabilizing N-terminal modifications for proteasomal degradation. This enables rapid and selective removal not only of unfolded proteins, but also of substrate proteoforms generated by proteolytic processing or changes in N-terminal modifications. Here we summarize current protocols enabling proteome-wide analysis of protein termini, which have provided important new insights into N-terminal modifications and protein stability determinants, protein maturation pathways, and protease-substrate relationships in plants.
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Affiliation(s)
- Andreas Perrar
- Forschungszentrum Jülich, Central Institute for Engineering, Electronics and Analytics, ZEA-3 Analytics, Jülich, Germany
| | - Nico Dissmeyer
- Independent Junior Research Group on Protein Recognition and Degradation, Leibniz Institute of Plant Biochemistry (IPB), Weinberg, Halle (Saale), Germany
- ScienceCampus Halle – Plant-based Bioeconomy, Halle (Saale), Germany
| | - Pitter F Huesgen
- Forschungszentrum Jülich, Central Institute for Engineering, Electronics and Analytics, ZEA-3 Analytics, Jülich, Germany
- Medical Faculty and University Hospital, University of Cologne, Cologne, Germany
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8
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Guo L, Ding Z, Huang N, Huang Z, Zhang N, Xia Z. Forkhead Box M1 positively regulates UBE2C and protects glioma cells from autophagic death. Cell Cycle 2017; 16:1705-1718. [PMID: 28767320 PMCID: PMC5602297 DOI: 10.1080/15384101.2017.1356507] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Ubiquitin-conjugating enzyme E2C (UBE2C) is characterized as a crucial molecule in cancer cell growth that plays an essential role in the development of gliomas, but the detailed mechanisms have not been fully elucidated. In this study, we found that Forkhead box transcription factor M1 (FoxM1) overexpression increased UBE2C expression, whereas FoxM1 suppression inhibited UBE2C expression in glioma cells. In addition, high FoxM1/UBE2C expression was significantly correlated with poor prognosis in glioma. We subsequently demonstrated that UBE2C was a direct transcriptional target of FoxM1, and site-directed mutations markedly down-regulated UBE2C promoter activity. Moreover, UBE2C siRNA (si-UBE2C) significantly induced glioma cell autophagy and increased both mCherry-LC3 punctate fluorescence and LC3B-II/LC3-I expression. Notably, the si-UBE2C-induced decrease in cell viability was markedly inhibited by the autophagy inhibitor bafilomycin A1. The silencing of UBE2C resulted in a distinct inhibition of the PI3K-Akt-mTOR pathway, which functions in the negative modulation of autophagy. Collectively, our findings provide clinical and molecular evidence that FoxM1 promotes glioma progression by enhancing UBE2C transcription and that the inhibition of UBE2C partially induces autophagic glioma cell death. Thus, targeting the FoxM1-UBE2C axis has therapeutic potential in the treatment of gliomas.
