Thomas Arnesen

University of Bergen, Bergen, Hordaland, Norway

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Publications (54)311.14 Total impact

  • Henriette Aksnes, Adrian Drazic, Thomas Arnesen
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    ABSTRACT: A recent study links N-terminal acetylation and N-end rule degradation to blood pressure regulation. N-terminal mutants of Rgs2, a key G-protein regulator, are differentially processed by N-terminal acetyltransferases and the two branches of the N-end rule pathway. This leads to an imbalance in the signaling governing blood pressure. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Trends in Biochemical Sciences 05/2015; DOI:10.1016/j.tibs.2015.05.003
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    ABSTRACT: Co-translational 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. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Proteomics 04/2015; DOI:10.1002/pmic.201400575
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    ABSTRACT: N-terminal acetylation is a major and vital protein modification catalyzed by N-terminal acetyltransferases (NATs). NatF, or Nα-acetyltransferase 60 (Naa60), was recently identified as a NAT in multicellular eukaryotes. Here, we find that Naa60 differs from all other known NATs by its Golgi localization. A new membrane topology assay named PROMPT and a selective membrane permeabilization assay established that Naa60 faces the cytosolic side of intracellular membranes. An Nt-acetylome analysis of NAA60-knockdown cells revealed that Naa60, as opposed to other NATs, specifically acetylates transmembrane proteins and has a preference for N termini facing the cytosol. Moreover, NAA60 knockdown causes Golgi fragmentation, indicating an important role in the maintenance of the Golgi's structural integrity. This work identifies a NAT associated with membranous compartments and establishes N-terminal acetylation as a common modification among transmembrane proteins, a thus-far poorly characterized part of the N-terminal acetylome. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    Cell Reports 04/2015; 10(8):1-13. DOI:10.1016/j.celrep.2015.01.053
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    Sylvia Varland, Camilla Osberg, Thomas Arnesen
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    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. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Proteomics 04/2015; DOI:10.1002/pmic.201400619
  • Henriette Aksnes, Kristine Hole, Thomas Arnesen
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    ABSTRACT: Protein N-terminal acetylation is catalyzed by N-terminal acetyltransferases and represents one of the most common protein modifications in eukaryotes. An increasing number of studies report on the importance of N-terminal acetylation for protein degradation, complex formation, subcellular targeting, and protein folding. N-terminal acetyltransferases are recognized to play important roles in a diversity of cellular processes like apoptosis, cell proliferation, sister chromatid cohesion, and chromatin silencing and are even linked to the development of rare genetic disorders and cancer. This article summarizes our current knowledge on the implications of N-terminal acetylation at the protein, cellular, and physiological levels. Copyright © 2015 Elsevier Inc. All rights reserved.
    International review of cell and molecular biology 02/2015; 316. DOI:10.1016/bs.ircmb.2015.01.001
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    ABSTRACT: Recent studies revealed the power of whole-exome sequencing to identify mutations in sporadic cases with non-syndromic intellectual disability. We now identified de novo missense variants in NAA10 in two unrelated individuals, a boy and a girl, with severe global developmental delay but without any major dysmorphism by trio whole-exome sequencing. Both de novo variants were predicted to be deleterious, and we excluded other variants in this gene. This X-linked gene encodes N-alpha-acetyltransferase 10, the catalytic subunit of the NatA complex involved in multiple cellular processes. A single hypomorphic missense variant p.(Ser37Pro) was previously associated with Ogden syndrome in eight affected males from two different families. This rare disorder is characterized by a highly recognizable phenotype, global developmental delay and results in death during infancy. In an attempt to explain the discrepant phenotype, we used in vitro N-terminal acetylation assays which suggested that the severity of the phenotype correlates with the remaining catalytic activity. The variant in the Ogden syndrome patients exhibited a lower activity than the one seen in the boy with intellectual disability, while the variant in the girl was the most severe exhibiting only residual activity in the acetylation assays used. We propose that N-terminal acetyltransferase deficiency is clinically heterogeneous with the overall catalytic activity determining the phenotypic severity.European Journal of Human Genetics advance online publication, 6 August 2014; doi:10.1038/ejhg.2014.150.
