1
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Seo DY, Kim D, Nguyen KT, Oh J, Lee JS, Hwang CS. N-Terminally arginylated ubiquitin is attached to histone H2A by RING1B E3 ligase in human cells. Biochem Biophys Res Commun 2023; 666:186-194. [PMID: 36932026 DOI: 10.1016/j.bbrc.2023.02.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/09/2023] [Indexed: 02/11/2023]
Abstract
Ubiquitin (Ub) is highly conserved in all eukaryotic organisms and begins at the N-terminus with Met and Gln. Our recent research demonstrates that N-terminally (Nt-) arginylated Ub can be produced in the yeast Saccharomyces cerevisiae. However, the existence of Nt-arginylated Ub in multicellular organisms remains unknown. Here we explore the mechanism for creating Nt-arginylated Ub using human embryonic kidney HEK293 cells that express various Nt-modified Ubs. We found that Gln-starting Q-Ub was converted into Glu-starting E-Ub by NTAQ1 Nt-deamidase and subsequently Nt-arginylated by ATE1 arginyltransferase in HEK293 cells. We also found that the resulting Arg-Glu-starting RE-Ub was mainly deposited on the Lys119 residue of histone H2A. Furthermore, RING1B E3 Ub ligase mediated the attachment of RE-Ub to H2A. These findings reveal a previously unknown type of histone ubiquitylation which greatly increases the combinatorial complexity of histone and ubiquitin codes.
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Affiliation(s)
- Dong-Young Seo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Dasom Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Kha The Nguyen
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Junsoo Oh
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, Chuncheon, Kangwon, 24341, Republic of Korea
| | - Jung-Shin Lee
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, Chuncheon, Kangwon, 24341, Republic of Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Korea University, Seoul, 02841, Republic of Korea.
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2
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Li Y, Zhao Y, Yan X, Ye C, Weirich S, Zhang B, Wang X, Song L, Jiang C, Jeltsch A, Dong C, Mi W. CRL2 ZER1/ZYG11B recognizes small N-terminal residues for degradation. Nat Commun 2022; 13:7636. [PMID: 36496439 PMCID: PMC9741652 DOI: 10.1038/s41467-022-35169-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 11/17/2022] [Indexed: 12/13/2022] Open
Abstract
N-degron pathway plays an important role in the protein quality control and maintenance of cellular protein homeostasis. ZER1 and ZYG11B, the substrate receptors of the Cullin 2-RING E3 ubiquitin ligase (CRL2), recognize N-terminal (Nt) glycine degrons and participate in the Nt-myristoylation quality control through the Gly/N-degron pathway. Here we show that ZER1 and ZYG11B can also recognize small Nt-residues other than glycine. Specifically, ZER1 binds better to Nt-Ser, -Ala, -Thr and -Cys than to -Gly, while ZYG11B prefers Nt-Gly but also has the capacity to recognize Nt-Ser, -Ala and -Cys in vitro. We found that Nt-Ser, -Ala and -Cys undergo Nt-acetylation catalyzed by Nt-acetyltransferase (NAT), thereby shielding them from recognition by ZER1/ZYG11B in cells. Instead, ZER1/ZYG11B readily targets a selection of small Nt-residues lacking Nt-acetylation for degradation in NAT-deficient cells, implicating its role in the Nt-acetylation quality control. Furthermore, we present the crystal structures of ZER1 and ZYG11B bound to various small Nt-residues and uncover the molecular mechanism of non-acetylated substrate recognition by ZER1 and ZYG11B.
