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Aksnes H, Ree R, Arnesen T. Co-translational, Post-translational, and Non-catalytic Roles of N-Terminal Acetyltransferases. Mol Cell 2019; 73:1097-1114. [PMID: 30878283 DOI: 10.1016/j.molcel.2019.02.007] [Citation(s) in RCA: 152] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/23/2019] [Accepted: 02/04/2019] [Indexed: 02/07/2023]
Abstract
Recent studies of N-terminal acetylation have identified new N-terminal acetyltransferases (NATs) and expanded the known functions of these enzymes beyond their roles as ribosome-associated co-translational modifiers. For instance, the identification of Golgi- and chloroplast-associated NATs shows that acetylation of N termini also happens post-translationally. In addition, we now appreciate that some NATs are highly specific; for example, a dedicated NAT responsible for post-translational N-terminal acetylation of actin was recently revealed. Other studies have extended NAT function beyond Nt acetylation, including functions as lysine acetyltransferases (KATs) and non-catalytic roles. Finally, emerging studies emphasize the physiological relevance of N-terminal acetylation, including roles in calorie-restriction-induced longevity and pathological α-synuclein aggregation in Parkinson's disease. Combined, the NATs rise as multifunctional proteins, and N-terminal acetylation is gaining recognition as a major cellular regulator.
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Affiliation(s)
- Henriette Aksnes
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway.
| | - Rasmus Ree
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway
| | - Thomas Arnesen
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway; Department of Biological Sciences, University of Bergen, 5020 Bergen, Norway; Department of Surgery, Haukeland University Hospital, 5021 Bergen, Norway.
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52
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Aksnes H, Marie M, Arnesen T, Drazic A. Actin polymerization and cell motility are affected by NAA80-mediated posttranslational N-terminal acetylation of actin. Commun Integr Biol 2018; 11:e1526572. [PMID: 30534344 PMCID: PMC6284563 DOI: 10.1080/19420889.2018.1526572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/01/2018] [Accepted: 09/08/2018] [Indexed: 10/30/2022] Open
Abstract
Actin is the most abundant protein in our cells, and also one of the most studied. Nevertheless, an important modifier of actin, the N-terminal acetyltransferase (NAT) for actin, remained unknown until now. The recent identification of the enzyme that catalyzes actin acetylation, has opened up for functional studies of unacetylated actin using knockout cells. This enzyme, called NAA80 (Nα-acetyltransferase 80) or NatH, belongs to the NAT family of enzymes, which together provides N-terminal acetylation for around 80 % of the human proteome. In many cases, N-terminal acetylation is essential. In the case of actin, the acetyl group that NAA80 attaches to actin plays an important role in actin's polymerization properties as well as in actin's function in cell migration.
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Affiliation(s)
| | - Michael Marie
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Thomas Arnesen
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Department of Biological Sciences, University of Bergen, Bergen, Norway.,Department of Surgery, Haukeland University Hospital, Bergen, Norway
| | - Adrian Drazic
- Department of Biomedicine, University of Bergen, Bergen, Norway
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53
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Arnesen T, Marmorstein R, Dominguez R. Actin's N-terminal acetyltransferase uncovered. Cytoskeleton (Hoboken) 2018; 75:318-322. [PMID: 30084538 DOI: 10.1002/cm.21455] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/16/2018] [Accepted: 05/22/2018] [Indexed: 12/18/2022]
Abstract
Humans express six highly conserved actin isoforms, which differ the most at their N-termini. Actin's N-terminus undergoes co- and post-translational processing unique among eukaryotic proteins. During translation, the initiator methionine of the two cytoplasmic isoforms is N-terminally acetylated (Nt-acetylated) and that of the four muscle isoforms is removed and the exposed cysteine is Nt-acetylated. Then, an unidentified acetylaminopeptidase post-translationally removes the Ac-Met (or Ac-Cys), and all six isoforms are re-acetylated at the N-terminus. Despite the vital importance of actin for cellular processes ranging from cell motility to organelle trafficking and cell division, the mechanism and functional consequences of Nt-acetylation remained unresolved. Two recent studies significantly advance our understanding of actin Nt-acetylation. Drazic et al. (2018, Proc Natl Acad Sci U S A, 115, 4399-4404) identify actin's dedicated N-terminal acetyltransferase (NAA80/NatH), and demonstrate that Nt-acetylation critically impacts actin assembly in vitro and in cells. NAA80 knockout cells display increased filopodia and lamellipodia formation and accelerated cell motility. In vitro, the absence of Nt-acetylation leads to a decrease in the rates of filament depolymerization and elongation, including formin-induced elongation. Goris et al. (2018, Proc Natl Acad Sci U S A, 115, 4405-4410] describe the structure of Drosophila NAA80 in complex with a peptide-CoA bi-substrate analog mimicking the N-terminus of β-actin. The structure reveals the source of NAA80's specificity for actin's negatively-charged N-terminus. Nt-acetylation neutralizes a positive charge, thus enhancing the overall negative charge of actin's unique N-terminus. Actin's N-terminus is exposed in the filament and influences the interactions of many actin-binding proteins. These advances open the way to understanding the many likely consequences and functional roles of actin Nt-acetylation.
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Affiliation(s)
- Thomas Arnesen
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Department of Biological Sciences, University of Bergen, Bergen, Norway.,Department of Surgery, Haukeland University Hospital, Bergen, Norway
| | - Ronen Marmorstein
- Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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54
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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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55
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Ree R, Varland S, Arnesen T. Spotlight on protein N-terminal acetylation. Exp Mol Med 2018; 50:1-13. [PMID: 30054468 PMCID: PMC6063853 DOI: 10.1038/s12276-018-0116-z] [Citation(s) in RCA: 251] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 04/11/2018] [Indexed: 01/11/2023] Open
Abstract
N-terminal acetylation (Nt-acetylation) is a widespread protein modification among eukaryotes and prokaryotes alike. By appending an acetyl group to the N-terminal amino group, the charge, hydrophobicity, and size of the N-terminus is altered in an irreversible manner. This alteration has implications for the lifespan, folding characteristics and binding properties of the acetylated protein. The enzymatic machinery responsible for Nt-acetylation has been largely described, but significant knowledge gaps remain. In this review, we provide an overview of eukaryotic N-terminal acetyltransferases (NATs) and the impact of Nt-acetylation. We also discuss other functions of known NATs and outline methods for studying Nt-acetylation. A chemical modification of protein structure called N-terminal acetylation occurs normally in many circumstances, but is also implicated in diseases including cancers and developmental disorders. It adds an acetyl group, composed of a carbonyl group (C = O) linked to a methyl group (CH3), to the nitrogen atom found at one end of a protein chain. Thomas Arnesen at the University of Bergen in Norway and colleagues review the understanding of this modification and survey the enzymes that carry it out. Acetylation occurs on around 80% of human proteins and affects crucial aspects of their function. These include the stability that determines proteins’ lifetimes inside cells, the three-dimensional structures that proteins fold into, and the interactions between different proteins. Advances in analytical techniques are yielding new insights into the role of N-terminal acetylation in health and disease.
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Affiliation(s)
- Rasmus Ree
- Department of Biological Sciences, University of Bergen, Thormøhlensgate 55, N-5020, Bergen, Norway.,Department of Biomedicine, University of Bergen, Jonas Lies vei 91, N-5020, Bergen, Norway.,Department of Surgery, Haukeland University Hospital, N-5021, Bergen, Norway
| | - Sylvia Varland
- Department of Biological Sciences, University of Bergen, Thormøhlensgate 55, N-5020, Bergen, Norway.,Department of Biomedicine, University of Bergen, Jonas Lies vei 91, N-5020, Bergen, Norway.,Terrence Donnelly Center for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON, M5S 3E1, Canada
| | - Thomas Arnesen
- Department of Biological Sciences, University of Bergen, Thormøhlensgate 55, N-5020, Bergen, Norway. .,Department of Biomedicine, University of Bergen, Jonas Lies vei 91, N-5020, Bergen, Norway. .,Department of Surgery, Haukeland University Hospital, N-5021, Bergen, Norway.
