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Halwas K, Döring LM, Oehlert FV, Dohmen RJ. Hypusinated eIF5A Promotes Ribosomal Frameshifting during Decoding of ODC Antizyme mRNA in Saccharomyces cerevisiae. Int J Mol Sci 2022; 23:ijms232112972. [PMID: 36361762 PMCID: PMC9656687 DOI: 10.3390/ijms232112972] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/24/2022] Open
Abstract
Polyamines are essential biogenic poly-cations with important roles in many cellular processes and diseases such as cancer. A rate-limiting step early in the biosynthesis of polyamines is the conversion of ornithine to putrescine by the homodimeric enzyme ornithine decarboxylase (ODC). In a conserved mechanism of posttranslational regulation, ODC antizyme (OAZ) binds to ODC monomers promoting their ubiquitin-independent degradation by the proteasome. Decoding of OAZ mRNA is unusual in that it involves polyamine-regulated bypassing of an internal translation termination (STOP) codon by a ribosomal frameshift (RFS) event. Using Saccharomyces cerevisiae, we earlier showed that high polyamine concentrations lead to increased efficiency of OAZ1 mRNA translation by binding to nascent Oaz1 polypeptide. The binding of polyamines prevents stalling of the ribosomes on OAZ1 mRNA caused by nascent Oaz1 polypeptide thereby promoting synthesis of full-length Oaz1. Polyamine depletion, however, also inhibits RFS during the decoding of constructs bearing the OAZ1 shift site lacking sequences encoding the Oaz1 parts implicated in polyamine binding. Polyamine depletion is known to impair hypusine modification of translation factor eIF5A. Using a novel set of conditional mutants impaired in the function of eIF5A/Hyp2 or its hypusination, we show here that hypusinated eIF5A is required for efficient translation across the OAZ1 RFS site. These findings identify eIF5A as a part of Oaz1 regulation, and thereby of polyamine synthesis. Additional experiments with DFMO, however, show that depletion of polyamines inhibits translation across the OAZ1 RFS site not only by reducing Hyp2 hypusination, but in addition, and even earlier, by affecting RFS more directly.
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Park MH, Kar RK, Banka S, Ziegler A, Chung WK. Post-translational formation of hypusine in eIF5A: implications in human neurodevelopment. Amino Acids 2022; 54:485-499. [PMID: 34273022 PMCID: PMC9117371 DOI: 10.1007/s00726-021-03023-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 06/15/2021] [Indexed: 01/04/2023]
Abstract
Hypusine [Nε-(4-amino-2-hydroxybutyl)lysine] is a derivative of lysine that is formed post-translationally in the eukaryotic initiation factor 5A (eIF5A). Its occurrence at a single site in one cellular protein defines hypusine synthesis as one of the most specific post-translational modifications. Synthesis of hypusine involves two enzymatic steps: first, deoxyhypusine synthase (DHPS) cleaves the 4-aminobutyl moiety of spermidine and transfers it to the ε-amino group of a specific lysine residue of the eIF5A precursor protein to form an intermediate, deoxyhypusine [Nε-(4-aminobutyl)lysine]. This intermediate is subsequently hydroxylated by deoxyhypusine hydroxylase (DOHH) to form hypusine in eIF5A. eIF5A, DHPS, and DOHH are highly conserved in all eukaryotes, and both enzymes exhibit a strict specificity toward eIF5A substrates. eIF5A promotes translation elongation globally by alleviating ribosome stalling and it also facilitates translation termination. Hypusine is required for the activity of eIF5A, mammalian cell proliferation, and animal development. Homozygous knockout of any of the three genes, Eif5a, Dhps, or Dohh, leads to embryonic lethality in mice. eIF5A has been implicated in various human pathological conditions. A recent genetic study reveals that heterozygous germline EIF5A variants cause Faundes-Banka syndrome, a craniofacial-neurodevelopmental malformations in humans. Biallelic variants of DHPS were identified as the genetic basis underlying a rare inherited neurodevelopmental disorder. Furthermore, biallelic DOHH variants also appear to be associated with neurodevelopmental disorder. The clinical phenotypes of these patients include intellectual disability, developmental delay, seizures, microcephaly, growth impairment, and/or facial dysmorphisms. Taken together, these findings underscore the importance of eIF5A and the hypusine modification pathway in neurodevelopment in humans.
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Affiliation(s)
- Myung Hee Park
- Molecular and Cellular Biochemistry Section, NIDCR, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Rajesh Kumar Kar
- Molecular and Cellular Biochemistry Section, NIDCR, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Siddharth Banka
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester, M13 9WL, UK
| | - Alban Ziegler
- Department of Genetics, University of Angers, Angers, France
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Han X, Shangguan J, Wang Z, Li Y, Fan J, Ren A, Zhao M. Spermidine Regulates Mitochondrial Function by Enhancing eIF5A Hypusination and Contributes to Reactive Oxygen Species Production and Ganoderic Acid Biosynthesis in Ganoderma lucidum. Appl Environ Microbiol 2022; 88:e0203721. [PMID: 35108082 PMCID: PMC8939328 DOI: 10.1128/aem.02037-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/24/2022] [Indexed: 11/20/2022] Open
Abstract
Spermidine, a kind of polycation and one important member of the polyamine family, is essential for survival in many kinds of organisms and participates in the regulation of cell growth and metabolism. To explore the mechanism by which spermidine regulates ganoderic acid (GA) biosynthesis in Ganoderma lucidum, the effects of spermidine on GA and reactive oxygen species (ROS) contents were examined. Our data suggested that spermidine promoted the production of mitochondrial ROS and positively regulated GA biosynthesis. Further research revealed that spermidine promoted the translation of mitochondrial complexes I and II and subsequently influenced their activity. With a reduction in eukaryotic translation initiation factor 5A (eIF5A) hypusination by over 50% in spermidine synthase gene (spds) knockdown strains, the activities of mitochondrial complexes I and II were reduced by nearly 60% and 80%, respectively, and the protein contents were reduced by over 50%, suggesting that the effect of spermidine on mitochondrial complexes I and II was mediated through its influence on eIF5A hypusination. Furthermore, after knocking down eIF5A, the deoxyhypusine synthase gene (dhs), and the deoxyhypusine hydroxylase gene (dohh), the mitochondrial ROS level was reduced by nearly 50%, and the GA content was reduced by over 40%, suggesting that eIF5A hypusination contributed to mitochondrial ROS production and GA biosynthesis. In summary, spermidine maintains mitochondrial ROS homeostasis by regulating the translation and subsequent activity of complexes I and II via eIF5A hypusination and promotes GA biosynthesis via mitochondrial ROS signaling. The present findings provide new insight into the spermidine-mediated biosynthesis of secondary metabolites. IMPORTANCE Spermidine is necessary for organism survival and is involved in the regulation of various biological processes. However, the specific mechanisms underlying the various physiological functions of spermidine are poorly understood, especially in microorganisms. In this study, we found that spermidine hypusinates eIF5A to promote the production of mitochondrial ROS and subsequently regulate secondary metabolism in microorganisms. Our study provides a better understanding of the mechanism by which spermidine regulates mitochondrial function and provides new insight into the spermidine-mediated biosynthesis of secondary metabolites.
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Affiliation(s)
- Xiaofei Han
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Jiaolei Shangguan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Zi Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Yu Li
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Junpei Fan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Ang Ren
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Mingwen Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
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Barba-Aliaga M, Alepuz P. Role of eIF5A in Mitochondrial Function. Int J Mol Sci 2022; 23:1284. [PMID: 35163207 PMCID: PMC8835957 DOI: 10.3390/ijms23031284] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/19/2022] [Accepted: 01/21/2022] [Indexed: 12/17/2022] Open
Abstract
The eukaryotic translation initiation factor 5A (eIF5A) is an evolutionarily conserved protein that binds ribosomes to facilitate the translation of peptide motifs with consecutive prolines or combinations of prolines with glycine and charged amino acids. It has also been linked to other molecular functions and cellular processes, such as nuclear mRNA export and mRNA decay, proliferation, differentiation, autophagy, and apoptosis. The growing interest in eIF5A relates to its association with the pathogenesis of several diseases, including cancer, viral infection, and diabetes. It has also been proposed as an anti-aging factor: its levels decay in aged cells, whereas increasing levels of active eIF5A result in the rejuvenation of the immune and vascular systems and improved brain cognition. Recent data have linked the role of eIF5A in some pathologies with its function in maintaining healthy mitochondria. The eukaryotic translation initiation factor 5A is upregulated under respiratory metabolism and its deficiency reduces oxygen consumption, ATP production, and the levels of several mitochondrial metabolic enzymes, as well as altering mitochondria dynamics. However, although all the accumulated data strongly link eIF5A to mitochondrial function, the precise molecular role and mechanisms involved are still unknown. In this review, we discuss the findings linking eIF5A and mitochondria, speculate about its role in regulating mitochondrial homeostasis, and highlight its potential as a target in diseases related to energy metabolism.