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Affiliation(s)
- Yao Li
- grid.265021.20000 0000 9792 1228The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University General Hospital, The Second Hospital of Tianjin Medical University, Department of Biochemistry and Molecular Biology, Tianjin Medical University, Tianjin, 300070 China
| | - Yueling Zhao
- grid.265021.20000 0000 9792 1228The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University General Hospital, Department of Immunology, Tianjin Medical University, Tianjin, 300070 China
| | - Xiaojie Yan
- grid.265021.20000 0000 9792 1228The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University General Hospital, The Second Hospital of Tianjin Medical University, Department of Biochemistry and Molecular Biology, Tianjin Medical University, Tianjin, 300070 China
| | - Chen Ye
- grid.265021.20000 0000 9792 1228The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University General Hospital, Department of Immunology, Tianjin Medical University, Tianjin, 300070 China
| | - Sara Weirich
- grid.5719.a0000 0004 1936 9713Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
| | - Bing Zhang
- grid.265021.20000 0000 9792 1228The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University General Hospital, The Second Hospital of Tianjin Medical University, Department of Biochemistry and Molecular Biology, Tianjin Medical University, Tianjin, 300070 China
| | - Xiaolu Wang
- grid.265021.20000 0000 9792 1228Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070 China
| | - Lili Song
- grid.265021.20000 0000 9792 1228The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University General Hospital, Department of Immunology, Tianjin Medical University, Tianjin, 300070 China
| | - Chenhao Jiang
- grid.265021.20000 0000 9792 1228The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University General Hospital, Department of Immunology, Tianjin Medical University, Tianjin, 300070 China
| | - Albert Jeltsch
- grid.5719.a0000 0004 1936 9713Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
| | - Cheng Dong
- grid.265021.20000 0000 9792 1228The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University General Hospital, The Second Hospital of Tianjin Medical University, Department of Biochemistry and Molecular Biology, Tianjin Medical University, Tianjin, 300070 China
| | - Wenyi Mi
- grid.265021.20000 0000 9792 1228The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University General Hospital, Department of Immunology, Tianjin Medical University, Tianjin, 300070 China
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3
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Nguyen KT, Ju S, Kim SY, Lee CS, Lee C, Hwang CS. N-Terminal Modifications of Ubiquitin via Methionine Excision, Deamination, and Arginylation Expand the Ubiquitin Code. Mol Cells 2022; 45:158-167. [PMID: 35253655 PMCID: PMC8926867 DOI: 10.14348/molcells.2022.2027] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/16/2021] [Accepted: 01/12/2022] [Indexed: 11/27/2022] Open
Abstract
Ubiquitin (Ub) is post-translationally modified by Ub itself or Ub-like proteins, phosphorylation, and acetylation, among others, which elicits a variety of Ub topologies and cellular functions. However, N-terminal (Nt) modifications of Ub remain unknown, except the linear head-to-tail ubiquitylation via Nt-Met. Here, using the yeast Saccharomyces cerevisiae and an Nt-arginylated Ub-specific antibody, we found that the detectable level of Ub undergoes Nt-Met excision, Nt-deamination, and Nt-arginylation. The resulting Nt-arginylated Ub and its conjugated proteins are upregulated in the stationary-growth phase or by oxidative stress. We further proved the existence of Nt-arginylated Ub in vivo and identified Nt-arginylated Ub-protein conjugates using stable isotope labeling by amino acids in cell culture (SILAC)-based tandem mass spectrometry. In silico structural modeling of Nt-arginylated Ub predicted that Nt-Arg flexibly protrudes from the surface of the Ub, thereby most likely providing a docking site for the factors that recognize it. Collectively, these results reveal unprecedented Nt-arginylated Ub and the pathway by which it is produced, which greatly expands the known complexity of the Ub code.
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Affiliation(s)
- Kha The Nguyen
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Shinyeong Ju
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Sang-Yoon Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Chang-Seok Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Cheolju Lee
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
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4
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Sherpa D, Chrustowicz J, Schulman BA. How the ends signal the end: Regulation by E3 ubiquitin ligases recognizing protein termini. Mol Cell 2022; 82:1424-1438. [PMID: 35247307 PMCID: PMC9098119 DOI: 10.1016/j.molcel.2022.02.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/18/2022] [Accepted: 02/01/2022] [Indexed: 12/31/2022]
Abstract
Specificity of eukaryotic protein degradation is determined by E3 ubiquitin ligases and their selective binding to protein motifs, termed "degrons," in substrates for ubiquitin-mediated proteolysis. From the discovery of the first substrate degron and the corresponding E3 to a flurry of recent studies enabled by modern systems and structural methods, it is clear that many regulatory pathways depend on E3s recognizing protein termini. Here, we review the structural basis for recognition of protein termini by E3s and how this recognition underlies biological regulation. Diverse E3s evolved to harness a substrate's N and/or C terminus (and often adjacent residues as well) in a sequence-specific manner. Regulation is achieved through selective activation of E3s and also through generation of degrons at ribosomes or by posttranslational means. Collectively, many E3 interactions with protein N and C termini enable intricate control of protein quality and responses to cellular signals.
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Affiliation(s)
- Dawafuti Sherpa
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Bavaria, Germany
| | - Jakub Chrustowicz
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Bavaria, Germany
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Bavaria, Germany.