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56
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Varland S, Arnesen T. Investigating the functionality of a ribosome-binding mutant of NAA15 using Saccharomyces cerevisiae. BMC Res Notes 2018; 11:404. [PMID: 29929531 PMCID: PMC6013942 DOI: 10.1186/s13104-018-3513-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/18/2018] [Indexed: 11/29/2022] Open
Abstract
Objective N-terminal acetylation is a common protein modification that occurs preferentially co-translationally as the substrate N-terminus is emerging from the ribosome. The major N-terminal acetyltransferase complex A (NatA) is estimated to N-terminally acetylate more than 40% of the human proteome. To form a functional NatA complex the catalytic subunit NAA10 must bind the auxiliary subunit NAA15, which properly folds NAA10 for correct substrate acetylation as well as anchors the entire complex to the ribosome. Mutations in these two genes are associated with various neurodevelopmental disorders in humans. The aim of this study was to investigate the in vivo functionality of a Schizosaccharomyces pombe NAA15 mutant that is known to prevent NatA from associating with ribosomes, but retains NatA-specific activity in vitro. Results Here, we show that Schizosaccharomyces pombe NatA can functionally replace Saccharomyces cerevisiae NatA. We further demonstrate that the NatA ribosome-binding mutant Naa15 ΔN K6E is unable to rescue the temperature-sensitive growth phenotype of budding yeast lacking NatA. This finding indicates the in vivo importance of the co-translational nature of NatA-mediated N-terminal acetylation.
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Affiliation(s)
- Sylvia Varland
- Department of Biological Sciences, University of Bergen, 5006, Bergen, Norway. .,Department of Biomedicine, University of Bergen, 5009, Bergen, Norway. .,Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.
| | - Thomas Arnesen
- Department of Biological Sciences, University of Bergen, 5006, Bergen, Norway.,Department of Biomedicine, University of Bergen, 5009, Bergen, Norway.,Department of Surgery, Haukeland University Hospital, 5021, Bergen, Norway
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57
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Gottlieb L, Marmorstein R. Structure of Human NatA and Its Regulation by the Huntingtin Interacting Protein HYPK. Structure 2018; 26:925-935.e8. [PMID: 29754825 DOI: 10.1016/j.str.2018.04.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/22/2018] [Accepted: 04/05/2018] [Indexed: 12/31/2022]
Abstract
Co-translational N-terminal protein acetylation regulates many protein functions including degradation, folding, interprotein interactions, and targeting. Human NatA (hNatA), one of six conserved metazoan N-terminal acetyltransferases, contains Naa10 catalytic and Naa15 auxiliary subunits, and associates with the intrinsically disordered Huntingtin yeast two-hybrid protein K (HYPK). We report on the crystal structures of hNatA and hNatA/HYPK, and associated biochemical and enzymatic analyses. We demonstrate that hNatA contains unique features: a stabilizing inositol hexaphosphate (IP6) molecule and a metazoan-specific Naa15 domain that mediates high-affinity HYPK binding. We find that HYPK harbors intrinsic hNatA-specific inhibitory activity through a bipartite structure: a ubiquitin-associated domain that binds a hNaa15 metazoan-specific region and an N-terminal loop-helix region that distorts the hNaa10 active site. We show that HYPK binding blocks hNaa50 targeting to hNatA, likely limiting Naa50 ribosome localization in vivo. These studies provide a model for metazoan NAT activity and HYPK regulation of N-terminal acetylation.
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Affiliation(s)
- Leah Gottlieb
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Ronen Marmorstein
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA.
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58
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Structural determinants and cellular environment define processed actin as the sole substrate of the N-terminal acetyltransferase NAA80. Proc Natl Acad Sci U S A 2018; 115:4405-4410. [PMID: 29581307 PMCID: PMC5924903 DOI: 10.1073/pnas.1719251115] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
N-terminal acetylation performed by N-terminal acetyltransferases (NATs) is a common protein modification in human cells. A unique NAT, NAA80, was recently found to control actin N-terminal acetylation and cytoskeletal dynamics. In this study, we developed potent and specific bisubstrate inhibitors against NAA80 and determined the crystal structure of NAA80 in complex with an inhibitor mimicking the β-actin N terminus, thus revealing molecular determinants for the substrate specificity and selective inhibition of NAA80. A yeast model uncovered how a cellular determinant, the NatB enzyme, acts to restrict the number of in vivo NAA80 substrates relative to the broader intrinsic capacity of NAA80. Our data provide a starting point for further development of inhibitors for the regulation of actin and cytoskeletal functions. N-terminal (Nt) acetylation is a major protein modification catalyzed by N-terminal acetyltransferases (NATs). Methionine acidic N termini, including actin, are cotranslationally Nt acetylated by NatB in all eukaryotes, but animal actins containing acidic N termini, are additionally posttranslationally Nt acetylated by NAA80. Actin Nt acetylation was found to regulate cytoskeletal dynamics and motility, thus making NAA80 a potential target for cell migration regulation. In this work, we developed potent and selective bisubstrate inhibitors for NAA80 and determined the crystal structure of NAA80 in complex with such an inhibitor, revealing that NAA80 adopts a fold similar to other NAT enzymes but with a more open substrate binding region. Furthermore, in contrast to most other NATs, the substrate specificity of NAA80 is mainly derived through interactions between the enzyme and the acidic amino acids at positions 2 and 3 of the actin substrate and not residues 1 and 2. A yeast model revealed that ectopic expression of NAA80 in a strain lacking NatB activity partially restored Nt acetylation of NatB substrates, including yeast actin. Thus, NAA80 holds intrinsic capacity to posttranslationally Nt acetylate NatB-type substrates in vivo. In sum, the presence of a dominant cotranslational NatB in all eukaryotes, the specific posttranslational actin methionine removal in animals, and finally, the unique structural features of NAA80 leave only the processed actins as in vivo substrates of NAA80. Together, this study reveals the molecular and cellular basis of NAA80 Nt acetylation and provides a scaffold for development of inhibitors for the regulation of cytoskeletal properties.
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59
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DTNB-Based Quantification of In Vitro Enzymatic N-Terminal Acetyltransferase Activity. Methods Mol Biol 2018; 1574:9-15. [PMID: 28315240 DOI: 10.1007/978-1-4939-6850-3_2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
We here describe a quick and easy method to quantitatively measure in vitro acetylation activity of not only N-terminal acetyltransferase (NAT) enzymes, but acetyltransferases using acetyl-coenzyme A as an acetyl donor in general.
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60
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Varland S, Myklebust LM, Goksøyr SØ, Glomnes N, Torsvik J, Varhaug JE, Arnesen T. Identification of an alternatively spliced nuclear isoform of human N-terminal acetyltransferase Naa30. Gene 2017; 644:27-37. [PMID: 29247799 DOI: 10.1016/j.gene.2017.12.019] [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] [Received: 08/17/2017] [Revised: 12/08/2017] [Accepted: 12/11/2017] [Indexed: 12/20/2022]
Abstract
N-terminal acetylation is a highly abundant and important protein modification in eukaryotes catalyzed by N-terminal acetyltransferases (NATs). In humans, six different NATs have been identified (NatA-NatF), each composed of individual subunits and acetylating a distinct set of substrates. Along with most NATs, NatC acts co-translationally at the ribosome. The NatC complex consists of the catalytic subunit Naa30 and the auxiliary subunits Naa35 and Naa38, and can potentially Nt-acetylate cytoplasmic proteins when the initiator methionine is followed by a bulky hydrophobic/amphipathic residue at position 2. Here, we have identified a splice variant of human NAA30, which encodes a truncated protein named Naa30288. The splice variant was abundantly present in thyroid cancer tissues and in several different human cancer cell lines. Surprisingly, Naa30288 localized predominantly to the nucleus, as opposed to annotated Naa30 which has a cytoplasmic localization. Full-length Naa30 acetylated a classical NatC substrate peptide in vitro, whereas no significant NAT activity was detected for Naa30288. Due to the nuclear localization, we also examined acetyltransferase activity towards lysine residues. Neither full-length Naa30 nor Naa30288 displayed any lysine acetyltransferase activity. Overexpression of full-length Naa30 increased cell viability via inhibition of apoptosis. In contrast, Naa30288 did not exert an anti-apoptotic effect. In sum, we identified a novel and widely expressed Naa30 isoform with a potential non-catalytic role in the nucleus.