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Affiliation(s)
- Marina Barba-Aliaga
- Instituto de Biotecnología y Biomedicina (Biotecmed), Universitat de València, 46100 València, Spain
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, 46100 València, Spain
| | - Paula Alepuz
- Instituto de Biotecnología y Biomedicina (Biotecmed), Universitat de València, 46100 València, Spain
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, 46100 València, Spain
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Becker AE, Wu PK, Park JI. eIF5A-Independent Role of DHPS in p21 CIP1 and Cell Fate Regulation. Int J Mol Sci 2021; 22:13187. [PMID: 34947982 PMCID: PMC8707118 DOI: 10.3390/ijms222413187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 11/30/2022] Open
Abstract
Deoxyhypusine synthase (DHPS) catalyzes the first step of hypusination of the elongation translation factor 5A (eIF5A), and these two proteins have an exclusive enzyme-substrate relationship. Here we demonstrate that DHPS has a role independent of eIF5A hypusination in A375 and SK-MEL-28 human melanoma cells, in which the extracellular signal regulated kinase 1/2 (ERK1/2) pathway is deregulated. We found that RNA interference of DHPS induces G0/G1 cell cycle arrest in association with increased p21CIP1 expression in these cells whereas eIF5A knockdown induces cell death without increasing p21CIP1 expression. Interestingly, p21CIP1 knockdown switched DHPS knockdown-induced growth arrest to cell death in these cells, suggesting a specific relation between DHPS and p21CIP1 in determining cell fate. Surprisingly, ectopic expression of DHPS-K329R mutant that cannot hypusinate eIF5A abrogated DHPS knockdown-induced p21CIP1 expression in these cells, suggesting a non-canonical role of DHPS underlying the contrasting effects of DHPS and eIF5A knockdowns. We also show that DHPS knockdown induces p21CIP1 expression in these cells by increasing CDKN1A transcription through TP53 and SP1 in an ERK1/2-dependent manner. These data suggest that DHPS has a role independent of its ability to hypusinate eIF5A in cells, which appears to be important for regulating p21CIP1 expression and cell fate.
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Affiliation(s)
| | | | - Jong-In Park
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA; (A.E.B.); (P.-K.W.)
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McNamara KM, Gobert AP, Wilson KT. The role of polyamines in gastric cancer. Oncogene 2021; 40:4399-4412. [PMID: 34108618 PMCID: PMC8262120 DOI: 10.1038/s41388-021-01862-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/07/2021] [Accepted: 05/24/2021] [Indexed: 02/05/2023]
Abstract
Advancements in our understanding of polyamine molecular and cellular functions have led to increased interest in targeting polyamine metabolism for anticancer therapeutic benefits. The polyamines putrescine, spermidine, and spermine are polycationic alkylamines commonly found in all living cells and are essential for cellular growth and survival. This review summarizes the existing research on polyamine metabolism and function, specifically the role of polyamines in gastric immune cell and epithelial cell function. Polyamines have been implicated in a multitude of cancers, but in this review, we focus on the role of polyamine dysregulation in the context of Helicobacter pylori-induced gastritis and subsequent progression to gastric cancer. Due to the emerging implication of polyamines in cancer development, there is an increasing number of promising clinical trials using agents to target the polyamine metabolic pathway for potential chemoprevention and anticancer therapy.
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Affiliation(s)
- Kara M. McNamara
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA,Program in Cancer Biology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alain P. Gobert
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA,Center for Mucosal Inflammation and Cancer, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Keith T. Wilson
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA,Program in Cancer Biology, Vanderbilt University Medical Center, Nashville, TN, USA,Center for Mucosal Inflammation and Cancer, Vanderbilt University Medical Center, Nashville, TN, USA,Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA,Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA
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Iron in Translation: From the Beginning to the End. Microorganisms 2021; 9:microorganisms9051058. [PMID: 34068342 PMCID: PMC8153317 DOI: 10.3390/microorganisms9051058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 12/16/2022] Open
Abstract
Iron is an essential element for all eukaryotes, since it acts as a cofactor for many enzymes involved in basic cellular functions, including translation. While the mammalian iron-regulatory protein/iron-responsive element (IRP/IRE) system arose as one of the first examples of translational regulation in higher eukaryotes, little is known about the contribution of iron itself to the different stages of eukaryotic translation. In the yeast Saccharomyces cerevisiae, iron deficiency provokes a global impairment of translation at the initiation step, which is mediated by the Gcn2-eIF2α pathway, while the post-transcriptional regulator Cth2 specifically represses the translation of a subgroup of iron-related transcripts. In addition, several steps of the translation process depend on iron-containing enzymes, including particular modifications of translation elongation factors and transfer RNAs (tRNAs), and translation termination by the ATP-binding cassette family member Rli1 (ABCE1 in humans) and the prolyl hydroxylase Tpa1. The influence of these modifications and their correlation with codon bias in the dynamic control of protein biosynthesis, mainly in response to stress, is emerging as an interesting focus of research. Taking S. cerevisiae as a model, we hereby discuss the relevance of iron in the control of global and specific translation steps.
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Zarechenskaia AS, Sergiev PV, Osterman IA. Quality Control Mechanisms in Bacterial Translation. Acta Naturae 2021; 13:32-44. [PMID: 34377554 PMCID: PMC8327144 DOI: 10.32607/actanaturae.11401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/15/2021] [Indexed: 12/24/2022] Open
Abstract
Ribosome stalling during translation significantly reduces cell viability, because cells have to spend resources on the synthesis of new ribosomes. Therefore, all bacteria have developed various mechanisms of ribosome rescue. Usually, the release of ribosomes is preceded by hydrolysis of the tRNA-peptide bond, but, in some cases, the ribosome can continue translation thanks to the activity of certain factors. This review describes the mechanisms of ribosome rescue thanks to trans-translation and the activity of the ArfA, ArfB, BrfA, ArfT, HflX, and RqcP/H factors, as well as continuation of translation via the action of EF-P, EF-4, and EttA. Despite the ability of some systems to duplicate each other, most of them have their unique functional role, related to the quality control of bacterial translation in certain abnormalities caused by mutations, stress cultivation conditions, or antibiotics.
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Affiliation(s)
- A. S. Zarechenskaia
- Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics and Belozersky Institute of Physico-Chemical Biology, Moscow, 119992 Russia
| | - P. V. Sergiev
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, 143028 Russia
- Lomonosov Moscow State University, Institute of functional genomics, Moscow, 119992 Russia
- Lomonosov Moscow State University, Department of Chemistry, Moscow, 119992 Russia
| | - I. A. Osterman
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, 143028 Russia
- Lomonosov Moscow State University, Department of Chemistry, Moscow, 119992 Russia
- Sirius University of Science and Technology, Genetics and Life Sciences Research Center, Sochi, 354340 Russia
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Liang S, Dong H, Zhu S, Zhao Q, Huang B, Yu Y, Wang Q, Wang H, Yu S, Han H. Eimeria tenella Translation Initiation Factor eIF-5A That Interacts With Calcium-Dependent Protein Kinase 4 Is Involved in Host Cell Invasion. Front Cell Infect Microbiol 2021; 10:602049. [PMID: 33553005 PMCID: PMC7862772 DOI: 10.3389/fcimb.2020.602049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/04/2020] [Indexed: 11/17/2022] Open
Abstract
Eimeria tenella is an apicomplexan, parasitic protozoan known to infect poultry worldwide. An important calcium-dependent protein kinase (CDPK) has been identified in plants, green algae, ciliates and apicomplexan, such as E. tenella. CDPKs are effector molecules involved in calcium signaling pathways, which control important physiological processes such as gliding motility, reproduction, and host cell invasion. Given that CDPKs are not found in the host, studying the functions of CDPKs in E. tenella may serve as a basis for developing new therapeutic drugs and vaccines. To assess the function of CDPK4 in E. tenella (EtCDPK4), a putative interactor, translation initiation factor eIF-5A (EteIF-5A), was screened by both co-immunoprecipitation (co-IP) and His pull-down assays followed by mass spectrometry. The interaction between EteIF-5A and EtCDPK4 was determined by bimolecular fluorescence complementation (BiFC), GST pull-down, and co-IP. The molecular characteristics of EteIF-5A were then analyzed. Quantitative real-time polymerase chain reaction and western blotting were used to determine the transcription and protein levels of EteIF-5A in the different developmental stages of E. tenella. The results showed that the transcription level of EteIF-5A mRNA was highest in second-generation merozoites, and the protein expression level was highest in unsporulated oocysts. Indirect immunofluorescence showed that the EteIF-5A protein was found throughout the cytoplasm of sporozoites, but not in the refractile body. As the invasion of DF-1 cells progressed, EteIF-5A fluorescence intensity increased in trophozoites, decreased in immature schizonts, and increased in mature schizonts. The secretion assay results, analyzed by western blotting, indicated that EteIF-5A was a secreted protein but not from micronemes. The results of invasion inhibition assays showed that rabbit anti-rEteIF-5A polyclonal antibodies effectively inhibited cell invasion by sporozoites, with an inhibition rate of 48%.
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Affiliation(s)
- Shanshan Liang
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
- College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Hui Dong
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Shunhai Zhu
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Qiping Zhao
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Bing Huang
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yu Yu
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
- College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Qingjie Wang
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Haixia Wang
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Shuilan Yu
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Hongyu Han
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
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Barba-Aliaga M, Villarroel-Vicente C, Stanciu A, Corman A, Martínez-Pastor MT, Alepuz P. Yeast Translation Elongation Factor eIF5A Expression Is Regulated by Nutrient Availability through Different Signalling Pathways. Int J Mol Sci 2020; 22:E219. [PMID: 33379337 PMCID: PMC7794953 DOI: 10.3390/ijms22010219] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/17/2020] [Accepted: 12/24/2020] [Indexed: 12/15/2022] Open
Abstract
Translation elongation factor eIF5A binds to ribosomes to promote peptide bonds between problematic amino acids for the reaction like prolines. eIF5A is highly conserved and essential in eukaryotes, which usually contain two similar but differentially expressed paralogue genes. The human eIF5A-1 isoform is abundant and implicated in some cancer types; the eIF5A-2 isoform is absent in most cells but becomes overexpressed in many metastatic cancers. Several reports have connected eIF5A and mitochondria because it co-purifies with the organelle or its inhibition reduces respiration and mitochondrial enzyme levels. However, the mechanisms of eIF5A mitochondrial function, and whether eIF5A expression is regulated by the mitochondrial metabolism, are unknown. We analysed the expression of yeast eIF5A isoforms Tif51A and Tif51B under several metabolic conditions and in mutants. The depletion of Tif51A, but not Tif51B, compromised yeast growth under respiration and reduced oxygen consumption. Tif51A expression followed dual positive regulation: by high glucose through TORC1 signalling, like other translation factors, to promote growth and by low glucose or non-fermentative carbon sources through Snf1 and heme-dependent transcription factor Hap1 to promote respiration. Upon iron depletion, Tif51A was down-regulated and Tif51B up-regulated. Both were Hap1-dependent. Our results demonstrate eIF5A expression regulation by cellular metabolic status.