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5
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Parks AR, Escalante-Semerena JC. Protein N-terminal acylation: An emerging field in bacterial cell physiology. CURRENT TRENDS IN MICROBIOLOGY 2022; 16:1-18. [PMID: 37009250 PMCID: PMC10062008 DOI: 10.31300/ctmb.16.2022.1-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
N-terminal (Nt)-acylation is the irreversible addition of an acyl moiety to the terminal alpha amino group of a peptide chain. This type of modification alters the nature of the N terminus, which can interfere with the function of the modified protein by disrupting protein interactions, function, localization, degradation, hydrophobicity, or charge. Nt acylation is found in all domains of life and is a highly common occurrence in eukaryotic cells. However, in prokaryotes very few cases of Nt acylation have been reported. It was once thought that Nt acylation of proteins, other than ribosomal proteins, was uncommon in prokaryotes, but recent evidence suggests that this modification may be more common than once realized. In this review, we discuss what is known about prokaryotic Nt acetylation and the acetyltransferases that are responsible, as well as recent advancements in this field and currently used methods to study Nt acetylation.
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Affiliation(s)
- Anastacia R. Parks
- Department of Microbiology, University of Georgia, Athens, GA 30606, USA
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6
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Eldeeb MA, Fahlman RP, Ragheb MA, Esmaili M. Does N‐Terminal Protein Acetylation Lead to Protein Degradation? Bioessays 2019; 41:e1800167. [DOI: 10.1002/bies.201800167] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 08/12/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Mohamed A. Eldeeb
- Department of Chemistry (Biochemistry Division)Faculty of ScienceCairo University Giza 12613 Egypt
- Department of Neurology and NeurosurgeryMontreal Neurological InstituteMcGill University Montreal Quebec H3A 2B4 Canada
| | - Richard P. Fahlman
- Department of BiochemistryUniversity of Alberta Edmonton Alberta T6G 2R3 Canada
| | - Mohamed A. Ragheb
- Department of Chemistry (Biochemistry Division)Faculty of ScienceCairo University Giza 12613 Egypt
| | - Mansoore Esmaili
- Department of BiochemistryUniversity of Alberta Edmonton Alberta T6G 2R3 Canada
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7
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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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8
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Nguyen KT, Kim JM, Park SE, Hwang CS. N-terminal methionine excision of proteins creates tertiary destabilizing N-degrons of the Arg/N-end rule pathway. J Biol Chem 2019; 294:4464-4476. [PMID: 30674553 DOI: 10.1074/jbc.ra118.006913] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/18/2019] [Indexed: 11/06/2022] Open
Abstract
All organisms begin protein synthesis with methionine (Met). The resulting initiator Met of nascent proteins is irreversibly processed by Met aminopeptidases (MetAPs). N-terminal (Nt) Met excision (NME) is an evolutionarily conserved and essential process operating on up to two-thirds of proteins. However, the universal function of NME remains largely unknown. MetAPs have a well-known processing preference for Nt-Met with Ala, Ser, Gly, Thr, Cys, Pro, or Val at position 2, but using CHX-chase assays to assess protein degradation in yeast cells, as well as protein-binding and RT-qPCR assays, we demonstrate here that NME also occurs on nascent proteins bearing Met-Asn or Met-Gln at their N termini. We found that the NME at these termini exposes the tertiary destabilizing Nt residues (Asn or Gln) of the Arg/N-end rule pathway, which degrades proteins according to the composition of their Nt residues. We also identified a yeast DNA repair protein, MQ-Rad16, bearing a Met-Gln N terminus, as well as a human tropomyosin-receptor kinase-fused gene (TFG) protein, MN-TFG, bearing a Met-Asn N terminus as physiological, MetAP-processed Arg/N-end rule substrates. Furthermore, we show that the loss of the components of the Arg/N-end rule pathway substantially suppresses the growth defects of naa20Δ yeast cells lacking the catalytic subunit of NatB Nt acetylase at 37 °C. Collectively, the results of our study reveal that NME is a key upstream step for the creation of the Arg/N-end rule substrates bearing tertiary destabilizing residues in vivo.
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Affiliation(s)
- Kha The Nguyen
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Jeong-Mok Kim
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Sang-Eun Park
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Cheol-Sang Hwang
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea
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9
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Nguyen KT, Mun SH, Lee CS, Hwang CS. Control of protein degradation by N-terminal acetylation and the N-end rule pathway. Exp Mol Med 2018; 50:1-8. [PMID: 30054456 PMCID: PMC6063864 DOI: 10.1038/s12276-018-0097-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 04/11/2018] [Indexed: 11/10/2022] Open
Abstract
Nα-terminal acetylation (Nt-acetylation) occurs very frequently and is found in most proteins in eukaryotes. Despite the pervasiveness and universality of Nt-acetylation, its general functions in terms of physiological outcomes remain largely elusive. However, several recent studies have revealed that Nt-acetylation has a significant impact on protein stability, activity, folding patterns, cellular localization, etc. In addition, Nt-acetylation marks specific proteins for degradation by a branch of the N-end rule pathway, a subset of the ubiquitin-mediated proteolytic system. The N-end rule associates a protein's in vivo half-life with its N-terminal residue or modifications on its N-terminus. This review provides a current understanding of intracellular proteolysis control by Nt-acetylation and the N-end rule pathway.