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Affiliation(s)
- Sylvia Varland
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway
| | - Line M Myklebust
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway
| | - Siri Øfsthus Goksøyr
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway
| | - Nina Glomnes
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway; Department of Clinical Science, University of Bergen, Jonas Lies vei 87, 5021 Bergen, Norway
| | - Janniche Torsvik
- Department of Neurology, Haukeland University Hospital, Jonas Lies vei 87, 5021 Bergen, Norway
| | - Jan Erik Varhaug
- Department of Surgery, Haukeland University Hospital, Jonas Lies vei 87, 5021 Bergen, Norway
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway; Department of Surgery, Haukeland University Hospital, Jonas Lies vei 87, 5021 Bergen, Norway.
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61
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Hong H, Cai Y, Zhang S, Ding H, Wang H, Han A. Molecular Basis of Substrate Specific Acetylation by N-Terminal Acetyltransferase NatB. Structure 2017; 25:641-649.e3. [PMID: 28380339 DOI: 10.1016/j.str.2017.03.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 01/24/2017] [Accepted: 03/09/2017] [Indexed: 11/29/2022]
Abstract
The NatB N-terminal acetyltransferase specifically acetylates the N-terminal group of substrate protein peptides starting with Met-Asp/Glu/Asn/Gln. How NatB recognizes and acetylates these substrates remains unknown. Here, we report crystal structures of a NatB holoenzyme from Candida albicans in the presence of its co-factor CoA and substrate peptides. The auxiliary subunit Naa25 of NatB forms a horseshoe-like deck to hold specifically its catalytic subunit Naa20. The first two amino acids Met and Asp of a substrate peptide mediate the major interactions with the active site in the Naa20 subunit. The hydrogen bonds between the substrate Asp and pocket residues of Naa20 are essential to determine the NatB substrate specificity. Moreover, a hydrogen bond between the amino group of the substrate Met and a carbonyl group in the Naa20 active site directly anchors the substrate toward acetyl-CoA. Together, these structures define a unique molecular mechanism of specific N-terminal acetylation acted by NatB.
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Affiliation(s)
- Haiyan Hong
- State Key Laboratory for Cellular Stress Biology, Department of Biomedical Sciences, School of Life Sciences, Xiamen University, Xiang'an, Xiamen 361102, China
| | - Yongfei Cai
- State Key Laboratory for Cellular Stress Biology, Department of Biomedical Sciences, School of Life Sciences, Xiamen University, Xiang'an, Xiamen 361102, China
| | - Shijun Zhang
- State Key Laboratory for Cellular Stress Biology, Department of Biomedical Sciences, School of Life Sciences, Xiamen University, Xiang'an, Xiamen 361102, China
| | - Hongyan Ding
- State Key Laboratory for Cellular Stress Biology, Department of Biomedical Sciences, School of Life Sciences, Xiamen University, Xiang'an, Xiamen 361102, China
| | - Haitao Wang
- Faculty of Health Sciences, University of Macau, Macau, China
| | - Aidong Han
- State Key Laboratory for Cellular Stress Biology, Department of Biomedical Sciences, School of Life Sciences, Xiamen University, Xiang'an, Xiamen 361102, China.
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62
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Magin RS, Deng S, Zhang H, Cooperman B, Marmorstein R. Probing the interaction between NatA and the ribosome for co-translational protein acetylation. PLoS One 2017; 12:e0186278. [PMID: 29016658 PMCID: PMC5634638 DOI: 10.1371/journal.pone.0186278] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/28/2017] [Indexed: 01/02/2023] Open
Abstract
N-terminal acetylation is among the most abundant protein modifications in eukaryotic cells. Over the last decade, significant progress has been made in elucidating the function of N-terminal acetylation for a number of diverse systems, involved in a wide variety of biological processes. The enzymes responsible for the modification are the N-terminal acetyltransferases (NATs). The NATs are a highly conserved group of enzymes in eukaryotes, which are responsible for acetylating over 80% of the soluble proteome in human cells. Importantly, many of these NATs act co-translationally; they interact with the ribosome near the exit tunnel and acetylate the nascent protein chain as it is being translated. While the structures of many of the NATs have been determined, the molecular basis for the interaction with ribosome is not known. Here, using purified ribosomes and NatA, a very well-studied NAT, we show that NatA forms a stable complex with the ribosome in the absence of other stabilizing factors and through two conserved regions; primarily through an N-terminal domain and an internal basic helix. These regions may orient the active site of the NatA to face the peptide emerging from the exit tunnel. This work provides a framework for understanding how NatA and potentially other NATs interact with the ribosome for co-translational protein acetylation and sets the foundation for future studies to decouple N-terminal acetyltransferase activity from ribosome association.
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Affiliation(s)
- Robert S. Magin
- Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Graduate Group in Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sunbin Deng
- Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Haibo Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Barry Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Ronen Marmorstein
- Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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63
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Lee CC, Peng SH, Shen L, Lee CF, Du TH, Kang ML, Xu GL, Upadhyay AK, Cheng X, Yan YT, Zhang Y, Juan LJ. The Role of N-α-acetyltransferase 10 Protein in DNA Methylation and Genomic Imprinting. Mol Cell 2017; 68:89-103.e7. [PMID: 28943313 DOI: 10.1016/j.molcel.2017.08.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 07/13/2017] [Accepted: 08/24/2017] [Indexed: 01/21/2023]
Abstract
Genomic imprinting is an allelic gene expression phenomenon primarily controlled by allele-specific DNA methylation at the imprinting control region (ICR), but the underlying mechanism remains largely unclear. N-α-acetyltransferase 10 protein (Naa10p) catalyzes N-α-acetylation of nascent proteins, and mutation of human Naa10p is linked to severe developmental delays. Here we report that Naa10-null mice display partial embryonic lethality, growth retardation, brain disorders, and maternal effect lethality, phenotypes commonly observed in defective genomic imprinting. Genome-wide analyses further revealed global DNA hypomethylation and enriched dysregulation of imprinted genes in Naa10p-knockout embryos and embryonic stem cells. Mechanistically, Naa10p facilitates binding of DNA methyltransferase 1 (Dnmt1) to DNA substrates, including the ICRs of the imprinted allele during S phase. Moreover, the lethal Ogden syndrome-associated mutation of human Naa10p disrupts its binding to the ICR of H19 and Dnmt1 recruitment. Our study thus links Naa10p mutation-associated Ogden syndrome to defective DNA methylation and genomic imprinting.
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Affiliation(s)
- Chen-Cheng Lee
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Shih-Huan Peng
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC; Institute of Molecular Medicine, National Taiwan University College of Medicine, Taipei 100, Taiwan, ROC
| | - Li Shen
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Chung-Fan Lee
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Ting-Huei Du
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Ming-Lun Kang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Guo-Liang Xu
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Anup K Upadhyay
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yu-Ting Yan
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Yi Zhang
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
| | - Li-Jung Juan
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC.