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Affiliation(s)
- Marina Barba-Aliaga
- Instituto Biotecmed, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain; (M.B.-A.); (C.V.-V.); (A.S.); (A.C.)
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
| | - Carlos Villarroel-Vicente
- Instituto Biotecmed, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain; (M.B.-A.); (C.V.-V.); (A.S.); (A.C.)
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
| | - Alice Stanciu
- Instituto Biotecmed, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain; (M.B.-A.); (C.V.-V.); (A.S.); (A.C.)
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
| | - Alba Corman
- Instituto Biotecmed, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain; (M.B.-A.); (C.V.-V.); (A.S.); (A.C.)
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
| | - María Teresa Martínez-Pastor
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
| | - Paula Alepuz
- Instituto Biotecmed, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain; (M.B.-A.); (C.V.-V.); (A.S.); (A.C.)
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain;
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Hummels KR, Kearns DB. Translation elongation factor P (EF-P). FEMS Microbiol Rev 2020; 44:208-218. [PMID: 32011712 DOI: 10.1093/femsre/fuaa003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/30/2020] [Indexed: 01/01/2023] Open
Abstract
Translation elongation factor P (EF-P) is conserved in all three domains of life (called eIF5A and aIF5A in eukaryotes and archaea, respectively) and functions to alleviate ribosome pausing during the translation of specific sequences, including consecutive proline residues. EF-P was identified in 1975 as a factor that stimulated the peptidyltransferase reaction in vitro but its involvement in the translation of tandem proline residues was not uncovered until 2013. Throughout the four decades of EF-P research, perceptions of EF-P function have changed dramatically. In particular, while EF-P was thought to potentiate the formation of the first peptide bond in a protein, it is now broadly accepted to act throughout translation elongation. Further, EF-P was initially reported to be essential, but recent work has shown that the requirement of EF-P for growth is conditional. Finally, it is thought that post-translational modification of EF-P is strictly required for its function but recent studies suggest that EF-P modification may play a more nuanced role in EF-P activity. Here, we review the history of EF-P research, with an emphasis on its initial isolation and characterization as well as the discoveries that altered our perceptions of its function.
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Affiliation(s)
| | - Daniel B Kearns
- Department of Biology, Indiana University, Bloomington, IN USA
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12
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Silva SF, Klippel AH, Ramos PZ, Santiago ADS, Valentini SR, Bengtson MH, Massirer KB, Bilsland E, Couñago RM, Zanelli CF. Structural features and development of an assay platform of the parasite target deoxyhypusine synthase of Brugia malayi and Leishmania major. PLoS Negl Trop Dis 2020; 14:e0008762. [PMID: 33044977 PMCID: PMC7581365 DOI: 10.1371/journal.pntd.0008762] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 10/22/2020] [Accepted: 08/31/2020] [Indexed: 01/03/2023] Open
Abstract
Deoxyhypusine synthase (DHS) catalyzes the first step of the post-translational modification of eukaryotic translation factor 5A (eIF5A), which is the only known protein containing the amino acid hypusine. Both proteins are essential for eukaryotic cell viability, and DHS has been suggested as a good candidate target for small molecule-based therapies against eukaryotic pathogens. In this work, we focused on the DHS enzymes from Brugia malayi and Leishmania major, the causative agents of lymphatic filariasis and cutaneous leishmaniasis, respectively. To enable B. malayi (Bm)DHS for future target-based drug discovery programs, we determined its crystal structure bound to cofactor NAD+. We also reported an in vitro biochemical assay for this enzyme that is amenable to a high-throughput screening format. The L. major genome encodes two DHS paralogs, and attempts to produce them recombinantly in bacterial cells were not successful. Nevertheless, we showed that ectopic expression of both LmDHS paralogs can rescue yeast cells lacking the endogenous DHS-encoding gene (dys1). Thus, functionally complemented dys1Δ yeast mutants can be used to screen for new inhibitors of the L. major enzyme. We used the known human DHS inhibitor GC7 to validate both in vitro and yeast-based DHS assays. Our results show that BmDHS is a homotetrameric enzyme that shares many features with its human homologue, whereas LmDHS paralogs are likely to form a heterotetrameric complex and have a distinct regulatory mechanism. We expect our work to facilitate the identification and development of new DHS inhibitors that can be used to validate these enzymes as vulnerable targets for therapeutic interventions against B. malayi and L. major infections. Target-based drug discovery strategies hold the promise to discover safer and more effective treatments for Neglected Tropical Diseases (NTDs). Genetic manipulation techniques have been used to successfully identify essential genes in eukaryotic parasites. Unfortunately, the fact that a gene is essential under controlled laboratory conditions does not automatically make the corresponding gene-product vulnerable to pharmacological intervention in a clinical setting within the human host. To allow the discovery and development of small molecule tool compounds that can be used to validate pharmacologically vulnerable targets, one must first establish compound screening assays and obtain structural information for the candidate target. Eukaryotic cells lacking deoxyhypusine synthase (DHS) function are not viable. DHS catalyzes the first step in a post-translational modification that is critical for the function of eIF5A. Presence of mature eIF5A is also essential for eukaryotic cell viability. Here we reported compound screening assays (yeast-based for Brugia malayi and Leishmania major; in vitro for B. malayi only) and provided further regulatory and structural insights we hope will aid in the identification and development of inhibitors for the DHS enzymes from two NTD-causing organisms—B. malayi, the causative agent of lymphatic filariasis and L. major, the causative agent of cutaneous leishmaniasis.
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Affiliation(s)
| | | | - Priscila Zonzini Ramos
- Molecular Biology and Genetic Engineering Center (CBMEG), Medicinal Chemistry Center (CQMED), Structural Genomics Consortium (SGC-UNICAMP), University of Campinas-UNICAMP, Campinas, SP, Brazil
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas—UNICAMP, Campinas, SP, Brazil
| | - André da Silva Santiago
- Molecular Biology and Genetic Engineering Center (CBMEG), Medicinal Chemistry Center (CQMED), Structural Genomics Consortium (SGC-UNICAMP), University of Campinas-UNICAMP, Campinas, SP, Brazil
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas—UNICAMP, Campinas, SP, Brazil
| | | | - Mario Henrique Bengtson
- Molecular Biology and Genetic Engineering Center (CBMEG), Medicinal Chemistry Center (CQMED), Structural Genomics Consortium (SGC-UNICAMP), University of Campinas-UNICAMP, Campinas, SP, Brazil
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas—UNICAMP, Campinas, SP, Brazil
| | - Katlin Brauer Massirer
- Molecular Biology and Genetic Engineering Center (CBMEG), Medicinal Chemistry Center (CQMED), Structural Genomics Consortium (SGC-UNICAMP), University of Campinas-UNICAMP, Campinas, SP, Brazil
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas—UNICAMP, Campinas, SP, Brazil
| | - Elizabeth Bilsland
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas—UNICAMP, Campinas, SP, Brazil
| | - Rafael Miguez Couñago
- Molecular Biology and Genetic Engineering Center (CBMEG), Medicinal Chemistry Center (CQMED), Structural Genomics Consortium (SGC-UNICAMP), University of Campinas-UNICAMP, Campinas, SP, Brazil
- * E-mail: (RMC); (CFZ)
| | - Cleslei Fernando Zanelli
- School of Pharmaceutical Sciences, São Paulo State University—UNESP, Araraquara, SP, Brazil
- * E-mail: (RMC); (CFZ)
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13
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An Increase in Liver Polyamine Concentration Contributes to the Tryptophan-Induced Acute Stimulation of Rat Hepatic Protein Synthesis. Nutrients 2020; 12:nu12092665. [PMID: 32882842 PMCID: PMC7551729 DOI: 10.3390/nu12092665] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 01/02/2023] Open
Abstract
Tryptophan has a unique role as a nutritional signaling molecule that regulates protein synthesis in mouse and rat liver. However, the mechanism underlying the stimulating actions of tryptophan on hepatic protein synthesis remains unclear. Proteomic and metabolomic analyses were performed to identify candidate proteins and metabolites likely to play a role in the stimulation of protein synthesis by tryptophan. Overnight-fasted rats were orally administered L-tryptophan and then sacrificed 1 or 3 h after administration. Four differentially expressed protein spots were detected in rat liver at 3 h after tryptophan administration, of which one was identified as an ornithine aminotransferase (OAT) precursor. OAT is the main catabolic enzyme for ornithine, and its expression was significantly decreased by tryptophan administration. The concentration of ornithine was increased in the liver at 3 h after tryptophan administration. Ornithine is a precursor for polyamine biosynthesis. Significantly increased concentrations of polyamines were found in the liver at 3 h after administration of tryptophan. Additionally, enhanced hepatic protein synthesis was demonstrated by oral administration of putrescine. We speculate that the increase in ornithine level through suppression of OAT expression by tryptophan administration may lead to accelerated polyamine synthesis, thereby promoting protein synthesis in the liver.