    European journal of human genetics: EJHG 08/2014; 23(5). DOI:10.1038/ejhg.2014.150
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    ABSTRACT: The X-linked lethal Ogden syndrome was the first reported human genetic disorder associated with a mutation in an N-terminal acetyltransferase (NAT) gene. The affected males harbour a Ser37Pro mutation in the gene encoding hNaa10, the catalytic subunit of NatA, the major human NAT involved in the co-translational acetylation of proteins. Structural models and molecular dynamics simulations of the human NatA and its Ser37Pro mutant highlight differences in regions involved in catalysis and at the interface between hNaa10 and the auxiliary subunit hNaa15. Biochemical data further demonstrate a reduced catalytic capacity and an impaired interaction between hNaa10 Ser37Pro and hNaa15 as well as hNaa50 (NatE), another interactor of the NatA complex. N-terminal acetylome analyses revealed a decreased acetylation of a subset of NatA and NatE substrates in Ogden syndrome cells, supporting the genetic findings and our hypothesis regarding reduced Nt-acetylation of a subset of NatA/NatE-type substrates as one etiology for Ogden Syndrome. Furthermore, Ogden syndrome fibroblasts display abnormal cell migration and proliferation capacity, possibly linked to a perturbed Retinoblastoma pathway. N-terminal acetylation clearly plays a role in Ogden syndrome, thus revealing the in vivo importance of N-terminal acetylation in human physiology and disease. © The Author 2014. Published by Oxford University Press.
    Human Molecular Genetics 03/2014; 24(7). DOI:10.1093/hmg/ddu611
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    ABSTRACT: N-terminal acetylation (Nt-acetylation) occurs on the majority of eukaryotic proteins and is catalysed by N-terminal acetyltransferases (NATs). Nt-acetylation is increasingly recognized as a vital modification with functional implications ranging from protein degradation to protein localization. Very recently, the first human genetic disorder caused by a mutation in a NAT gene was reported; boys diagnosed with the X-linked Ogden syndrome harbour a p.Ser37Pro (S37P) mutation in the gene encoding Naa10, the catalytic subunit of the NatA complex, and suffer from global developmental delays and lethality during infancy. Here, we describe a Saccharomyces cerevisiae model developed by introducing the human wild-type or mutant NatA complex into yeast lacking NatA (NatA-). The wild-type human NatA complex phenotypically complemented the NatA- strain, while only a partial rescue was observed for the Ogden mutant NatA complex suggesting that hNaa10 S37P is only partially functional in vivo. Immunoprecipitation experiments revealed a reduced subunit complexation for the mutant hNatA S37P next to a reduced in vitro catalytic activity. We performed quantitative Nt-acetylome analyses on a control yeast strain (yNatA), a yeast NatA deletion strain (yNatA-), a yeast NatA deletion strain expressing wild-type human NatA (hNatA), and a yeast NatA deletion strain expressing mutant human NatA (hNatA S37P). Interestingly, a generally reduced degree of Nt-acetylation was observed among a large group of NatA substrates in the yeast expressing mutant hNatA as compared to yeast expressing wild-type hNatA. Combined, these data provide strong support for the functional impairment of hNaa10 S37P in vivo and suggest that reduced Nt-acetylation of one or more target substrates contributes to the pathogenesis of the Ogden syndrome. Comparative analysis between human and yeast NatA also provided new insights into the co-evolution of the NatA complexes and their substrates. For instance, (Met-)Ala- N-termini are more prevalent in the human proteome as compared to the yeast proteome, and hNatA displays a preference towards these N-termini as compared to yNatA.