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64
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Luo Z, Ge M, Chen J, Geng Q, Tian M, Qiao Z, Bai L, Zhang Q, Zhu C, Xiong Y, Wu K, Liu F, Liu Y, Wu J. HRS plays an important role for TLR7 signaling to orchestrate inflammation and innate immunity upon EV71 infection. PLoS Pathog 2017; 13:e1006585. [PMID: 28854257 PMCID: PMC5595348 DOI: 10.1371/journal.ppat.1006585] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 09/12/2017] [Accepted: 08/16/2017] [Indexed: 12/21/2022] Open
Abstract
Enterovirus 71 (EV71) is an RNA virus that causes hand-foot-mouth disease (HFMD), and even fatal encephalitis in children. Although EV71 pathogenesis remains largely obscure, host immune responses may play important roles in the development of diseases. Recognition of pathogens mediated by Toll-like receptors (TLRs) induces host immune and inflammatory responses. Intracellular TLRs must traffic from the endoplasmic reticulum (ER) to the endolysosomal network from where they initiate complete signaling, leading to inflammatory response. This study reveals a novel mechanism underlying the regulation of TLR7 signaling during EV71 infection. Initially, we show that multiple cytokines are differentially expressed during viral infection and demonstrate that EV71 infection induces the production of proinflammatory cytokines through regulating TLR7-mediated p38 MAPK, and NF-κB signaling pathways. Further studies reveal that the expression of the endosome-associated protein hepatocyte growth factor-regulated tyrosine kinase substrate (HRS) is upregulated and highly correlated with the expression of TLR7 in EV71 infected patients, mice, and cultured cells. Virus-induced HRS subsequently enhances TLR7 complex formation in early- and late-endosome by interacting with TLR7 and TAB1. Moreover, HRS is involved in the regulation of the TLR7/NF-κB/p38 MAPK and the TLR7/NF-κB/IRF3 signaling pathways to induce proinflammatory cytokines and interferons, respectively, resulting in the orchestration of inflammatory and immune responses to the EV71 infection. Therefore, this study demonstrates that HRS acts as a key component of TLR7 signaling to orchestrate immune and inflammatory responses during EV71 infection, and provides new insights into the mechanisms underlying the regulation of host inflammation and innate immunity during EV71 infection. Enterovirus 71 (EV71) is a highly infectious positive-stranded RNA virus that causes hand-foot-mouth disease (HFMD). As a major pathogen, EV71 infection leads to host immune responses in the disease severity. Toll-like receptors (TLRs) can recognize pathogens to induce host immunity and inflammation. Most TLRs must traffic from the endoplasmic reticulum (ER) to endolysosomal network before responding to ligands. The hepatocyte growth factor-regulated tyrosine kinase substrate (HRS) regulates ESCRT-0 complex and endosomal sorting of membrane proteins. HRS is required for ubiquitin-dependent TLR9 targeting to the endolysosome, however, the mechanism by which HRS regulates inflammation and immunity mediated by TLR7 is still largely unknown. Here, we reveal that HRS is a key component of TLR7 signaling to orchestrate immunity and inflammation during EV71 infection. EV71 infection induces the expression of HRS, which subsequently enhances the TLR7 complex formation by binding with TLR7 and TAB1. HRS facilitates TLR7/NF-κB/p38 MAPK and TLR7/NF-κB/IRF3 signaling pathways to produce proinflammatory cytokines and interferons, leading to induction of inflammatory and immune responses. Thus, we identify HRS as a key regulator of TLR7 signaling and illustrate a novel mechanism underlying the regulation of host immunity and inflammation during viral infection.
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Affiliation(s)
- Zhen Luo
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Institute of Medical Microbiology, Jinan University, Guangzhou, China
| | - Maolin Ge
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Junbo Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Qibin Geng
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Mingfu Tian
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhi Qiao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Lan Bai
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Qi Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Chengliang Zhu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Ying Xiong
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Kailang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Fang Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail: (JW); (YL); (FL)
| | - Yingle Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Institute of Medical Microbiology, Jinan University, Guangzhou, China
- * E-mail: (JW); (YL); (FL)
| | - Jianguo Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Institute of Medical Microbiology, Jinan University, Guangzhou, China
- * E-mail: (JW); (YL); (FL)
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65
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Identification of the sequence determinants of protein N-terminal acetylation through a decision tree approach. BMC Bioinformatics 2017; 18:289. [PMID: 28578658 PMCID: PMC5457594 DOI: 10.1186/s12859-017-1699-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/18/2017] [Indexed: 11/29/2022] Open
Abstract
Background N-terminal acetylation is one of the most common protein modifications in eukaryotes and occurs co-translationally when the N-terminus of the nascent polypeptide is still attached to the ribosome. This modification has been shown to be involved in a wide range of biological phenomena such as protein half-life regulation, protein-protein and protein-membrane interactions, and protein subcellular localization. Thus, accurately predicting which proteins receive an acetyl group based on their protein sequence is expected to facilitate the functional study of this modification. As the occurrence of N-terminal acetylation strongly depends on the context of protein sequences, attempts to understand the sequence determinants of N-terminal acetylation were conducted initially by simply examining the N-terminal sequences of many acetylated and unacetylated proteins and more recently by machine learning approaches. However, a complete understanding of the sequence determinants of this modification remains to be elucidated. Results We obtained curated N-terminally acetylated and unacetylated sequences from the UniProt database and employed a decision tree algorithm to identify the sequence determinants of N-terminal acetylation for proteins whose initiator methionine (iMet) residues have been removed. The results suggested that the main determinants of N-terminal acetylation are contained within the first five residues following iMet and that the first and second positions are the most important discriminator for the occurrence of this phenomenon. The results also indicated the existence of position-specific preferred and inhibitory residues that determine the occurrence of N-terminal acetylation. The developed predictor software, termed NT-AcPredictor, accurately predicted the N-terminal acetylation, with an overall performance comparable or superior to those of preceding predictors incorporating machine learning algorithms. Conclusion Our machine learning approach based on a decision tree algorithm successfully provided several sequence determinants of N-terminal acetylation for proteins lacking iMet, some of which have not previously been described. Although these sequence determinants remain insufficient to comprehensively predict the occurrence of this modification, indicating that further work on this topic is still required, the developed predictor, NT-AcPredictor, can be used to predict N-terminal acetylation with an accuracy of more than 80%. Electronic supplementary material The online version of this article (doi:10.1186/s12859-017-1699-4) contains supplementary material, which is available to authorized users.
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66
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Starheim KK, Kalvik TV, Bjørkøy G, Arnesen T. Depletion of the human N-terminal acetyltransferase hNaa30 disrupts Golgi integrity and ARFRP1 localization. Biosci Rep 2017; 37:BSR20170066. [PMID: 28356483 PMCID: PMC5408665 DOI: 10.1042/bsr20170066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/16/2017] [Accepted: 03/28/2017] [Indexed: 01/01/2023] Open
Abstract
The organization of the Golgi apparatus (GA) is tightly regulated. Golgi stack scattering is observed in cellular processes such as apoptosis and mitosis, and has also been associated with disruption of cellular lipid metabolism and neurodegenerative diseases. Our studies show that depletion of the human N-α-acetyltransferase 30 (hNaa30) induces fragmentation of the Golgi stack in HeLa and CAL-62 cell lines. The GA associated GTPase ADP ribosylation factor related protein 1 (ARFRP1) was previously shown to require N-terminal acetylation for membrane association and based on its N-terminal sequence, it is likely to be a substrate of hNaa30. ARFRP1 is involved in endosome-to-trans-Golgi network (TGN) traffic. We observed that ARFRP1 shifted from a predominantly cis-Golgi and TGN localization to localizing both Golgi and non-Golgi vesicular structures in hNaa30-depleted cells. However, we did not observe loss of membrane association of ARFRP1. We conclude that hNaa30 depletion induces Golgi scattering and induces aberrant ARFRP1 Golgi localization.