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14
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Half Way to Hypusine-Structural Basis for Substrate Recognition by Human Deoxyhypusine Synthase. Biomolecules 2020; 10:biom10040522. [PMID: 32235505 PMCID: PMC7226451 DOI: 10.3390/biom10040522] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/23/2020] [Accepted: 03/26/2020] [Indexed: 02/08/2023] Open
Abstract
Deoxyhypusine synthase (DHS) is a transferase enabling the formation of deoxyhypusine, which is the first, rate-limiting step of a unique post-translational modification: hypusination. DHS catalyses the transfer of a 4-aminobutyl moiety of polyamine spermidine to a specific lysine of eukaryotic translation factor 5A (eIF5A) precursor in a nicotinamide adenine dinucleotide (NAD)-dependent manner. This modification occurs exclusively on one protein, eIF5A, and it is essential for cell proliferation. Malfunctions of the hypusination pathway, including those caused by mutations within the DHS encoding gene, are associated with conditions such as cancer or neurodegeneration. Here, we present a series of high-resolution crystal structures of human DHS. Structures were determined as the apoprotein, as well as ligand-bound states at high-resolutions ranging from 1.41 to 1.69 Å. By solving DHS in complex with its natural substrate spermidine (SPD), we identified the mode of substrate recognition. We also observed that other polyamines, namely spermine (SPM) and putrescine, bind DHS in a similar manner as SPD. Moreover, we performed activity assays showing that SPM could to some extent serve as an alternative DHS substrate. In contrast to previous studies, we demonstrate that no conformational changes occur in the DHS structure upon spermidine-binding. By combining mutagenesis and a light-scattering approach, we show that a conserved “ball-and-chain” motif is indispensable to assembling a functional DHS tetramer. Our study substantially advances our knowledge of the substrate recognition mechanism by DHS and may aid the design of pharmacological compounds for potential applications in cancer therapy.
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15
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Manjunath H, Zhang H, Rehfeld F, Han J, Chang TC, Mendell JT. Suppression of Ribosomal Pausing by eIF5A Is Necessary to Maintain the Fidelity of Start Codon Selection. Cell Rep 2019; 29:3134-3146.e6. [PMID: 31801078 PMCID: PMC6917043 DOI: 10.1016/j.celrep.2019.10.129] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/19/2019] [Accepted: 10/30/2019] [Indexed: 12/12/2022] Open
Abstract
Sequences within 5' UTRs dictate the site and efficiency of translation initiation. In this study, an unbiased screen designed to interrogate the 5' UTR-mediated regulation of the growth-promoting gene MYC unexpectedly revealed the ribosomal pause relief factor eIF5A as a regulator of translation initiation codon selection. Depletion of eIF5A enhances upstream translation within 5' UTRs across yeast and human transcriptomes, including on the MYC transcript, where this results in increased production of an N-terminally extended protein. Furthermore, ribosome profiling experiments established that the function of eIF5A as a suppressor of ribosomal pausing at sites of suboptimal peptide bond formation is conserved in human cells. We present evidence that proximal ribosomal pausing on a transcript triggers enhanced use of upstream suboptimal or non-canonical initiation codons. Thus, we propose that eIF5A functions not only to maintain efficient translation elongation in eukaryotic cells but also to maintain the fidelity of translation initiation.
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Affiliation(s)
- Hema Manjunath
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - He Zhang
- Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390-8821, USA; Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390-8821, USA
| | - Frederick Rehfeld
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Jaeil Han
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Tsung-Cheng Chang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Joshua T Mendell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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16
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Ribosome collisions alter frameshifting at translational reprogramming motifs in bacterial mRNAs. Proc Natl Acad Sci U S A 2019; 116:21769-21779. [PMID: 31591196 PMCID: PMC6815119 DOI: 10.1073/pnas.1910613116] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ribosomes move along mRNAs in 3-nucleotide steps as they interpret codons that specify which amino acid is required at each position in the protein. There are multiple examples of genes with DNA sequences that do not match the produced proteins because ribosomes move to a new reading frame in the message before finishing translation (so-called frameshifting). This report shows that, when ribosomes stall at mRNA regions prone to cause frameshifting events, trailing ribosomes that collide with them can significantly change the outcome and potentially regulate protein production. This work highlights the principle that biological macromolecules do not function in isolation, and it provides an example of how physical interactions between neighboring complexes can be used to augment their performance. Translational frameshifting involves the repositioning of ribosomes on their messages into decoding frames that differ from those dictated during initiation. Some messenger RNAs (mRNAs) contain motifs that promote deliberate frameshifting to regulate production of the encoded proteins. The mechanisms of frameshifting have been investigated in many systems, and the resulting models generally involve single ribosomes responding to stimulator sequences in their engaged mRNAs. We discovered that the abundance of ribosomes on messages containing the IS3, dnaX, and prfB frameshift motifs significantly influences the levels of frameshifting. We show that this phenomenon results from ribosome collisions that occur during translational stalling, which can alter frameshifting in both the stalled and trailing ribosomes. Bacteria missing ribosomal protein bL9 are known to exhibit a reduction in reading frame maintenance and to have a strong dependence on elongation factor P (EFP). We discovered that ribosomes lacking bL9 become compacted closer together during collisions and that the E-sites of the stalled ribosomes appear to become blocked, which suggests subsequent transpeptidation in transiently stalled ribosomes may become compromised in the absence of bL9. In addition, we determined that bL9 can suppress frameshifting of its host ribosome, likely by regulating E-site dynamics. These findings provide mechanistic insight into the behavior of colliding ribosomes during translation and suggest naturally occurring frameshift elements may be regulated by the abundance of ribosomes relative to an mRNA pool.
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17
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Aksu M, Trakhanov S, Vera Rodriguez A, Görlich D. Structural basis for the nuclear import and export functions of the biportin Pdr6/Kap122. J Cell Biol 2019; 218:1839-1852. [PMID: 31023722 PMCID: PMC6548137 DOI: 10.1083/jcb.201812093] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/26/2019] [Accepted: 03/28/2019] [Indexed: 12/26/2022] Open
Abstract
Importins ferry proteins into nuclei while exportins carry cargoes to the cytoplasm. In the accompanying paper in this issue (Vera Rodriguez et al. 2019. J. Cell Biol. https://doi.org/10.1083/jcb.201812091), we discovered that Pdr6 is a biportin that imports, e.g., the SUMO E2 ligase Ubc9 while depleting the translation factor eIF5A from the nuclear compartment. In this paper, we report the structures of key transport intermediates, namely, of the Ubc9•Pdr6 import complex, of the RanGTP•Pdr6 heterodimer, and of the trimeric RanGTP•Pdr6•eIF5A export complex. These revealed nonlinear transport signals, chaperone-like interactions, and how the RanGTPase system drives Pdr6 to transport Ubc9 and eIF5A in opposite directions. The structures also provide unexpected insights into the evolution of transport selectivity. Specifically, they show that recognition of Ubc9 by Pdr6 differs fundamentally from that of the human Ubc9-importer Importin 13. Likewise, Pdr6 recognizes eIF5A in a nonhomologous manner compared with the mammalian eIF5A-exporter Exportin 4. This suggests that the import of Ubc9 and active nuclear exclusion of eIF5A evolved in different eukaryotic lineages more than once and independently from each other.
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Affiliation(s)
- Metin Aksu
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sergei Trakhanov
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Arturo Vera Rodriguez
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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18
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Abstract
Polyamines are organic polycations that bind to a variety of cellular molecules, including nucleic acids. Within cells, polyamines contribute to both the efficiency and fidelity of protein synthesis. In addition to directly acting on the translation apparatus to stimulate protein synthesis, the polyamine spermidine serves as a precursor for the essential post-translational modification of the eukaryotic translation factor 5A (eIF5A), which is required for synthesis of proteins containing problematic amino acid sequence motifs, including polyproline tracts, and for termination of translation. The impact of polyamines on translation is highlighted by autoregulation of the translation of mRNAs encoding key metabolic and regulatory proteins in the polyamine biosynthesis pathway, including S-adenosylmethionine decarboxylase (AdoMetDC), antizyme (OAZ), and antizyme inhibitor 1 (AZIN1). Here, we highlight the roles of polyamines in general translation and also in the translational regulation of polyamine biosynthesis.
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Affiliation(s)
- Thomas E Dever
- From the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Ivaylo P Ivanov
- From the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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19
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Park MH, Wolff EC. Hypusine, a polyamine-derived amino acid critical for eukaryotic translation. J Biol Chem 2018; 293:18710-18718. [PMID: 30257869 DOI: 10.1074/jbc.tm118.003341] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The natural amino acid hypusine (N ϵ-4-amino-2-hydroxybutyl(lysine)) is derived from the polyamine spermidine, and occurs only in a single family of cellular proteins, eukaryotic translation factor 5A (eIF5A) isoforms. Hypusine is formed by conjugation of the aminobutyl moiety of spermidine to a specific lysine residue of this protein. The posttranslational synthesis of hypusine involves two enzymatic steps, catalyzed by deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). Hypusine is essential for eIF5A activity. Inactivation of either the eIF5A or the DHPS gene is lethal in yeast and mouse, underscoring the vital role of eIF5A hypusination in eukaryotic cell growth and animal development. The long and basic side chain of the hypusine residue promotes eIF5A-mediated translation elongation by facilitating peptide bond formation at polyproline stretches and at many other ribosome-pausing sites. It also enhances translation termination by stimulating peptide release. By promoting translation, the hypusine modification of eIF5A provides a key link between polyamines and cell growth regulation. eIF5A has been implicated in several human pathological conditions. Recent genetic data suggest that eIF5A haploinsufficiency or impaired deoxyhypusine synthase activity is associated with neurodevelopmental disorders in humans.
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Affiliation(s)
- Myung Hee Park
- From the NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Edith C Wolff
- From the NIDCR, National Institutes of Health, Bethesda, Maryland 20892
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20
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Abstract
During protein synthesis, ribosomes encounter many roadblocks, the outcomes of which are largely determined by substrate availability, amino acid features and reaction kinetics. Prolonged ribosome stalling is likely to be resolved by ribosome rescue or quality control pathways, whereas shorter stalling is likely to be resolved by ongoing productive translation. How ribosome function is affected by such hindrances can therefore have a profound impact on the translational output (yield) of a particular mRNA. In this Review, we focus on these roadblocks and the resumption of normal translation elongation rather than on alternative fates wherein the stalled ribosome triggers degradation of the mRNA and the incomplete protein product. We discuss the fundamental stages of the translation process in eukaryotes, from elongation through ribosome recycling, with particular attention to recent discoveries of the complexity of the genetic code and regulatory elements that control gene expression, including ribosome stalling during elongation, the role of mRNA context in translation termination and mechanisms of ribosome rescue that resemble recycling.