    Molecular &amp Cellular Proteomics 01/2014; 13(8). DOI:10.1074/mcp.M113.035402
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    ABSTRACT: The genetic background of aldosterone producing corticoadrenal adenoma, also called aldosterone-producing adenomas (APAs), has been poorly studied until recently when mutations in the genes KCNJ5, ATP1A1 and ATP2B3 were reported. The aim of the study was to investigate the frequency of mutations in KCNJ5, KCNJ3, ATP1A1, and ATP2B3 in a series of APAs from Norway, Sweden and Germany. We sequenced the pore region of KCNJ5, ATP1A1 and ATP2B3 in 35 non-familial APAs. Out of 35 cases, 11 (31%) were found to have KCNJ5 mutations, 2 (6%) had mutations in ATP1A1 and 3 (9%) in ATP2B3. KCNJ5 mutations were found at the same codons as reported earlier, c.451G>A (p.G151R), c.451G>C (p.G151R) and c.503T>G (p.L168R), which may represent a mutational hot spot region. ATP1A1 and ATP2B3 mutations were identified at c.311T>G (p.L104R) as well as at c.1272_1277delGCTGGT and c.1281_1286delGGCTGT, respectively. Of note, the latter mutation has not been reported before. All identified mutations were somatic and complementary to each other. Of interest, there seems to be a tendency that APAs with mutations in ATP1A1 and ATP2B3 seem to be smaller than APAs with KCNJ5 mutations. In summary, hot spot mutations in KCNJ5, ATP1A1 and ATP2B were identified in 46% of the APAs analyzed in this study. All mutations identified in KCNJ5 were located in proximity to the filter selective channel. The mutations identified in ATP1A1 and ATP2B3 were close to the ion-binding domain. In these cases, the mutations are predicted to lead to loss of the ion gating activity of the protein.
    Endocrine Related Cancer 10/2013; 21(1). DOI:10.1530/ERC-13-0466
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    ABSTRACT: N-terminal acetylation is ubiquitous among eukaryotic proteins and controls a myriad of biological processes. Of the N-terminal acetyltransferases (NATs) that facilitate this cotranslational modification, the heterodimeric NatA complex has the most diversity for substrate selection and modifies the majority of all N-terminally acetylated proteins. Here, we report the X-ray crystal structure of the 100-kDa holo-NatA complex from Schizosaccharomyces pombe, in the absence and presence of a bisubstrate peptide-CoA-conjugate inhibitor, as well as the structure of the uncomplexed Naa10p catalytic subunit. The NatA-Naa15p auxiliary subunit contains 13 tetratricopeptide motifs and adopts a ring-like topology that wraps around the NatA-Naa10p subunit, an interaction that alters the Naa10p active site for substrate-specific acetylation. These studies have implications for understanding the mechanistic details of other NAT complexes and how regulatory subunits modulate the activity of the broader family of protein acetyltransferases.
    Nature Structural & Molecular Biology 08/2013; DOI:10.1038/nsmb.2636
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    ABSTRACT: BACKGROUND: Primary aldosteronism (PA) is a frequent cause (about 10 %) of hypertension. Some cases of PA were recently found to be caused by mutations in the potassium channel KCNJ5. Our objective was to determine the mutation status of KCNJ5 and seven additional candidate genes for tumorigenesis: YY1, FZD4, ARHGAP9, ZFP37, KDM5C, LRP1B, and PDE9A and, furthermore, the surgical outcome of PA patients who underwent surgery in Western Norway. METHODS: Twenty-eight consecutive patients with aldosterone-producing adrenal tumors (20 patients with single adenoma, 8 patients with unilateral multiple adenomas or hyperplasia) who underwent surgery were included in this study. All patients were operated on by uncomplicated laparoscopic total adrenalectomy. Genomic DNA was isolated from tumor and non-tumor adrenocortical tissue, and DNA sequencing revealed the mutation status. RESULTS: Ten out of 28 (36 %) patients with PA displayed tumor mutations in KCNJ5 (p. G151R and L168R) while none were found in the corresponding non-tumor samples. No mutations were found in the other seven candidate genes screened. The presence of KCNJ5 mutations was associated with lower blood pressure and a higher chance for cure by surgery when compared to patients harboring the KCNJ5 wild type. CONCLUSIONS: KCNJ5 mutations are associated with a better surgical outcome. Preoperative identification of the mutation status might have impact on surgical strategy (total vs. subtotal adrenalectomy).