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Affiliation(s)
- Kristian K Starheim
- Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway
- Department of Molecular Medicine and Cancer Research, Center of Molecular Inflammation Research, Norwegian University of Technology and Natural Sciences, N-7006 Trondheim, Norway
| | - Thomas V Kalvik
- Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway
| | - Geir Bjørkøy
- Department of Molecular Medicine and Cancer Research, Center of Molecular Inflammation Research, Norwegian University of Technology and Natural Sciences, N-7006 Trondheim, Norway
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway
- Department of Surgery, Haukeland University Hospital, N-5021 Bergen, Norway
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67
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Aksnes H, Goris M, Strømland Ø, Drazic A, Waheed Q, Reuter N, Arnesen T. Molecular determinants of the N-terminal acetyltransferase Naa60 anchoring to the Golgi membrane. J Biol Chem 2017; 292:6821-6837. [PMID: 28196861 DOI: 10.1074/jbc.m116.770362] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/29/2017] [Indexed: 11/06/2022] Open
Abstract
Nα-Acetyltransferase 60 (Naa60 or NatF) was recently identified as an unconventional N-terminal acetyltransferase (NAT) because it localizes to organelles, in particular the Golgi apparatus, and has a preference for acetylating N termini of the transmembrane proteins. This knowledge challenged the prevailing view of N-terminal acetylation as a co-translational ribosome-associated process and suggested a new mechanistic functioning for the enzymes responsible for this increasingly recognized protein modification. Crystallography studies on Naa60 were unable to resolve the C-terminal tail of Naa60, which is responsible for the organellar localization. Here, we combined modeling, in vitro assays, and cellular localization studies to investigate the secondary structure and membrane interacting capacity of Naa60. The results show that Naa60 is a peripheral membrane protein. Two amphipathic helices within the Naa60 C terminus bind the membrane directly in a parallel position relative to the lipid bilayer via hydrophobic and electrostatic interactions. A peptide corresponding to the C terminus was unstructured in solution and only folded into an α-helical conformation in the presence of liposomes. Computational modeling and cellular mutational analysis revealed the hydrophobic face of two α-helices to be critical for membranous localization. Furthermore, we found a strong and specific binding preference of Naa60 toward membranes containing the phosphatidylinositol PI(4)P, thus possibly explaining the primary residency of Naa60 at the PI(4)P-rich Golgi. In conclusion, we have defined the mode of cytosolic Naa60 anchoring to the Golgi apparatus, most likely occurring post-translationally and specifically facilitating post-translational N-terminal acetylation of many transmembrane proteins.
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Affiliation(s)
- Henriette Aksnes
- From the Department of Molecular Biology, University of Bergen, N-5020 Bergen
| | - Marianne Goris
- From the Department of Molecular Biology, University of Bergen, N-5020 Bergen
| | - Øyvind Strømland
- From the Department of Molecular Biology, University of Bergen, N-5020 Bergen
| | - Adrian Drazic
- From the Department of Molecular Biology, University of Bergen, N-5020 Bergen
| | - Qaiser Waheed
- From the Department of Molecular Biology, University of Bergen, N-5020 Bergen.,the Computational Biology Unit, Department of Informatics, University of Bergen, N-5020 Bergen, and
| | - Nathalie Reuter
- From the Department of Molecular Biology, University of Bergen, N-5020 Bergen.,the Computational Biology Unit, Department of Informatics, University of Bergen, N-5020 Bergen, and
| | - Thomas Arnesen
- From the Department of Molecular Biology, University of Bergen, N-5020 Bergen, .,the Department of Surgery, Haukeland University Hospital, N-5021 Bergen, Norway
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68
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Ribeiro AL, Silva RD, Foyn H, Tiago MN, Rathore OS, Arnesen T, Martinho RG. Naa50/San-dependent N-terminal acetylation of Scc1 is potentially important for sister chromatid cohesion. Sci Rep 2016; 6:39118. [PMID: 27996020 PMCID: PMC5171793 DOI: 10.1038/srep39118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/17/2016] [Indexed: 12/17/2022] Open
Abstract
The gene separation anxiety (san) encodes Naa50/San, a N-terminal acetyltransferase required for chromosome segregation during mitosis. Although highly conserved among higher eukaryotes, the mitotic function of this enzyme is still poorly understood. Naa50/San was originally proposed to be required for centromeric sister chromatid cohesion in Drosophila and human cells, yet, more recently, it was also suggested to be a negative regulator of microtubule polymerization through internal acetylation of beta Tubulin. We used genetic and biochemical approaches to clarify the function of Naa50/San during development. Our work suggests that Naa50/San is required during tissue proliferation for the correct interaction between the cohesin subunits Scc1 and Smc3. Our results also suggest a working model where Naa50/San N-terminally acetylates the nascent Scc1 polypeptide, and that this co-translational modification is subsequently required for the establishment and/or maintenance of sister chromatid cohesion.
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Affiliation(s)
- Ana Luisa Ribeiro
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.,Center for Biomedical Research (CBMR), University of Algarve, 8005-139 Faro, Portugal
| | - Rui D Silva
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.,Center for Biomedical Research (CBMR), University of Algarve, 8005-139 Faro, Portugal
| | - Håvard Foyn
- Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway
| | - Margarida N Tiago
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.,Center for Biomedical Research (CBMR), University of Algarve, 8005-139 Faro, Portugal
| | - Om Singh Rathore
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.,Center for Biomedical Research (CBMR), University of Algarve, 8005-139 Faro, Portugal
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway.,Department of Surgery, Haukeland University Hospital, N-5021 Bergen, Norway
| | - Rui Gonçalo Martinho
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.,Center for Biomedical Research (CBMR), University of Algarve, 8005-139 Faro, Portugal.,Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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69
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Pavlou D, Kirmizis A. Depletion of histone N-terminal-acetyltransferase Naa40 induces p53-independent apoptosis in colorectal cancer cells via the mitochondrial pathway. Apoptosis 2016; 21:298-311. [PMID: 26666750 PMCID: PMC4746217 DOI: 10.1007/s10495-015-1207-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Protein N-terminal acetylation is an abundant post-translational modification in eukaryotes implicated in various fundamental cellular and biochemical processes. This modification is catalysed by evolutionarily conserved N-terminal acetyltransferases (NATs) whose deregulation has been linked to cancer development and thus, are emerging as useful diagnostic and therapeutic targets. Naa40 is a highly selective NAT that acetylates the amino-termini of histones H4 and H2A and acts as a sensor of cell growth in yeast. In the present study, we examine the role of Naa40 in cancer cell survival. We demonstrate that depletion of Naa40 in HCT116 and HT-29 colorectal cancer cells decreases cell survival by enhancing apoptosis, whereas Naa40 reduction in non-cancerous mouse embryonic fibroblasts has no effect on cell viability. Specifically, Naa40 knockdown in colon cancer cells activates the mitochondrial caspase-9-mediated apoptotic cascade. Consistent with this, we show that caspase-9 activation is required for the induced apoptosis because treatment of cells with an irreversible caspase-9 inhibitor impedes apoptosis when Naa40 is depleted. Furthermore, the effect of Naa40-depletion on cell-death is mediated through a p53-independent mechanism since p53-null HCT116 cells still undergo apoptosis upon reduction of the acetyltransferase. Altogether, these findings reveal an anti-apoptotic role for Naa40 and exhibit its potential as a therapeutic target in colorectal cancers.
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Affiliation(s)
- Demetria Pavlou
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Antonis Kirmizis
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.