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Affiliation(s)
- Anthony P Schuller
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rachel Green
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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21
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Hummels KR, Witzky A, Rajkovic A, Tollerson R, Jones LA, Ibba M, Kearns DB. Carbonyl reduction by YmfI in Bacillus subtilis prevents accumulation of an inhibitory EF-P modification state. Mol Microbiol 2017; 106:236-251. [PMID: 28787546 DOI: 10.1111/mmi.13760] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2017] [Indexed: 12/29/2022]
Abstract
Translation elongation factor P (EF-P) in Bacillus subtilis is required for a form of surface migration called swarming motility. Furthermore, B. subtilis EF-P is post-translationally modified with a 5-aminopentanol group but the pathway necessary for the synthesis and ligation of the modification is unknown. Here we determine that the protein YmfI catalyzes the reduction of EF-P-5 aminopentanone to EF-P-5 aminopentanol. In the absence of YmfI, accumulation of 5-aminopentanonated EF-P is inhibitory to swarming motility. Suppressor mutations that enhanced swarming in the absence of YmfI were found at two positions on EF-P, including one that changed the conserved modification site (Lys 32) and abolished post-translational modification. Thus, while modification of EF-P is thought to be essential for EF-P activity, here we show that in some cases it can be dispensable. YmfI is the first protein identified in the pathway leading to EF-P modification in B. subtilis, and B. subtilis encodes the first EF-P ortholog that retains function in the absence of modification.
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Affiliation(s)
| | - Anne Witzky
- Department of Molecular Genetics and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Andrei Rajkovic
- Department of Microbiology and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Rodney Tollerson
- Department of Microbiology and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Lisa A Jones
- Proteomics Facility, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Michael Ibba
- Department of Microbiology and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Daniel B Kearns
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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22
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Shin BS, Katoh T, Gutierrez E, Kim JR, Suga H, Dever TE. Amino acid substrates impose polyamine, eIF5A, or hypusine requirement for peptide synthesis. Nucleic Acids Res 2017; 45:8392-8402. [PMID: 28637321 PMCID: PMC5737446 DOI: 10.1093/nar/gkx532] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/05/2017] [Accepted: 06/08/2017] [Indexed: 01/20/2023] Open
Abstract
Whereas ribosomes efficiently catalyze peptide bond synthesis by most amino acids, the imino acid proline is a poor substrate for protein synthesis. Previous studies have shown that the translation factor eIF5A and its bacterial ortholog EF-P bind in the E site of the ribosome where they contact the peptidyl-tRNA in the P site and play a critical role in promoting the synthesis of polyproline peptides. Using misacylated Pro-tRNAPhe and Phe-tRNAPro, we show that the imino acid proline and not tRNAPro imposes the primary eIF5A requirement for polyproline synthesis. Though most proline analogs require eIF5A for efficient peptide synthesis, azetidine-2-caboxylic acid, a more flexible four-membered ring derivative of proline, shows relaxed eIF5A dependency, indicating that the structural rigidity of proline might contribute to the requirement for eIF5A. Finally, we examine the interplay between eIF5A and polyamines in promoting translation elongation. We show that eIF5A can obviate the polyamine requirement for general translation elongation, and that this activity is independent of the conserved hypusine modification on eIF5A. Thus, we propose that the body of eIF5A functionally substitutes for polyamines to promote general protein synthesis and that the hypusine modification on eIF5A is critically important for poor substrates like proline.
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Affiliation(s)
- Byung-Sik Shin
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Takayuki Katoh
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Erik Gutierrez
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joo-Ran Kim
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Thomas E. Dever
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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23
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Hobley L, Li B, Wood JL, Kim SH, Naidoo J, Ferreira AS, Khomutov M, Khomutov A, Stanley-Wall NR, Michael AJ. Spermidine promotes Bacillus subtilis biofilm formation by activating expression of the matrix regulator slrR. J Biol Chem 2017; 292:12041-12053. [PMID: 28546427 PMCID: PMC5519356 DOI: 10.1074/jbc.m117.789644] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/23/2017] [Indexed: 11/16/2022] Open
Abstract
Ubiquitous polyamine spermidine is not required for normal planktonic growth of Bacillus subtilis but is essential for robust biofilm formation. However, the structural features of spermidine required for B. subtilis biofilm formation are unknown and so are the molecular mechanisms of spermidine-stimulated biofilm development. We report here that in a spermidine-deficient B. subtilis mutant, the structural analogue norspermidine, but not homospermidine, restored biofilm formation. Intracellular biosynthesis of another spermidine analogue, aminopropylcadaverine, from exogenously supplied homoagmatine also restored biofilm formation. The differential ability of C-methylated spermidine analogues to functionally replace spermidine in biofilm formation indicated that the aminopropyl moiety of spermidine is more sensitive to C-methylation, which it is essential for biofilm formation, but that the length and symmetry of the molecule is not critical. Transcriptomic analysis of a spermidine-depleted B. subtilis speD mutant uncovered a nitrogen-, methionine-, and S-adenosylmethionine-sufficiency response, resulting in repression of gene expression related to purine catabolism, methionine and S-adenosylmethionine biosynthesis and methionine salvage, and signs of altered membrane status. Consistent with the spermidine requirement in biofilm formation, single-cell analysis of this mutant indicated reduced expression of the operons for production of the exopolysaccharide and TasA protein biofilm matrix components and SinR antagonist slrR. Deletion of sinR or ectopic expression of slrR in the spermidine-deficient ΔspeD background restored biofilm formation, indicating that spermidine is required for expression of the biofilm regulator slrR. Our results indicate that spermidine functions in biofilm development by activating transcription of the biofilm matrix exopolysaccharide and TasA operons through the regulator slrR.
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Affiliation(s)
- Laura Hobley
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390; Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD15EH, Scotland, United Kingdom
| | - Bin Li
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390; Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Jennifer L Wood
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD15EH, Scotland, United Kingdom
| | - Sok Ho Kim
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Jacinth Naidoo
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Ana Sofia Ferreira
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD15EH, Scotland, United Kingdom
| | - Maxim Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Alexey Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Nicola R Stanley-Wall
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD15EH, Scotland, United Kingdom.
| | - Anthony J Michael
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390; Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390.
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24
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Barbosa NM, Boldrin PEG, Rossi D, Yamamoto PA, Watanabe TF, Serrão VH, Hershey JWB, Fraser CS, Valentini SR, Zanelli CF. Mapping surface residues of eIF5A that are important for binding to the ribosome using alanine scanning mutagenesis. Amino Acids 2016; 48:2363-74. [PMID: 27388480 PMCID: PMC5897047 DOI: 10.1007/s00726-016-2279-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/11/2016] [Indexed: 01/15/2023]
Abstract
The translation elongation factor eIF5A is conserved through evolution and is necessary to rescue the ribosome during translation elongation of polyproline-containing proteins. Although the site of eIF5A binding to the ribosome is known, no systematic analysis has been performed so far to determine the important residues on the surface of eIF5A required for ribosome binding. In this study, we used clustered charged-to-alanine mutagenesis and structural modeling to address this question. We generated four new mutants of yeast eIF5A: tif51A-4, tif51A-6, tif51A-7 and tif51A-11, and complementation analysis revealed that tif51A-4 and tif51A-7 could not sustain cell growth in a strain lacking wild-type eIF5A. Moreover, the allele tif51A-4 also displayed negative dominance over wild-type eIF5A. Both in vivo GST-pulldowns and in vitro fluorescence anisotropy demonstrated that eIF5A from mutant tif51A-7 exhibited an importantly reduced affinity for the ribosome, implicating the charged residues in cluster 7 as determinant features on the eIF5A surface for contacting the ribosome. Notably, modified eIF5A from mutant tif51A-4, despite exhibiting the most severe growth phenotype, did not abolish ribosome interactions as with mutant tif51A-7. Taking into account the modeling eIF5A + 80S + P-tRNA complex, our data suggest that interactions of eIF5A with ribosomal protein L1 are more important to stabilize the interaction with the ribosome as a whole than the contacts with P-tRNA. Finally, the ability of eIF5A from tif51A-4 to bind to the ribosome while potentially blocking physical interaction with P-tRNA could explain its dominant negative phenotype.
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Affiliation(s)
- Natália M Barbosa
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University-UNESP, Rod Araraquara-Jaú Km01, Araraquara, SP, 14800-903, Brazil
| | - Paulo E G Boldrin
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University-UNESP, Rod Araraquara-Jaú Km01, Araraquara, SP, 14800-903, Brazil
| | - Danuza Rossi
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University-UNESP, Rod Araraquara-Jaú Km01, Araraquara, SP, 14800-903, Brazil
| | - Priscila A Yamamoto
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University-UNESP, Rod Araraquara-Jaú Km01, Araraquara, SP, 14800-903, Brazil
| | - Tatiana F Watanabe
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University-UNESP, Rod Araraquara-Jaú Km01, Araraquara, SP, 14800-903, Brazil
| | - Vitor H Serrão
- Physics and Interdisciplinary Science Department, Physics Institute of Sao Carlos, University of Sao Paulo-USP, Sao Carlos, SP, 13563-120, Brazil
| | - John W B Hershey
- Molecular and Cellular Biology Department, University of California, Davis, CA, 95616, USA
| | - Christopher S Fraser
- Molecular and Cellular Biology Department, University of California, Davis, CA, 95616, USA
| | - Sandro R Valentini
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University-UNESP, Rod Araraquara-Jaú Km01, Araraquara, SP, 14800-903, Brazil
| | - Cleslei F Zanelli
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University-UNESP, Rod Araraquara-Jaú Km01, Araraquara, SP, 14800-903, Brazil.