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Affiliation(s)
- Kha The Nguyen
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Sang-Hyeon Mun
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Chang-Seok Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea.
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10
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Wadas B, Borjigin J, Huang Z, Oh JH, Hwang CS, Varshavsky A. Degradation of Serotonin N-Acetyltransferase, a Circadian Regulator, by the N-end Rule Pathway. J Biol Chem 2016; 291:17178-96. [PMID: 27339900 DOI: 10.1074/jbc.m116.734640] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Indexed: 12/22/2022] Open
Abstract
Serotonin N-acetyltransferase (AANAT) converts serotonin to N-acetylserotonin (NAS), a distinct biological regulator and the immediate precursor of melatonin, a circulating hormone that influences circadian processes, including sleep. N-terminal sequences of AANAT enzymes vary among vertebrates. Mechanisms that regulate the levels of AANAT are incompletely understood. Previous findings were consistent with the possibility that AANAT may be controlled through its degradation by the N-end rule pathway. By expressing the rat and human AANATs and their mutants not only in mammalian cells but also in the yeast Saccharomyces cerevisiae, and by taking advantage of yeast genetics, we show here that two "complementary" forms of rat AANAT are targeted for degradation by two "complementary" branches of the N-end rule pathway. Specifically, the N(α)-terminally acetylated (Nt-acetylated) Ac-AANAT is destroyed through the recognition of its Nt-acetylated N-terminal Met residue by the Ac/N-end rule pathway, whereas the non-Nt-acetylated AANAT is targeted by the Arg/N-end rule pathway, which recognizes the unacetylated N-terminal Met-Leu sequence of rat AANAT. We also show, by constructing lysine-to-arginine mutants of rat AANAT, that its degradation is mediated by polyubiquitylation of its Lys residue(s). Human AANAT, whose N-terminal sequence differs from that of rodent AANATs, is longer-lived than its rat counterpart and appears to be refractory to degradation by the N-end rule pathway. Together, these and related results indicate both a major involvement of the N-end rule pathway in the control of rodent AANATs and substantial differences in the regulation of rodent and human AANATs that stem from differences in their N-terminal sequences.
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Affiliation(s)
- Brandon Wadas
- From the Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Jimo Borjigin
- the Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Zheping Huang
- the Department of Immunology, University of Connecticut School of Medicine, Farmington, Connecticut 06030, and
| | - Jang-Hyun Oh
- From the Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Cheol-Sang Hwang
- the Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 790-784, South Korea
| | - Alexander Varshavsky
- From the Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125,
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11
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Lee KE, Heo JE, Kim JM, Hwang CS. N-Terminal Acetylation-Targeted N-End Rule Proteolytic System: The Ac/N-End Rule Pathway. Mol Cells 2016; 39:169-78. [PMID: 26883906 PMCID: PMC4794598 DOI: 10.14348/molcells.2016.2329] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/11/2016] [Accepted: 01/14/2016] [Indexed: 12/12/2022] Open
Abstract
Although Nα-terminal acetylation (Nt-acetylation) is a pervasive protein modification in eukaryotes, its general functions in a majority of proteins are poorly understood. In 2010, it was discovered that Nt-acetylation creates a specific protein degradation signal that is targeted by a new class of the N-end rule proteolytic system, called the Ac/N-end rule pathway. Here, we review recent advances in our understanding of the mechanism and biological functions of the Ac/N-end rule pathway, and its crosstalk with the Arg/N-end rule pathway (the classical N-end rule pathway).
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Affiliation(s)
- Kang-Eun Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| | - Ji-Eun Heo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| | - Jeong-Mok Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
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12
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Park SE, Kim JM, Seok OH, Cho H, Wadas B, Kim SY, Varshavsky A, Hwang CS. Control of mammalian G protein signaling by N-terminal acetylation and the N-end rule pathway. Science 2015; 347:1249-1252. [PMID: 25766235 PMCID: PMC4748709 DOI: 10.1126/science.aaa3844] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Rgs2, a regulator of G proteins, lowers blood pressure by decreasing signaling through Gαq. Human patients expressing Met-Leu-Rgs2 (ML-Rgs2) or Met-Arg-Rgs2 (MR-Rgs2) are hypertensive relative to people expressing wild-type Met-Gln-Rgs2 (MQ-Rgs2). We found that wild-type MQ-Rgs2 and its mutant, MR-Rgs2, were destroyed by the Ac/N-end rule pathway, which recognizes N(α)-terminally acetylated (Nt-acetylated) proteins. The shortest-lived mutant, ML-Rgs2, was targeted by both the Ac/N-end rule and Arg/N-end rule pathways. The latter pathway recognizes unacetylated N-terminal residues. Thus, the Nt-acetylated Ac-MX-Rgs2 (X = Arg, Gln, Leu) proteins are specific substrates of the mammalian Ac/N-end rule pathway. Furthermore, the Ac/N-degron of Ac-MQ-Rgs2 was conditional, and Teb4, an endoplasmic reticulum (ER) membrane-embedded ubiquitin ligase, was able to regulate G protein signaling by targeting Ac-MX-Rgs2 proteins for degradation through their N(α)-terminal acetyl group.