    Langenbeck s Archives of Surgery 06/2013; DOI:10.1007/s00423-013-1093-2
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    Henriette Aksnes, Camilla Osberg, Thomas Arnesen
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    ABSTRACT: N-terminal acetylation has been suggested to play a role in the subcellular targeting of proteins, in particular those acetylated by the N-terminal acetyltransferase complex NatC. Based on previous positional proteomics data revealing N-terminal acetylation status and the predicted NAT substrate classes, we selected 13 suitable NatC substrates for subcellular localization studies in Saccharomyces cerevisiae. Fluorescence microscopy analysis of GFP-tagged candidates in the presence or absence of the NatC catalytic subunit Naa30 (Mak3) revealed unaltered localization patterns for all 13 candidates, thus arguing against a general role for the N-terminal acetyl group as a localization determinant. Furthermore, all organelle-localized substrates indicated undisrupted structures, thus suggesting that absence of NatC acetylation does not have a vast effect on organelle morphology in yeast.
    PLoS ONE 04/2013; 8(4):e61012. DOI:10.1371/journal.pone.0061012
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    ABSTRACT: The N-termini of 80-90% of human proteins are acetylated by the N-terminal acetyltransferases (NATs), NatA-NatF. The major NAT complex, NatA, and particularly the catalytic subunit hNaa10 (ARD1) has been implicated in cancer development. For example, knockdown of hNaa10 results in cancer cell death and the arrest of cell proliferation. It also sensitized cancer cells to drug-induced cytotoxicity. Human NatE has a distinct substrate specificity and is essential for normal chromosome segregation. Thus, NAT inhibitors may potentially be valuable anticancer therapeutics, either directly or as adjuvants. Herein, we report the design and synthesis of the first inhibitors targeting these enzymes. Using the substrate specificity of the enzymes as a guide, we synthesized three bisubstrate analogues that potently and selectively inhibit the NatA complex (CoA-Ac-SES4; IC50 = 15.1 μM), hNaa10, the catalytic subunit of NatA (CoA-Ac-EEE4; Ki = 1.6 μM), and NatE/hNaa50 (CoA-Ac-MLG7; Ki* = 8 nM); CoA-Ac-EEE4 is a reversible competitive inhibitor of hNaa10, and CoA-Ac-MLG7 is a slow tight binding inhibitor of hNaa50. Our demonstration that it is possible to develop NAT selective inhibitors should assist future efforts to develop NAT inhibitors with more drug-like properties that can be used to chemically interrogate in vivo NAT function.
    ACS Chemical Biology 04/2013; 8(6). DOI:10.1021/cb400136s
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    ABSTRACT: Maturation of protein N-termini occurs in all kingdoms of life, with major protein modifications being proteolytic processing (e.g., removal of initiator methionines) and N-terminal acetylation. The functional consequences of these modifications are only known for a few substrates, and techniques to study such modifications have begun to emerge only recently. We here report on a method enabling targeted, mass spectrometry based analysis of protein N-termini from polyacrylamide gel-separated proteins. In our method, stable isotope incorporation by in-gel N-acetylation of free primary amines permits calculating the extent of in vivo N-terminal acetylation, proven to reveal crucial information with reference to N-terminal protein biology.
    Methods in molecular biology (Clifton, N.J.) 01/2013; 981:115-26. DOI:10.1007/978-1-62703-305-3_9
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    ABSTRACT: Protein N-terminal acetylation is a widespread modification in eukaryotes catalyzed by N-terminal acetyltransferases (NATs). The various NATs and their specific substrate specificities and catalytic mechanisms are far from fully understood. We here describe an in vitro method based on reverse-phase HPLC to quantitatively measure in vitro acetylation of NAT oligopeptide substrates, enabling the determination of NAT specificity as well as kinetic parameters.