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25
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Aksu M, Trakhanov S, Görlich D. Structure of the exportin Xpo4 in complex with RanGTP and the hypusine-containing translation factor eIF5A. Nat Commun 2016; 7:11952. [PMID: 27306458 PMCID: PMC4912631 DOI: 10.1038/ncomms11952] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 05/16/2016] [Indexed: 12/28/2022] Open
Abstract
Xpo4 is a bidirectional nuclear transport receptor that mediates nuclear export of eIF5A and Smad3 as well as import of Sox2 and SRY. How Xpo4 recognizes such a variety of cargoes is as yet unknown. Here we present the crystal structure of the RanGTP·Xpo4·eIF5A export complex at 3.2 Å resolution. Xpo4 has a similar structure as CRM1, but the NES-binding site is occluded, and a new interaction site evolved that recognizes both globular domains of eIF5A. eIF5A contains hypusine, a unique amino acid with two positive charges, which is essential for cell viability and eIF5A function in translation. The hypusine docks into a deep, acidic pocket of Xpo4 and is thus a critical element of eIF5A's complex export signature. This further suggests that Xpo4 recognizes other cargoes differently, and illustrates how Xpo4 suppresses - in a chaperone-like manner - undesired interactions of eIF5A inside nuclei.
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Affiliation(s)
- Metin Aksu
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Sergei Trakhanov
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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26
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Rossi D, Barbosa NM, Galvão FC, Boldrin PEG, Hershey JWB, Zanelli CF, Fraser CS, Valentini SR. Evidence for a Negative Cooperativity between eIF5A and eEF2 on Binding to the Ribosome. PLoS One 2016; 11:e0154205. [PMID: 27115996 PMCID: PMC4845985 DOI: 10.1371/journal.pone.0154205] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/10/2016] [Indexed: 01/04/2023] Open
Abstract
eIF5A is the only protein known to contain the essential and unique amino acid residue hypusine. eIF5A functions in both translation initiation due to its stimulation of methionyl-puromycin synthesis and translation elongation, being highly required for peptide-bound formation of specific ribosome stalling sequences such as poly-proline. The functional interaction between eIF5A, tRNA, and eEF2 on the surface of the ribosome is further clarified herein. Fluorescence anisotropy assays were performed to determine the affinity of eIF5A to different ribosomal complexes and reveal its interaction exclusively and directly with the 60S ribosomal subunit in a hypusine-dependent manner (Ki60S-eIF5A-Hyp = 16 nM, Ki60S-eIF5A-Lys = 385 nM). A 3-fold increase in eIF5A affinity to the 80S is observed upon charged-tRNAiMet binding, indicating positive cooperativity between P-site tRNA binding and eIF5A binding to the ribosome. Previously identified conditional mutants of yeast eIF5A, eIF5AQ22H/L93F and eIF5AK56A, display a significant decrease in ribosome binding affinity. Binding affinity between ribosome and eIF5A-wild type or mutants eIF5AK56A, but not eIF5AQ22H/L93F, is impaired in the presence of eEF2 by 4-fold, consistent with negative cooperativity between eEF2 and eIF5A binding to the ribosome. Interestingly, high-copy eEF2 is toxic only to eIF5AQ22H/L93F and causes translation elongation defects in this mutant. These results suggest that binding of eEF2 to the ribosome alters its conformation, resulting in a weakened affinity of eIF5A and impairment of this interplay compromises cell growth due to translation elongation defects.
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Affiliation(s)
- Danuza Rossi
- School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Department of Biological Sciences, Araraquara, SP, Brazil, 14801
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA, United States of America, 95616
| | - Natalia M. Barbosa
- School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Department of Biological Sciences, Araraquara, SP, Brazil, 14801
| | - Fabio C. Galvão
- School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Department of Biological Sciences, Araraquara, SP, Brazil, 14801
| | - Paulo E. G. Boldrin
- School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Department of Biological Sciences, Araraquara, SP, Brazil, 14801
| | - John W. B. Hershey
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA, United States of America, 95616
| | - Cleslei F. Zanelli
- School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Department of Biological Sciences, Araraquara, SP, Brazil, 14801
| | - Christopher S. Fraser
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA, United States of America, 95616
| | - Sandro R. Valentini
- School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Department of Biological Sciences, Araraquara, SP, Brazil, 14801
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27
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Martinez-Rocha AL, Woriedh M, Chemnitz J, Willingmann P, Kröger C, Hadeler B, Hauber J, Schäfer W. Posttranslational hypusination of the eukaryotic translation initiation factor-5A regulates Fusarium graminearum virulence. Sci Rep 2016; 6:24698. [PMID: 27098988 PMCID: PMC4838825 DOI: 10.1038/srep24698] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 04/04/2016] [Indexed: 11/14/2022] Open
Abstract
Activation of eukaryotic translation initiation factor eIF5A requires a posttranslational modification, forming the unique amino acid hypusine. This activation is mediated by two enzymes, deoxyhypusine synthase, DHS, and deoxyhypusine hydroxylase, DOHH. The impact of this enzymatic complex on the life cycle of a fungal pathogen is unknown. Plant pathogenic ascomycetes possess a single copy of the eIF5A activated by hypusination. We evaluated the importance of imbalances in eIF5A hypusination in Fusarium graminearum, a devastating fungal pathogen of cereals. Overexpression of DHS leads to increased virulence in wheat, elevated production of the mycotoxin deoxynivalenol, more infection structures, faster wheat tissue invasion in plants and increases vegetatively produced conidia. In contrast, overexpression of DOHH completely prevents infection structure formation, pathogenicity in wheat and maize, leads to overproduction of ROS, reduced DON production and increased sexual reproduction. Simultaneous overexpression of both genes restores wild type-like phenotypes. Analysis of eIF5A posttranslational modification displayed strongly increased hypusinated eIF5A in DOHH overexpression mutant in comparison to wild type, and the DHS overexpression mutants. These are the first results pointing to different functions of differently modified eIF5A.
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Affiliation(s)
- Ana Lilia Martinez-Rocha
- University of Hamburg, Biocenter Klein Flottbek, Molecular Phytopathology and Genetics, Hamburg, D-22609, Germany
| | - Mayada Woriedh
- University of Hamburg, Biocenter Klein Flottbek, Molecular Phytopathology and Genetics, Hamburg, D-22609, Germany
| | - Jan Chemnitz
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Department Antiviral Strategies, Hamburg, D-20251, Germany
| | - Peter Willingmann
- University of Hamburg, Biocenter Klein Flottbek, Molecular Phytopathology and Genetics, Hamburg, D-22609, Germany
| | - Cathrin Kröger
- University of Hamburg, Biocenter Klein Flottbek, Molecular Phytopathology and Genetics, Hamburg, D-22609, Germany
| | - Birgit Hadeler
- University of Hamburg, Biocenter Klein Flottbek, Molecular Phytopathology and Genetics, Hamburg, D-22609, Germany
| | - Joachim Hauber
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Department Antiviral Strategies, Hamburg, D-20251, Germany
- German Center for Infection Research (DZIF), partner site Hamburg, Hamburg, Germany
| | - Wilhelm Schäfer
- University of Hamburg, Biocenter Klein Flottbek, Molecular Phytopathology and Genetics, Hamburg, D-22609, Germany
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28
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Yang Q, Ye Z, Zhang Q, Zhao Z, Yuan H. Expression of eukaryotic translation initiation factor 5A-2 (eIF5A-2) associated with poor survival in gastric cancer. Tumour Biol 2016; 37:1189-95. [PMID: 26282002 DOI: 10.1007/s13277-015-3894-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 08/05/2015] [Indexed: 02/08/2023] Open
Abstract
Altered expression of eukaryotic translation initiation factor 5A-2 (eIF5A-2) was associated with human carcinogenesis and progression. This study assessed eIF5A-2 expression in gastric cancer tissues for association with clinicopathological parameters and survival of patients. A total of 436 gastric cancer tissues and 92 normal mucosal blocks were collected for construction of tissue microarrays and immunohistochemical assessment of eIF5A-2 expression. The data were statistically analyzed for association with clinicopathological factors and survival of patients. Immunohistochemical data showed that eIF5A-2 protein was highly expressed in gastric cancer tissues (p < 0.001). Upregulated expression of eIF5A-2 protein was associated with tumor Lauren classification, size, location, invasion, TNM stages, and lymph node and distant metastases. The 3- and 5-year cumulative survival rates of these 436 patients were 88.5 and 58.1 %, respectively. In contrast, the mean survival time of patients with increased tumor eIF5A-2 was 30.22 ± 1.23 vs. 51.29 ± 0.86 months for those with low tumor eIF5A-2 (p < 0.001). Multivariate analysis showed that eIF5A-2 expression and related tumor parameters were independent indicators of overall survival in gastric cancer patients. In conclusion, the current study indicates that overexpression of eIF5A-2 protein was associated with poor overall survival of gastric cancer patients.
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Affiliation(s)
- Qiong Yang
- Wenzhou Medical University, Wenzhou, China
- Department of Gastrointestinal Surgery, Zhejiang Provincial People's Hospital, Hangzhou, China
| | - Zaiyuan Ye
- Wenzhou Medical University, Wenzhou, China.