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Affiliation(s)
- Liang Guo
- a Department of Neurosurgery , The First Affiliated Hospital of Sun Yat-sen University , Guangzhou , Guangdong Province , China
| | - Zhiming Ding
- a Department of Neurosurgery , The First Affiliated Hospital of Sun Yat-sen University , Guangzhou , Guangdong Province , China
| | - Nunu Huang
- a Department of Neurosurgery , The First Affiliated Hospital of Sun Yat-sen University , Guangzhou , Guangdong Province , China
| | - Zhengsong Huang
- a Department of Neurosurgery , The First Affiliated Hospital of Sun Yat-sen University , Guangzhou , Guangdong Province , China
| | - Nu Zhang
- a Department of Neurosurgery , The First Affiliated Hospital of Sun Yat-sen University , Guangzhou , Guangdong Province , China
| | - Zhibo Xia
- a Department of Neurosurgery , The First Affiliated Hospital of Sun Yat-sen University , Guangzhou , Guangdong Province , China
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9
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Hwang HY, Cho SM, Kwon HJ. Approaches for discovering novel bioactive small molecules targeting autophagy. Expert Opin Drug Discov 2017; 12:909-923. [PMID: 28758515 DOI: 10.1080/17460441.2017.1349751] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION In recent years, development of novel bioactive small molecules targeting autophagy has been implicated for autophagy-related disease treatment. Screening new small molecules regulating autophagy allows for the discovery of novel autophagy machinery and therapeutic agents. Areas covered: Two major screening methods for novel autophagy modulators are introduced in this review, namely target based screening and phenotype based screening. With increasing attention focused on chemical compound libraries, coupled with the development of new assay systems, this review attempts to provide an efficient strategy to explore autophagy biology and discover small molecules for the treatment of autophagy-related diseases. Expert opinion: Adopting an appropriate autophagy screening strategy is important for developing small molecules capable of treating neurodegenerative diseases and cancers. Phenotype based screening and target based screening were both used for developing effective small molecules. However, each of these methods has many pros and cons. An efficient approach is suggested to screen for novel lead compounds targeting autophagy, which could provide new hits with better efficiency and rapidity.
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Affiliation(s)
- Hui-Yun Hwang
- a Chemical Genomics Global Research Laboratory, Department of Biotechnology, College of Life Science and Biotechnology , Yonsei University , Seoul , Republic of Korea
| | - Sung Min Cho
- a Chemical Genomics Global Research Laboratory, Department of Biotechnology, College of Life Science and Biotechnology , Yonsei University , Seoul , Republic of Korea
| | - Ho Jeong Kwon
- a Chemical Genomics Global Research Laboratory, Department of Biotechnology, College of Life Science and Biotechnology , Yonsei University , Seoul , Republic of Korea
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10
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Domitrovic T, Fausto AK, Silva TDF, Romanel E, Vaslin MFS. Plant arginyltransferases (ATEs). Genet Mol Biol 2017; 40:253-260. [PMID: 28199445 PMCID: PMC5452128 DOI: 10.1590/1678-4685-gmb-2016-0084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/16/2016] [Indexed: 12/03/2022] Open
Abstract
Regulation of protein stability and/or degradation of misfolded and damaged proteins are essential cellular processes. A part of this regulation is mediated by the so-called N-end rule proteolytic pathway, which, in concert with the ubiquitin proteasome system (UPS), drives protein degradation depending on the N-terminal amino acid sequence. One important enzyme involved in this process is arginyl-t-RNA transferase, known as ATE. This enzyme acts post-translationally by introducing an arginine residue at the N-terminus of specific protein targets to signal degradation via the UPS. However, the function of ATEs has only recently begun to be revealed. Nonetheless, the few studies to date investigating ATE activity in plants points to the great importance of the ATE/N-end rule pathway in regulating plant signaling. Plant development, seed germination, leaf morphology and responses to gas signaling in plants are among the processes affected by the ATE/N-end rule pathway. In this review, we present some of the known biological functions of plant ATE proteins, highlighting the need for more in-depth studies on this intriguing pathway.
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Affiliation(s)
- Tatiana Domitrovic
- Laboratório de Virologia Molecular Vegetal, Departamento de Virologia IMPPG, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Anna K Fausto
- Laboratório de Virologia Molecular Vegetal, Departamento de Virologia IMPPG, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Tatiane da F Silva
- Departamento de Biotecnologia, Escola de Engenharia de Lorena, Universidade de São Paulo, Lorena, SP, Brazil
| | - Elisson Romanel
- Departamento de Biotecnologia, Escola de Engenharia de Lorena, Universidade de São Paulo, Lorena, SP, Brazil
| | - Maite F S Vaslin
- Laboratório de Virologia Molecular Vegetal, Departamento de Virologia IMPPG, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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11
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Abstract
Autophagy is a process tightly regulated by various autophagy-related proteins. It is generally classified into non-selective and selective autophagy. Whereas non-selective autophagy is triggered when the cell is under starvation, selective autophagy is involved in eliminating dysfunctional organelles, misfolded and/or ubiquitylated proteins, and intracellular pathogens. These components are recognized by autophagy receptors and delivered to phagophores. Several selective autophagy receptors have been identified and characterized. They usually have some common domains, such as LC3-interacting- region (LIR) motif, a specific cargo interacting (ubiquitin-dependent or ubiquitin-independent) domain. Recently, structural data of these autophagy receptors has been described, which provides an insight of their function in the selective autophagic process. In this review, we summarize the most up-to-date findings about the structure-function of autophagy receptors that regulates selective autophagy.