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70
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Van Damme P, Kalvik TV, Starheim KK, Jonckheere V, Myklebust LM, Menschaert G, Varhaug JE, Gevaert K, Arnesen T. A Role for Human N-alpha Acetyltransferase 30 (Naa30) in Maintaining Mitochondrial Integrity. Mol Cell Proteomics 2016; 15:3361-3372. [PMID: 27694331 DOI: 10.1074/mcp.m116.061010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Indexed: 12/26/2022] Open
Abstract
N-terminal acetylation (Nt-acetylation) by N-terminal acetyltransferases (NATs) is one of the most common protein modifications in eukaryotes. The NatC complex represents one of three major NATs of which the substrate profile remains largely unexplored. Here, we defined the in vivo human NatC Nt-acetylome on a proteome-wide scale by combining knockdown of its catalytic subunit Naa30 with positional proteomics. We identified 46 human NatC substrates, expanding our current knowledge on the substrate repertoire of NatC which now includes proteins harboring Met-Leu, Met-Ile, Met-Phe, Met-Trp, Met-Val, Met-Met, Met-His and Met-Lys N termini. Upon Naa30 depletion the expression levels of several organellar proteins were found reduced, in particular mitochondrial proteins, some of which were found to be NatC substrates. Interestingly, knockdown of Naa30 induced the loss of mitochondrial membrane potential and fragmentation of mitochondria. In conclusion, NatC Nt-acetylates a large variety of proteins and is essential for mitochondrial integrity and function.
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Affiliation(s)
- Petra Van Damme
- From the ‡Medical Biotechnology Center, VIB, B-9000 Ghent, Belgium; .,§Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Thomas V Kalvik
- ¶Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway
| | - Kristian K Starheim
- ¶Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway.,‖Department of Clinical Science, University of Bergen, N-5020 Bergen, Norway.,**Center of Molecular Inflammation Research, Department of Molecular Medicine and Cancer Research, Norwegian University of Technology and Natural Sciences, N-7006 Trondheim, Norway
| | - Veronique Jonckheere
- From the ‡Medical Biotechnology Center, VIB, B-9000 Ghent, Belgium.,§Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Line M Myklebust
- ¶Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway
| | - Gerben Menschaert
- ‡‡Department of Mathematical Modeling, Statistics and Bioinformatics, Ghent University, B-9000 Ghent, Belgium
| | - Jan Erik Varhaug
- ‖Department of Clinical Science, University of Bergen, N-5020 Bergen, Norway.,§§Department of Surgery, Haukeland University Hospital, N-5021 Bergen, Norway
| | - Kris Gevaert
- From the ‡Medical Biotechnology Center, VIB, B-9000 Ghent, Belgium.,§Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Thomas Arnesen
- ¶Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway.,§§Department of Surgery, Haukeland University Hospital, N-5021 Bergen, Norway
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71
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Microscopy-based Saccharomyces cerevisiae complementation model reveals functional conservation and redundancy of N-terminal acetyltransferases. Sci Rep 2016; 6:31627. [PMID: 27555049 PMCID: PMC4995432 DOI: 10.1038/srep31627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 07/10/2016] [Indexed: 01/05/2023] Open
Abstract
N-terminal acetylation is a highly abundant protein modification catalyzed by N-terminal acetyltransferases (NATs) NatA-NatG. The Saccharomyces cerevisiae protein Arl3 depends on interaction with Sys1 for its localization to the Golgi and this targeting strictly requires NatC-mediated N-terminal acetylation of Arl3. We utilized the Arl3 acetylation-dependent localization phenotype as a model system for assessing the functional conservation and in vivo redundancy of several human NATs. The catalytic subunit of human NatC, hNaa30 (Mak3), restored Arl3 localization in the absence of yNaa30, but only in the presence of either yeast or human Naa35 subunit (Mak10). In contrast, hNaa35 was not able to replace its yeast orthologue without the co-expression of hNaa30, suggesting co-evolution of the two NatC subunits. The most recently discovered and organellar human NAT, NatF/Naa60, restored the Golgi localization of Arl3 in the absence of yNaa30. Interestingly, this was also true for hNaa60 lacking its membrane-binding domain whereas hNaa50 did not complement NatC function. This in vivo redundancy reflects NatC and NatF´s overlapping in vitro substrate specificities. The yeast model presented here provides a robust and rapid readout of NatC and NatF activity in vivo, and revealed evolutionary conservation of the NatC complex and redundancy between NatC and NatF.
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72
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Structure and function of human Naa60 (NatF), a Golgi-localized bi-functional acetyltransferase. Sci Rep 2016; 6:31425. [PMID: 27550639 PMCID: PMC4993997 DOI: 10.1038/srep31425] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/20/2016] [Indexed: 11/08/2022] Open
Abstract
N-terminal acetylation (Nt-acetylation), carried out by N-terminal acetyltransferases (NATs), is a conserved and primary modification of nascent peptide chains. Naa60 (also named NatF) is a recently identified NAT found only in multicellular eukaryotes. This protein was shown to locate on the Golgi apparatus and mainly catalyze the Nt-acetylation of transmembrane proteins, and it also harbors lysine Nε-acetyltransferase (KAT) activity to catalyze the acetylation of lysine ε-amine. Here, we report the crystal structures of human Naa60 (hNaa60) in complex with Acetyl-Coenzyme A (Ac-CoA) or Coenzyme A (CoA). The hNaa60 protein contains an amphipathic helix following its GNAT domain that may contribute to Golgi localization of hNaa60, and the β7-β8 hairpin adopted different conformations in the hNaa60(1-242) and hNaa60(1-199) crystal structures. Remarkably, we found that the side-chain of Phe 34 can influence the position of the coenzyme, indicating a new regulatory mechanism involving enzyme, co-factor and substrates interactions. Moreover, structural comparison and biochemical studies indicated that Tyr 97 and His 138 are key residues for catalytic reaction and that a non-conserved β3-β4 long loop participates in the regulation of hNaa60 activity.
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73
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Aksnes H, Drazic A, Marie M, Arnesen T. First Things First: Vital Protein Marks by N-Terminal Acetyltransferases. Trends Biochem Sci 2016; 41:746-760. [PMID: 27498224 DOI: 10.1016/j.tibs.2016.07.005] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 07/01/2016] [Accepted: 07/08/2016] [Indexed: 11/28/2022]
Abstract
N-terminal (Nt) acetylation is known to be a highly abundant co-translational protein modification, but the recent discovery of Golgi- and chloroplast-resident N-terminal acetyltransferases (NATs) revealed that it can also be added post-translationally. Nt-acetylation may act as a degradation signal in a novel branch of the N-end rule pathway, whose functions include the regulation of human blood pressure. Nt-acetylation also modulates protein interactions, targeting, and folding. In plants, Nt-acetylation plays a role in the control of resistance to drought and in regulation of immune responses. Mutations of specific human NATs that decrease their activity can cause either the lethal Ogden syndrome or severe intellectual disability and cardiovascular defects. In sum, recent advances highlight Nt-acetylation as a key factor in many biological pathways.
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Affiliation(s)
- Henriette Aksnes
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Adrian Drazic
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Michaël Marie
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway; Department of Surgery, Haukeland University Hospital, 5021 Bergen, Norway.