- Department of Gastrointestinal Surgery, Zhejiang Provincial People's Hospital, Hangzhou, China.
| | - Qi Zhang
- Department of Gastrointestinal Surgery, Zhejiang Provincial People's Hospital, Hangzhou, China
| | - Zhongsheng Zhao
- Department of Gastrointestinal Surgery, Zhejiang Provincial People's Hospital, Hangzhou, China.
| | - Hongjun Yuan
- Department of Gastrointestinal Surgery, Zhejiang Provincial People's Hospital, Hangzhou, China
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29
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Seko Y, Fujimura T, Yao T, Taka H, Mineki R, Okumura K, Murayama K. Secreted tyrosine sulfated-eIF5A mediates oxidative stress-induced apoptosis. Sci Rep 2015; 5:13737. [PMID: 26348594 PMCID: PMC4562266 DOI: 10.1038/srep13737] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 08/04/2015] [Indexed: 11/11/2022] Open
Abstract
Oxidative stress plays a critical role in ischemia/reperfusion-injury, atherosclerosis, and aging. It causes cell damage that leads to apoptosis via uncertain mechanisms. Because conditioned medium from cardiac myocytes subjected to hypoxia/reoxygenation induces extensive apoptosis of cardiac myocytes under normoxia, we hypothesized that a humoral factor released from the hypoxic/reoxygenated cardiac myocytes mediates apoptosis. We identified an apoptosis-inducing humoral factor in the hypoxia/reoxygenation-conditioned medium. Here, we found that eIF5A undergoes tyrosine sulfation in the trans-Golgi and is rapidly secreted from cardiac myocytes in response to hypoxia/reoxygenation; then, eIF5A induces apoptosis by acting as a pro-apoptotic ligand. The apoptosis of cardiac myocytes induced by hypoxia/reoxygenation or ultraviolet irradiation was suppressed by anti-eIF5A neutralizing monoclonal antibodies (mAbs) in vitro. Myocardial ischemia/reperfusion (but not ischemia alone) markedly increased the plasma levels of eIF5A, and treatment with anti-eIF5A neutralizing mAbs significantly reduced myocardial injury. These results identify an important, novel specific biomarker and a critical therapeutic target for oxidative stress-induced cell injury.
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Affiliation(s)
- Yoshinori Seko
- Department of Cardiovascular Medicine, The Institute for Adult Diseases, Asahi Life Foundation, 2-2-6 Nihonbashi-Bakurocho, Chuo-ku, Tokyo 103-0002, Japan
- Department of Immunology, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Tsutomu Fujimura
- Division of Proteomics and Biomolecular Science, BioMedical Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Takako Yao
- Department of Cardiovascular Medicine, The Institute for Adult Diseases, Asahi Life Foundation, 2-2-6 Nihonbashi-Bakurocho, Chuo-ku, Tokyo 103-0002, Japan
| | - Hikari Taka
- Division of Proteomics and Biomolecular Science, BioMedical Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Reiko Mineki
- Division of Proteomics and Biomolecular Science, BioMedical Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Ko Okumura
- Department of Immunology, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Kimie Murayama
- Division of Proteomics and Biomolecular Science, BioMedical Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
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30
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Nguyen S, Leija C, Kinch L, Regmi S, Li Q, Grishin NV, Phillips MA. Deoxyhypusine Modification of Eukaryotic Translation Initiation Factor 5A (eIF5A) Is Essential for Trypanosoma brucei Growth and for Expression of Polyprolyl-containing Proteins. J Biol Chem 2015; 290:19987-98. [PMID: 26082486 PMCID: PMC4528157 DOI: 10.1074/jbc.m115.656785] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 05/18/2015] [Indexed: 11/06/2022] Open
Abstract
The eukaryotic protozoan parasite Trypanosoma brucei is the causative agent of human African trypanosomiasis. Polyamine biosynthesis is essential in T. brucei, and the polyamine spermidine is required for synthesis of a novel cofactor called trypanothione and for deoxyhypusine modification of eukaryotic translation initiation factor 5A (eIF5A). eIF5A promotes translation of proteins containing polyprolyl tracts in mammals and yeast. To evaluate the function of eIF5A in T. brucei, we used RNA interference (RNAi) to knock down eIF5A levels and found that it is essential for T. brucei growth. The RNAi-induced growth defect was complemented by expression of wild-type human eIF5A but not by a Lys-50 mutant that blocks modification by deoxyhypusine. Bioinformatics analysis showed that 15% of the T. brucei proteome contains 3 or more consecutive prolines and that actin-related proteins and cysteine proteases were highly enriched in the group. Steady-state protein levels of representative proteins containing 9 consecutive prolines that are involved in actin assembly (formin and CAP/Srv2p) were significantly reduced by knockdown of eIF5A. Several T. brucei polyprolyl proteins are involved in flagellar assembly. Knockdown of TbeIF5A led to abnormal cell morphologies and detached flagella, suggesting that eIF5A is important for translation of proteins needed for these processes. Potential specialized functions for eIF5A in T. brucei in translation of variable surface glycoproteins were also uncovered. Inhibitors of deoxyhypusination would be expected to cause a pleomorphic effect on multiple cell processes, suggesting that deoxyhypusine/hypusine biosynthesis could be a promising drug target in not just T. brucei but in other eukaryotic pathogens.
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MESH Headings
- Amino Acid Sequence
- Animals
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Flagella/genetics
- Flagella/metabolism
- Flagella/ultrastructure
- Gene Knockdown Techniques
- Humans
- Lysine/analogs & derivatives
- Lysine/metabolism
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Molecular Sequence Data
- Peptide Initiation Factors/antagonists & inhibitors
- Peptide Initiation Factors/genetics
- Peptide Initiation Factors/metabolism
- Peptides/metabolism
- Protein Processing, Post-Translational
- Proteome/genetics
- Proteome/metabolism
- Protozoan Proteins/antagonists & inhibitors
- Protozoan Proteins/genetics
- Protozoan Proteins/metabolism
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Protozoan/antagonists & inhibitors
- RNA, Protozoan/genetics
- RNA, Protozoan/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- RNA-Binding Proteins/antagonists & inhibitors
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sequence Alignment
- Sequence Homology, Amino Acid
- Trypanosoma brucei brucei/genetics
- Trypanosoma brucei brucei/metabolism
- Trypanosoma brucei brucei/ultrastructure
- Eukaryotic Translation Initiation Factor 5A
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Affiliation(s)
| | | | | | | | - Qiong Li
- From the Departments of Pharmacology and
| | - Nick V Grishin
- Biophysics and Biochemistry and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041
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31
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Mathews MB, Hershey JWB. The translation factor eIF5A and human cancer. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1849:836-44. [PMID: 25979826 PMCID: PMC4732523 DOI: 10.1016/j.bbagrm.2015.05.002] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 05/06/2015] [Indexed: 12/14/2022]
Abstract
The eukaryotic initiation factor eIF5A is a translation factor that, unusually, has been assigned functions in both initiation and elongation. Additionally, it is implicated in transcription, mRNA turnover and nucleocytoplasmic transport. Two eIF5A isoforms are generated from distinct but related genes. The major isoform, eIF5A1, is considered constitutive, is abundantly expressed in most cells, and is essential for cell proliferation. The second isoform, eIF5A2, is expressed in few normal tissues but is highly expressed in many cancers and has been designated a candidate oncogene. Elevated expression of either isoform carries unfavorable prognostic implications for several cancers, and both have been advanced as cancer biomarkers. The amino acid hypusine, a presumptively unique eIF5A post-translational modification, is required for most known eIF5A functions and it renders eIF5A susceptible to inhibitors of the modification pathway as therapeutic targets. eIF5A has been shown to regulate a number of gene products specifically, termed the eIF5A regulon, and its role in translating proline-rich sequences has recently been identified. A model is advanced that accommodates eIF5A in both the initiation and elongation phases of translation. We review here the biochemical functions of eIF5A, the relationship of its isoforms with human cancer, and evolving clinical applications. This article is part of a Special Issue entitled: Translation and Cancer.
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Affiliation(s)
- Michael B Mathews
- Department of Medicine, Rutgers New Jersey Medical School, Newark, NJ 07103, USA.
| | - John W B Hershey
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Davis, CA 95616, USA.
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32
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Fujimura K, Wright T, Strnadel J, Kaushal S, Metildi C, Lowy AM, Bouvet M, Kelber JA, Klemke RL. A hypusine-eIF5A-PEAK1 switch regulates the pathogenesis of pancreatic cancer. Cancer Res 2014; 74:6671-81. [PMID: 25261239 PMCID: PMC4233190 DOI: 10.1158/0008-5472.can-14-1031] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Deregulation of protein synthesis is a hallmark of cancer cell proliferation, survival, and metastatic progression. eIF5A1 and its highly related isoform eIF5A2 are translation initiation factors that have been implicated in a range of human malignancies, but how they control cancer development and disease progression is still poorly understood. Here, we investigated how eIF5A proteins regulate pancreatic ductal adenocarcinoma (PDAC) pathogenesis. eIF5A proteins are the only known proteins regulated by a distinct posttranslational modification termed hypusination, which is catalyzed by two enzymes, deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). The highly selective nature of the hypusine modification and its amenability to pharmacologic inhibition make eIF5A proteins attractive therapeutic targets. We found that the expression and hypusination of eIF5A proteins are upregulated in human PDAC tissues and in premalignant pancreatic intraepithelial neoplasia tissues isolated from Pdx-1-Cre: LSL-KRAS(G12D) mice. Knockdown of eIF5A proteins in PDAC cells inhibited their growth in vitro and orthotopic tumor growth in vivo, whereas amplification of eIF5A proteins increased PDAC cell growth and tumor formation in mice. Small-molecule inhibitors of DHPS and DOHH both suppressed eIF5A hypusination, preventing PDAC cell growth. Interestingly, we found that eIF5A proteins regulate PDAC cell growth by modulating the expression of PEAK1, a nonreceptor tyrosine kinase essential for PDAC cell growth and therapy resistance. Our findings suggest that eIF5A proteins utilize PEAK1 as a downstream effector to drive PDAC pathogenesis and that pharmacologic inhibition of the eIF5A-hypusine-PEAK1 axis may provide a novel therapeutic strategy to combat this deadly disease.