    Methods in molecular biology (Clifton, N.J.) 01/2013; 981:95-102. DOI:10.1007/978-1-62703-305-3_7
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    ABSTRACT: Nt-acetylation is among the most common protein modifications in eukaryotes. Although thought for a long time to protect proteins from degradation, the role of Nt-acetylation is still debated. It is catalyzed by enzymes called N-terminal acetyltransferases (NATs). In eukaryotes, several NATs, composed of at least one catalytic domain, target different substrates based on their N-terminal sequences. In order to better understand the substrate specificity of human NATs, we investigated in silico the enzyme-substrate interactions in four catalytic subunits of human NATs (Naa10p, Naa20p, Naa30p and Naa50p). To date hNaa50p is the only human subunit for which X-ray structures are available. We used the structure of the ternary hNaa50p/AcCoA/MLG complex and a structural model of hNaa10p as a starting point for multiple molecular dynamics simulations of hNaa50p/AcCoA/substrate (substrate = MLG, EEE, MKG), hNaa10p/AcCoA/substrate (substrate = MLG, EEE). Nine alanine point-mutants of the hNaa50p/AcCoA/MLG complex were also simulated. Homology models of hNaa20p and hNaa30p were built and compared to hNaa50p and hNaa10p. The simulations of hNaa50p/AcCoA/MLG reproduce the interactions revealed by the X-ray data. We observed strong hydrogen bonds between MLG and tyrosines 31, 138 and 139. Yet the tyrosines interacting with the substrate's backbone suggest that their role in specificity is limited. This is confirmed by the simulations of hNaa50p/AcCoA/EEE and hNaa10p/AcCoA/MLG, where these hydrogen bonds are still observed. Moreover these tyrosines are all conserved in hNaa20p and hNaa30p. Other amino acids tune the specificity of the S1' sites that is different for hNaa10p (acidic), hNaa20p (hydrophobic/basic), hNaa30p (basic) and hNaa50p (hydrophobic). We also observe dynamic correlation between the ligand binding site and helix [Formula: see text] that tightens under substrate binding. Finally, by comparing the four structures we propose maps of the peptide-enzyme interactions that should help rationalizing substrate-specificity and lay the ground for inhibitor design.
    PLoS ONE 12/2012; 7(12):e52642. DOI:10.1371/journal.pone.0052642
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    ABSTRACT: N-terminal acetylation (Nt-acetylation) is a highly abundant protein modification in eukaryotes catalysed by N-terminal acetyltransferases (NATs), which transfer an acetyl group from acetyl coenzyme A to the alpha amino group of a nascent polypeptide. Nt-acetylation has emerged as an important protein modifier, steering protein degradation, protein complex formation and protein localization. Very recently, it was reported that some human proteins could carry a propionyl group at their N-terminus. Here, we investigated the generality of N-terminal propionylation by analysing its proteome-wide occurrence in yeast and we identified 10 unique in vivo Nt-propionylated N-termini. Furthermore, by performing differential N-terminome analysis of a control yeast strain (yNatA), a yeast NatA deletion strain (yNatA) or a yeast NatA deletion strain expressing human NatA (hNatA), we were able to demonstrate that in vivo Nt-propionylation of several proteins, displaying a NatA type substrate specificity profile, depended on the presence of either yeast or human NatA. Furthermore, in vitro Nt-propionylation assays using synthetic peptides, propionyl coenzyme A, and either purified human NATs or immunoprecipitated human NatA, clearly demonstrated that NATs are Nt-propionyltransferases (NPTs) per se. We here demonstrate for the first time that Nt-propionylation can occur in yeast and thus is an evolutionarily conserved process, and that the NATs are multifunctional enzymes acting as NPTs in vivo and in vitro, in addition to their main role as NATs, and their potential function as lysine acetyltransferases (KATs) and non-catalytic regulators.