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74
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Szilvay AM, Sarria SV, Mannelqvist M, Aasland R, Furnes C. Proteolytic activity assayed by subcellular localization switching of a substrate. Biochem Biophys Rep 2016; 8:23-28. [PMID: 28955937 PMCID: PMC5613695 DOI: 10.1016/j.bbrep.2016.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 06/27/2016] [Accepted: 07/13/2016] [Indexed: 10/24/2022] Open
Abstract
An approach to assay proteolytic activity in vivo by altering the subcellular localization of a labelled substrate was demonstrated. The assay included a protein shuttling between different cellular compartments and a site-specific recombinant protease. The shuttle protein used was the human immunodeficiency virus type 1 (HIV-1) Rev protein tandemly fused to the enhanced green fluorescent protein (EGFP) and the red fluorescent protein (RFP), while the protease was the site-specific protease VP24 from the herpes simplex virus type 1 (HSV-1). The fluorescent proteins in the Rev fusion protein were separated by a cleavage site specific for the VP24 protease. When co-expressed in COS-7 cells proteolysis was observed by fluorescence microscopy as a shift from a predominantly cytoplasmic localization of the fusion protein RevEGFP to a nuclear localization while the RFP part of the fusion protein remained in the cytoplasm. The cleavage of the fusion protein by VP24 was confirmed by Western blot analysis. The activity of VP24, when tagged N-terminally by the Myc-epitope, was found to be comparable to VP24. These results demonstrates that the activity and localization of a recombinantly expressed protease can be assessed by protease-mediated cleavage of fusion proteins containing a specific protease cleavage site.
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Affiliation(s)
- Anne-Marie Szilvay
- Department of Molecular Biology, University of Bergen, HIB, Post-box 7800, N-5020 Bergen, Norway
| | | | - Monica Mannelqvist
- Department of Molecular Biology, University of Bergen, HIB, Post-box 7800, N-5020 Bergen, Norway.,Centre for Cancer Biomarkers CCBIO, Department of Clinical Medicine, University of Bergen, HIB, Post-box 7800, N-5020 Bergen, Norway
| | - Rein Aasland
- Department of Molecular Biology, University of Bergen, HIB, Post-box 7800, N-5020 Bergen, Norway
| | - Clemens Furnes
- Department of Molecular Biology, University of Bergen, HIB, Post-box 7800, N-5020 Bergen, Norway.,Centre for Organelle Research (CORE), University of Stavanger, Norway
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75
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Støve SI, Magin RS, Foyn H, Haug BE, Marmorstein R, Arnesen T. Crystal Structure of the Golgi-Associated Human Nα-Acetyltransferase 60 Reveals the Molecular Determinants for Substrate-Specific Acetylation. Structure 2016; 24:1044-56. [PMID: 27320834 DOI: 10.1016/j.str.2016.04.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/22/2016] [Accepted: 04/26/2016] [Indexed: 01/17/2023]
Abstract
N-Terminal acetylation is a common and important protein modification catalyzed by N-terminal acetyltransferases (NATs). Six human NATs (NatA-NatF) contain one catalytic subunit each, Naa10 to Naa60, respectively. In contrast to the ribosome-associated NatA to NatE, NatF/Naa60 specifically associates with Golgi membranes and acetylates transmembrane proteins. To gain insight into the molecular basis for the function of Naa60, we developed an Naa60 bisubstrate CoA-peptide conjugate inhibitor, determined its X-ray structure when bound to CoA and inhibitor, and carried out biochemical experiments. We show that Naa60 adapts an overall fold similar to that of the catalytic subunits of ribosome-associated NATs, but with the addition of two novel elongated loops that play important roles in substrate-specific binding. One of these loops mediates a dimer to monomer transition upon substrate-specific binding. Naa60 employs a catalytic mechanism most similar to Naa50. Collectively, these data reveal the molecular basis for Naa60-specific acetyltransferase activity with implications for its Golgi-specific functions.
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Affiliation(s)
- Svein Isungset Støve
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway; Department of Surgery, Haukeland University Hospital, 5021 Bergen, Norway
| | - Robert S Magin
- Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Program in Gene Expression and Regulation, Wistar Institute, Philadelphia, PA 19104, USA
| | - Håvard Foyn
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Bengt Erik Haug
- Department of Chemistry, University of Bergen, 5020 Bergen, Norway
| | - Ronen Marmorstein
- Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Program in Gene Expression and Regulation, Wistar Institute, Philadelphia, PA 19104, USA.
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway; Department of Surgery, Haukeland University Hospital, 5021 Bergen, Norway.
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76
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Drazic A, Myklebust LM, Ree R, Arnesen T. The world of protein acetylation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1372-401. [PMID: 27296530 DOI: 10.1016/j.bbapap.2016.06.007] [Citation(s) in RCA: 515] [Impact Index Per Article: 64.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 06/04/2016] [Accepted: 06/08/2016] [Indexed: 12/30/2022]
Abstract
Acetylation is one of the major post-translational protein modifications in the cell, with manifold effects on the protein level as well as on the metabolome level. The acetyl group, donated by the metabolite acetyl-coenzyme A, can be co- or post-translationally attached to either the α-amino group of the N-terminus of proteins or to the ε-amino group of lysine residues. These reactions are catalyzed by various N-terminal and lysine acetyltransferases. In case of lysine acetylation, the reaction is enzymatically reversible via tightly regulated and metabolism-dependent mechanisms. The interplay between acetylation and deacetylation is crucial for many important cellular processes. In recent years, our understanding of protein acetylation has increased significantly by global proteomics analyses and in depth functional studies. This review gives a general overview of protein acetylation and the respective acetyltransferases, and focuses on the regulation of metabolic processes and physiological consequences that come along with protein acetylation.
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Affiliation(s)
- Adrian Drazic
- Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway
| | - Line M Myklebust
- Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway
| | - Rasmus Ree
- Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway; Department of Surgery, Haukeland University Hospital, N-5021 Bergen, Norway
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway; Department of Surgery, Haukeland University Hospital, N-5021 Bergen, Norway.
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77
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Affiliation(s)
- Henriette Aksnes
- Department of Molecular Biology, University of Bergen, Bergen, Norway
| | - Michaël Marie
- Department of Molecular Biology, University of Bergen, Bergen, Norway
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, Bergen, Norway.,Department of Surgery, Haukeland University Hospital, Bergen, Norway
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78
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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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79
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Rathore OS, Faustino A, Prudêncio P, Van Damme P, Cox CJ, Martinho RG. Absence of N-terminal acetyltransferase diversification during evolution of eukaryotic organisms. Sci Rep 2016; 6:21304. [PMID: 26861501 PMCID: PMC4748286 DOI: 10.1038/srep21304] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 01/18/2016] [Indexed: 11/09/2022] Open
Abstract
Protein N-terminal acetylation is an ancient and ubiquitous co-translational modification catalyzed by a highly conserved family of N-terminal acetyltransferases (NATs). Prokaryotes have at least 3 NATs, whereas humans have six distinct but highly conserved NATs, suggesting an increase in regulatory complexity of this modification during eukaryotic evolution. Despite this, and against our initial expectations, we determined that NAT diversification did not occur in the eukaryotes, as all six major human NATs were most likely present in the Last Eukaryotic Common Ancestor (LECA). Furthermore, we also observed that some NATs were actually secondarily lost during evolution of major eukaryotic lineages; therefore, the increased complexity of the higher eukaryotic proteome occurred without a concomitant diversification of NAT complexes.