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Affiliation(s)
- Sang-Eun Park
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Jeong-Mok Kim
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Ok-Hee Seok
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Hanna Cho
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Brandon Wadas
- Division of Biology and Biological Engineering, California Institute
of Technology, Pasadena, CA 91125, USA
| | - Seon-Young Kim
- Medical Genomics Research Center, KRIBB, Daejeon, South Korea
- Department of Functional Genomics, University of Science and
Technology, Daejeon, South Korea
| | - Alexander Varshavsky
- Division of Biology and Biological Engineering, California Institute
of Technology, Pasadena, CA 91125, USA
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and
Technology, Pohang, Gyeongbuk 790-784, South Korea
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Liat1, an arginyltransferase-binding protein whose evolution among primates involved changes in the numbers of its 10-residue repeats. Proc Natl Acad Sci U S A 2014; 111:E4936-45. [PMID: 25369936 DOI: 10.1073/pnas.1419587111] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The arginyltransferase Ate1 is a component of the N-end rule pathway, which recognizes proteins containing N-terminal degradation signals called N-degrons, polyubiquitylates these proteins, and thereby causes their degradation by the proteasome. At least six isoforms of mouse Ate1 are produced through alternative splicing of Ate1 pre-mRNA. We identified a previously uncharacterized mouse protein, termed Liat1 (ligand of Ate1), that interacts with Ate1 but does not appear to be its arginylation substrate. Liat1 has a higher affinity for the isoforms Ate1(1A7A) and Ate1(1B7A). Liat1 stimulated the in vitro N-terminal arginylation of a model substrate by Ate1. All examined vertebrate and some invertebrate genomes encode proteins sequelogous (similar in sequence) to mouse Liat1. Sequelogs of Liat1 share a highly conserved ∼30-residue region that is shown here to be required for the binding of Liat1 to Ate1. We also identified non-Ate1 proteins that interact with Liat1. In contrast to Liat1 genes of nonprimate mammals, Liat1 genes of primates are subtelomeric, a location that tends to confer evolutionary instability on a gene. Remarkably, Liat1 proteins of some primates, from macaques to humans, contain tandem repeats of a 10-residue sequence, whereas Liat1 proteins of other mammals contain a single copy of this motif. Quantities of these repeats are, in general, different in Liat1 of different primates. For example, there are 1, 4, 13, 13, 17, and 17 repeats in the gibbon, gorilla, orangutan, bonobo, neanderthal, and human Liat1, respectively, suggesting that repeat number changes in this previously uncharacterized protein may contribute to evolution of primates.
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Lee KE, Ahn JY, Kim JM, Hwang CS. Synthetic lethal screen of NAA20, a catalytic subunit gene of NatB N-terminal acetylase in Saccharomyces cerevisiae. J Microbiol 2014; 52:842-8. [PMID: 25163837 DOI: 10.1007/s12275-014-3694-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 06/30/2014] [Accepted: 07/24/2014] [Indexed: 01/08/2023]
Abstract
The Saccharomyces cerevisiae NatB N-terminal acetylase contains a catalytic subunit Naa20 and an auxiliary subunit Naa25. To elucidate the cellular functions of the NatB, we utilized the Synthetic Genetic Array to screen for genes that are essential for cell growth in the absence of NAA20. The genome-wide synthetic lethal screen of NAA20 identified genes encoding for serine/threonine protein kinase Vps15, 1,3-beta-glucanosyltransferase Gas5, and a catabolic repression regulator Mig3. The present study suggests that the catalytic activity of the NatB N-terminal aceytase is involved in vacuolar protein sorting and cell wall maintenance.
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Affiliation(s)
- Kang-Eun Lee
- Department of Life Sciences, Pohang University of Science and Technology, Gyeongbuk, 790-784, Republic of Korea
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