    Molecular &amp Cellular Proteomics 10/2012; DOI:10.1074/mcp.M112.019299
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    ABSTRACT: Protein N-terminal acetylation (Nt-acetylation) is an important mediator of protein function, stability, sorting, and localization. Although the responsible enzymes are thought to be fairly well characterized, the lack of identified in vivo substrates, the occurrence of Nt-acetylation substrates displaying yet uncharacterized N-terminal acetyltransferase (NAT) specificities, and emerging evidence of posttranslational Nt-acetylation, necessitate the use of genetic models and quantitative proteomics. NatB, which targets Met-Glu-, Met-Asp-, and Met-Asn-starting protein N termini, is presumed to Nt-acetylate 15% of all yeast and 18% of all human proteins. We here report on the evolutionary traits of NatB from yeast to human and demonstrate that ectopically expressed hNatB in a yNatB-Δ yeast strain partially complements the natB-Δ phenotypes and partially restores the yNatB Nt-acetylome. Overall, combining quantitative N-terminomics with yeast studies and knockdown of hNatB in human cell lines, led to the unambiguous identification of 180 human and 110 yeast NatB substrates. Interestingly, these substrates included Met-Gln- N-termini, which are thus now classified as in vivo NatB substrates. We also demonstrate the requirement of hNatB activity for maintaining the structure and function of actomyosin fibers and for proper cellular migration. In addition, expression of tropomyosin-1 restored the altered focal adhesions and cellular migration defects observed in hNatB-depleted HeLa cells, indicative for the conserved link between NatB, tropomyosin, and actin cable function from yeast to human.
    Proceedings of the National Academy of Sciences 07/2012; 109(31):12449-54. DOI:10.1073/pnas.1210303109
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    ABSTRACT: The majority of eukaryotic proteins are subjected to N-terminal acetylation (Nt-acetylation), catalysed by N-terminal acetyltransferases (NATs). Recently, the structure of an NAT-peptide complex was determined, and detailed proteome-wide Nt-acetylation patterns were revealed. Furthermore, Nt-acetylation just emerged as a multifunctional regulator, acting as a protein degradation signal, an inhibitor of endoplasmic reticulum (ER) translocation, and a mediator of protein complex formation. Nt-acetylation is regulated by acetyl-coenzyme A (Ac-CoA) levels, and thereby links metabolic cell states to cell death. The essentiality of NATs in humans is stressed by the recent discovery of a human hereditary lethal disease caused by a mutation in an NAT gene. Here, we discuss how these recent findings shed light on NATs as major protein regulators and key cellular players.
    Trends in Biochemical Sciences 03/2012; 37(4):152-61. DOI:10.1016/j.tibs.2012.02.003
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    T V Kalvik, T Arnesen
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    ABSTRACT: The human N-terminal acetyltransferases (NATs) catalyze the transfer of acetyl moieties to the N-termini of 80-90% of all human proteins. Six NAT types are present in humans, NatA-NatF, each is composed of specific subunits and each acetylates a set of substrates defined by the N-terminal amino-acid sequence. NATs have been suggested to act as oncoproteins as well as tumor suppressors in human cancers, and NAT expression may be both elevated and decreased in cancer versus non-cancer tissues. Manipulation of NATs in cancer cells induced cell-cycle arrest, apoptosis or autophagy, implying that these enzymes target a variety of pathways. Of particular interest is hNaa10p (human ARD1), the catalytic subunit of the NatA complex, which was coupled to a number of signaling molecules including hypoxia inducible factor-1α, β-catenin/cyclin D1, TSC2/mammalian target of rapamycin, myosin light chain kinase , DNA methyltransferase1/E-cadherin and p21-activated kinase-interacting exchange factors (PIX)/Cdc42/Rac1. The variety of mechanistic links where hNaa10p acts as a NAT, a lysine acetyltransferase or displaying a non-catalytic role, provide insights to how hNaa10p may act as both a tumor suppressor and oncoprotein.Oncogene advance online publication, 5 March 2012; doi:10.1038/onc.2012.82.
    Oncogene 03/2012; 32(3). DOI:10.1038/onc.2012.82

Publication Stats

1k Citations
311.14 Total Impact Points

Institutions

  • 2005–2015
    • University of Bergen
      • • Department of Molecular Biology
      • • Department of Surgical Sciences
      Bergen, Hordaland, Norway
  • 2013
    • Haukeland University Hospital
      Bergen, Hordaland, Norway
  • 2011–2013
    • Vlaams Instituut voor Biotechnologie
      Gand, Flemish, Belgium
    • University of Utah
      • Department of Pediatrics
      Salt Lake City, UT, United States