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Affiliation(s)
- Om Singh Rathore
- Department of Biomedical Sciences and Medicine, Faro, Portugal.,Center for Biomedical Research (CBMR), Faro, Portugal.,ProRegeM-PhD Program in Mechanisms of Disease and Regenerative Medicine, Faro, Portugal
| | - Alexandra Faustino
- Department of Biomedical Sciences and Medicine, Faro, Portugal.,Center for Biomedical Research (CBMR), Faro, Portugal
| | - Pedro Prudêncio
- Department of Biomedical Sciences and Medicine, Faro, Portugal.,Center for Biomedical Research (CBMR), Faro, Portugal.,Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras 2781-901, Portugal
| | - Petra Van Damme
- Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Cymon J Cox
- Center of Marine Sciences, University of Algarve, Faro, Portugal
| | - Rui Gonçalo Martinho
- Department of Biomedical Sciences and Medicine, Faro, Portugal.,Center for Biomedical Research (CBMR), Faro, Portugal.,Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras 2781-901, Portugal
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80
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Aksnes H, Drazic A, Arnesen T. (Hyper)tension release by N-terminal acetylation. Trends Biochem Sci 2015; 40:422-4. [DOI: 10.1016/j.tibs.2015.05.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
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81
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Varland S, Osberg C, Arnesen T. N-terminal modifications of cellular proteins: The enzymes involved, their substrate specificities and biological effects. Proteomics 2015; 15:2385-401. [PMID: 25914051 PMCID: PMC4692089 DOI: 10.1002/pmic.201400619] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 03/04/2015] [Accepted: 04/21/2015] [Indexed: 01/18/2023]
Abstract
The vast majority of eukaryotic proteins are N-terminally modified by one or more processing enzymes. Enzymes acting on the very first amino acid of a polypeptide include different peptidases, transferases, and ligases. Methionine aminopeptidases excise the initiator methionine leaving the nascent polypeptide with a newly exposed amino acid that may be further modified. N-terminal acetyl-, methyl-, myristoyl-, and palmitoyltransferases may attach an acetyl, methyl, myristoyl, or palmitoyl group, respectively, to the α-amino group of the target protein N-terminus. With the action of ubiquitin ligases, one or several ubiquitin molecules are transferred, and hence, constitute the N-terminal modification. Modifications at protein N-termini represent an important contribution to proteomic diversity and complexity, and are essential for protein regulation and cellular signaling. Consequently, dysregulation of the N-terminal modifying enzymes is implicated in human diseases. We here review the different protein N-terminal modifications occurring co- or post-translationally with emphasis on the responsible enzymes and their substrate specificities.
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Affiliation(s)
- Sylvia Varland
- Department of Molecular Biology, University of Bergen, Bergen, Norway
| | - Camilla Osberg
- Department of Molecular Biology, University of Bergen, Bergen, Norway.,Department of Surgery, Haukeland University Hospital, Bergen, Norway
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, Bergen, Norway.,Department of Surgery, Haukeland University Hospital, Bergen, Norway
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82
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Silva RD, Martinho RG. Developmental roles of protein N-terminal acetylation. Proteomics 2015; 15:2402-9. [PMID: 25920796 DOI: 10.1002/pmic.201400631] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 03/26/2015] [Accepted: 04/24/2015] [Indexed: 12/30/2022]
Abstract
Discovered more than 50 years ago, N-terminal acetylation (N-Ac) is one of the most common protein modifications. Catalyzed by different N-terminal acetyltransferases (NATs), N-Ac was originally believed to mostly promote protein stability. However, several functional consequences at substrate level were recently described that yielded important new insights about the distinct molecular functions for this modification. The ubiquitous and apparent irreversible nature of this protein modification leads to the assumption that N-Ac mostly executes constitutive functions. In spite of the large number of substrates for each NAT, recent studies in multicellular organisms have nevertheless indicated very specific phenotypes after NAT loss. This raises the hypothesis that in vivo N-Ac is only functionally rate limiting for a small subset of substrates. In this review, we will discuss the function of N-Ac in the context of a developing organism. We will propose that some rate limiting NAT substrates may be tissue-specific leading to differential functions of N-Ac during development of multicellular organisms. Moreover, we will also propose the existence of tissue and developmental-specific mechanisms that differentially regulate N-Ac.
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Affiliation(s)
- Rui D Silva
- Departamento de Ciências Biomédicas e Medicina, and Center for Biomedical Research, Universidade do Algarve, Campus de Gambelas, Faro, Portugal
| | - Rui G Martinho
- Departamento de Ciências Biomédicas e Medicina, and Center for Biomedical Research, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.,Instituto Gulbenkian de Ciência, Oeiras, Portugal
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83
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Van Damme P, Hole K, Gevaert K, Arnesen T. N-terminal acetylome analysis reveals the specificity of Naa50 (Nat5) and suggests a kinetic competition between N-terminal acetyltransferases and methionine aminopeptidases. Proteomics 2015; 15:2436-46. [PMID: 25886145 DOI: 10.1002/pmic.201400575] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 03/04/2015] [Accepted: 04/14/2015] [Indexed: 11/08/2022]
Abstract
Cotranslational N-terminal (Nt-) acetylation of nascent polypeptides is mediated by N-terminal acetyltransferases (NATs). The very N-terminal amino acid sequence largely determines whether or not a given protein is Nt-acetylated. Currently, there are six distinct NATs characterized, NatA-NatF, in humans of which the in vivo substrate specificity of Naa50 (Nat5)/NatE, an alternative catalytic subunit of the human NatA, so far remained elusive. In this study, we quantitatively compared the Nt-acetylomes of wild-type yeast S. cerevisiae expressing the endogenous yeast Naa50 (yNaa50), the congenic strain lacking yNaa50, and an otherwise identical strain expressing human Naa50 (hNaa50). Six canonical yeast NatA substrates were Nt-acetylated less in yeast lacking yNaa50 than in wild-type yeast. In contrast, the ectopically expressed hNaa50 resulted, predominantly, in the Nt-acetylation of N-terminal Met (iMet) starting N-termini, including iMet-Lys, iMet-Val, iMet-Ala, iMet-Tyr, iMet-Phe, iMet-Leu, iMet-Ser, and iMet-Thr N-termini. This identified hNaa50 as being similar, in its substrate specificity, to the previously characterized hNaa60/NatF. In addition, the identification, in yNaa50-lacking yeast expressing hNaa50, of Nt-acetylated iMet followed by a small residue such as Ser, Thr, Ala, or Val, revealed a kinetic competition between Naa50 and Met-aminopeptidases (MetAPs), and implied that Nt-acetylated iMet followed by a small residue cannot be removed by MetAPs, a deduction supported by our in vitro data. As such, Naa50-mediated Nt-acetylation may act to retain the iMet of proteins of otherwise MetAP susceptible N-termini and the fraction of retained and Nt-acetylated iMet (followed by a small residue) in such a setting would be expected to depend on the relative levels of ribosome-associated Naa50/NatA and MetAPs.
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Affiliation(s)
- Petra Van Damme
- Department of Medical Protein Research, VIB, Ghent, Belgium.,Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Kristine Hole
- Department of Molecular Biology, University of Bergen, Bergen, Norway.,Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Kris Gevaert
- Department of Medical Protein Research, VIB, Ghent, Belgium.,Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, Bergen, Norway.,Department of Surgery, Haukeland University Hospital, Bergen, Norway
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84
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The biological functions of Naa10 - From amino-terminal acetylation to human disease. Gene 2015; 567:103-31. [PMID: 25987439 DOI: 10.1016/j.gene.2015.04.085] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 04/20/2015] [Accepted: 04/27/2015] [Indexed: 01/07/2023]
Abstract
N-terminal acetylation (NTA) is one of the most abundant protein modifications known, and the N-terminal acetyltransferase (NAT) machinery is conserved throughout all Eukarya. Over the past 50 years, the function of NTA has begun to be slowly elucidated, and this includes the modulation of protein-protein interaction, protein-stability, protein function, and protein targeting to specific cellular compartments. Many of these functions have been studied in the context of Naa10/NatA; however, we are only starting to really understand the full complexity of this picture. Roughly, about 40% of all human proteins are substrates of Naa10 and the impact of this modification has only been studied for a few of them. Besides acting as a NAT in the NatA complex, recently other functions have been linked to Naa10, including post-translational NTA, lysine acetylation, and NAT/KAT-independent functions. Also, recent publications have linked mutations in Naa10 to various diseases, emphasizing the importance of Naa10 research in humans. The recent design and synthesis of the first bisubstrate inhibitors that potently and selectively inhibit the NatA/Naa10 complex, monomeric Naa10, and hNaa50 further increases the toolset to analyze Naa10 function.
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85
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Molecular, Cellular, and Physiological Significance of N-Terminal Acetylation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 316:267-305. [DOI: 10.1016/bs.ircmb.2015.01.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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