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Affiliation(s)
- Byeong-Won Kim
- Department of Life Sciences, Korea University, Seoul 02841, Korea
| | - Do Hoon Kwon
- Department of Life Sciences, Korea University, Seoul 02841, Korea
| | - Hyun Kyu Song
- Department of Life Sciences, Korea University, Seoul 02841, Korea
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12
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Krüger M, Kötter S. Titin, a Central Mediator for Hypertrophic Signaling, Exercise-Induced Mechanosignaling and Skeletal Muscle Remodeling. Front Physiol 2016; 7:76. [PMID: 26973541 PMCID: PMC4771757 DOI: 10.3389/fphys.2016.00076] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/15/2016] [Indexed: 01/09/2023] Open
Abstract
Titin is a giant scaffold protein with multiple functions in striated muscle physiology. Due to the elastic I-band domains and the filament-like integration in the half-sarcomere titin is an important factor for sarcomere assembly and serves as an adaptable molecular spring that determines myofilament distensibility. Protein-interactions e.g., with muscle ankyrin repeat proteins or muscle LIM-protein link titin to hypertrophic signaling and via p62 and Muscle Ring Finger proteins to mechanisms that control protein quality control. This review summarizes our current knowledge on titin as a central node for exercise-induced mechanosignaling and remodeling and further highlights the pathophysiological implications.
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Affiliation(s)
- Martina Krüger
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf Düsseldorf, Germany
| | - Sebastian Kötter
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf Düsseldorf, Germany
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13
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Magraoui FE, Reidick C, Meyer HE, Platta HW. Autophagy-Related Deubiquitinating Enzymes Involved in Health and Disease. Cells 2015; 4:596-621. [PMID: 26445063 PMCID: PMC4695848 DOI: 10.3390/cells4040596] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/15/2015] [Accepted: 09/30/2015] [Indexed: 02/06/2023] Open
Abstract
Autophagy is an evolutionarily-conserved process that delivers diverse cytoplasmic components to the lysosomal compartment for either recycling or degradation. This involves the removal of protein aggregates, the turnover of organelles, as well as the elimination of intracellular pathogens. In this situation, when only specific cargoes should be targeted to the lysosome, the potential targets can be selectively marked by the attachment of ubiquitin in order to be recognized by autophagy-receptors. Ubiquitination plays a central role in this process, because it regulates early signaling events during the induction of autophagy and is also used as a degradation-tag on the potential autophagic cargo protein. Here, we review how the ubiquitin-dependent steps of autophagy are balanced or counteracted by deubiquitination events. Moreover, we highlight the functional role of the corresponding deubiquitinating enzymes and discuss how they might be involved in the occurrence of cancer, neurodegenerative diseases or infection with pathogenic bacteria.
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Affiliation(s)
- Fouzi El Magraoui
- Biomedizinische Forschung, Human Brain Proteomics II, Leibniz-Institut für Analytische Wissenschaften - ISAS -e.V. 44139 Dortmund, Germany.
| | - Christina Reidick
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Hemut E Meyer
- Biomedizinische Forschung, Human Brain Proteomics II, Leibniz-Institut für Analytische Wissenschaften - ISAS -e.V. 44139 Dortmund, Germany.
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
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