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Affiliation(s)
- Ken Fujimura
- Department of Pathology, University of California, San Diego, La Jolla, California. Moores Cancer Center, University of California, San Diego, La Jolla, California
| | - Tracy Wright
- Department of Pathology, University of California, San Diego, La Jolla, California. Moores Cancer Center, University of California, San Diego, La Jolla, California
| | - Jan Strnadel
- Department of Pathology, University of California, San Diego, La Jolla, California. Moores Cancer Center, University of California, San Diego, La Jolla, California
| | - Sharmeela Kaushal
- Moores Cancer Center, University of California, San Diego, La Jolla, California
| | - Cristina Metildi
- Moores Cancer Center, University of California, San Diego, La Jolla, California. Division of Surgical Oncology, Department of Surgery, University of California, San Diego, La Jolla, California
| | - Andrew M Lowy
- Moores Cancer Center, University of California, San Diego, La Jolla, California. Division of Surgical Oncology, Department of Surgery, University of California, San Diego, La Jolla, California
| | - Michael Bouvet
- Moores Cancer Center, University of California, San Diego, La Jolla, California. Division of Surgical Oncology, Department of Surgery, University of California, San Diego, La Jolla, California
| | - Jonathan A Kelber
- Department of Biology, California State University, Northridge, California
| | - Richard L Klemke
- Department of Pathology, University of California, San Diego, La Jolla, California. Moores Cancer Center, University of California, San Diego, La Jolla, California.
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Abstract
In addition to the small and large ribosomal subunits, aminoacyl-tRNAs, and an mRNA, cellular protein synthesis is dependent on translation factors. The eukaryotic translation initiation factor 5A (eIF5A) and its bacterial ortholog elongation factor P (EF-P) were initially characterized based on their ability to stimulate methionyl-puromycin (Met-Pmn) synthesis, a model assay for protein synthesis; however, the function of these factors in cellular protein synthesis has been difficult to resolve. Interestingly, a conserved lysine residue in eIF5A is post-translationally modified to hypusine and the corresponding lysine residue in EF-P from at least some bacteria is modified by the addition of a β-lysine moiety. In this review, we provide a summary of recent data that have identified a novel role for the translation factor eIF5A and its hypusine modification in the elongation phase of protein synthesis and more specifically in stimulating the production of proteins containing runs of consecutive proline residues.
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Affiliation(s)
- Thomas E. Dever
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Erik Gutierrez
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Byung-Sik Shin
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Li T, Belda-Palazón B, Ferrando A, Alepuz P. Fertility and polarized cell growth depends on eIF5A for translation of polyproline-rich formins in Saccharomyces cerevisiae. Genetics 2014; 197:1191-200. [PMID: 24923804 PMCID: PMC4125393 DOI: 10.1534/genetics.114.166926] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 06/05/2014] [Indexed: 01/15/2023] Open
Abstract
eIF5A is an essential and evolutionary conserved translation elongation factor, which has recently been proposed to be required for the translation of proteins with consecutive prolines. The binding of eIF5A to ribosomes occurs upon its activation by hypusination, a modification that requires spermidine, an essential factor for mammalian fertility that also promotes yeast mating. We show that in response to pheromone, hypusinated eIF5A is required for shmoo formation, localization of polarisome components, induction of cell fusion proteins, and actin assembly in yeast. We also show that eIF5A is required for the translation of Bni1, a proline-rich formin involved in polarized growth during shmoo formation. Our data indicate that translation of the polyproline motifs in Bni1 is eIF5A dependent and this translation dependency is lost upon deletion of the polyprolines. Moreover, an exogenous increase in Bni1 protein levels partially restores the defect in shmoo formation seen in eIF5A mutants. Overall, our results identify eIF5A as a novel and essential regulator of yeast mating through formin translation. Since eIF5A and polyproline formins are conserved across species, our results also suggest that eIF5A-dependent translation of formins could regulate polarized growth in such processes as fertility and cancer in higher eukaryotes.
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Affiliation(s)
- Tianlu Li
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, E-46100 Burjassot, Valencia, Spain
| | - Borja Belda-Palazón
- Instituto de Biología Molecular y Celular de Plantas, Centro Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, 46022 Valencia, Spain
| | - Alejandro Ferrando
- Instituto de Biología Molecular y Celular de Plantas, Centro Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, 46022 Valencia, Spain
| | - Paula Alepuz
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, E-46100 Burjassot, Valencia, Spain
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Frey AG, Nandal A, Park JH, Smith PM, Yabe T, Ryu MS, Ghosh MC, Lee J, Rouault TA, Park MH, Philpott CC. Iron chaperones PCBP1 and PCBP2 mediate the metallation of the dinuclear iron enzyme deoxyhypusine hydroxylase. Proc Natl Acad Sci U S A 2014; 111:8031-6. [PMID: 24843120 PMCID: PMC4050543 DOI: 10.1073/pnas.1402732111] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although cells express hundreds of metalloenzymes, the mechanisms by which apoenzymes receive their metal cofactors are largely unknown. Poly(rC)-binding proteins PCBP1 and PCBP2 are multifunctional adaptor proteins that bind iron and deliver it to ferritin for storage or to prolyl and asparagyl hydroxylases to metallate the mononuclear iron center. Here, we show that PCBP1 and PCBP2 also deliver iron to deoxyhypusine hydroxylase (DOHH), the dinuclear iron enzyme required for hypusine modification of the translation factor eukaryotic initiation factor 5A. Cells depleted of PCBP1 or PCBP2 exhibited loss of DOHH activity and loss of the holo form of the enzyme in cells, particularly when cells were made mildly iron-deficient. Lysates containing PCBP1 and PCBP2 converted apo-DOHH to holo-DOHH in vitro with greater efficiency than lysates lacking PCBP1 or PCBP2. PCBP1 bound to DOHH in iron-treated cells but not in control or iron-deficient cells. Depletion of PCBP1 or PCBP2 had no effect on the cytosolic Fe-S cluster enzyme xanthine oxidase but led to loss of cytosolic aconitase activity. Loss of aconitase activity was not accompanied by gain of RNA-binding activity, a pattern suggesting the incomplete disassembly of the [4Fe-4S] cluster. PCBP depletions had minimal effects on total cellular iron, mitochondrial iron levels, and heme synthesis. Thus, PCBP1 and PCBP2 may serve as iron chaperones to multiple classes of cytosolic nonheme iron enzymes and may have a particular role in restoring metal cofactors that are spontaneously lost in iron deficient cells.
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Affiliation(s)
- Avery G Frey
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Anjali Nandal
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Jong Hwan Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
| | - Pamela M Smith
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Toshiki Yabe
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Moon-Suhn Ryu
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Manik C Ghosh
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892; and
| | - Jaekwon Lee
- Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, NE 68516
| | - Tracey A Rouault
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892; and
| | - Myung Hee Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
| | - Caroline C Philpott
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892;
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Qin X, Liu X, Shan B, Shi L, Sharma S, Wu J, Lin Y. Inhibition of eIF5A results in aberrant uterine natural killer cell function and embryo loss in mice. Am J Reprod Immunol 2014; 71:229-40. [PMID: 24382123 PMCID: PMC4030494 DOI: 10.1111/aji.12194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 12/03/2013] [Indexed: 01/20/2023] Open
Abstract
PROBLEM The role of eukaryotic initiation factor 5A (eIF5A) in feto-maternal immunotolerance is poorly understood. METHODS OF STUDY The effects of N1-guanyl-1,7-diaminoheptane (GC7), an inhibitor of eIF5A, on the proportion and function of natural killer (NK) cell subsets were investigated using flow cytometry, immunofluorescence, CCK8 assay, TUNEL assay, DNA fragmentation analysis, mitochondrial membrane potential assay, and Western blotting. RESULTS Inhibition of eIF5A by GC7 increased embryo loss and reduced the percentage of NK cells in the uterus and spleen. GC7 treatment caused inhibition of NK cell proliferation in a time- and dose-dependent manner. GC7 also induced apoptosis of NK cells. GC7 treatment increased the protein levels of FasL, bax, p53, and cleaved caspase-3. Moreover, GC7 caused loss of mitochondrial membrane potential in NK cells. CONCLUSION Inhibition of eIF5A results in aberrant NK cell function and increased embryo loss.
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Affiliation(s)
- Xiaoli Qin
- Department of Obstetrics and Gynecology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Xiaorui Liu
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Bin Shan
- Medical Sciences, Washington State University Spokane, Spokane, WA, USA
| | - Lijuan Shi
- Department of Obstetrics and Gynecology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Surendra Sharma
- Department of Pediatrics, Women and Infants Hospital of Rhode Island, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Ji Wu
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, China
| | - Yi Lin
- Department of Obstetrics and Gynecology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
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Hydroxylation of the eukaryotic ribosomal decoding center affects translational accuracy. Proc Natl Acad Sci U S A 2014; 111:4019-24. [PMID: 24550462 DOI: 10.1073/pnas.1311750111] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The mechanisms by which gene expression is regulated by oxygen are of considerable interest from basic science and therapeutic perspectives. Using mass spectrometric analyses of Saccharomyces cerevisiae ribosomes, we found that the amino acid residue in closest proximity to the decoding center, Pro-64 of the 40S subunit ribosomal protein Rps23p (RPS23 Pro-62 in humans) undergoes posttranslational hydroxylation. We identify RPS23 hydroxylases as a highly conserved eukaryotic subfamily of Fe(II) and 2-oxoglutarate dependent oxygenases; their catalytic domain is closely related to transcription factor prolyl trans-4-hydroxylases that act as oxygen sensors in the hypoxic response in animals. The RPS23 hydroxylases in S. cerevisiae (Tpa1p), Schizosaccharomyces pombe and green algae catalyze an unprecedented dihydroxylation modification. This observation contrasts with higher eukaryotes, where RPS23 is monohydroxylated; the human Tpa1p homolog OGFOD1 catalyzes prolyl trans-3-hydroxylation. TPA1 deletion modulates termination efficiency up to ∼10-fold, including of pathophysiologically relevant sequences; we reveal Rps23p hydroxylation as its molecular basis. In contrast to most previously characterized accuracy modulators, including antibiotics and the prion state of the S. cerevisiae translation termination factor eRF3, Rps23p hydroxylation can either increase or decrease translational accuracy in a stop codon context-dependent manner. We identify conditions where Rps23p hydroxylation status determines viability as a consequence of nonsense codon suppression. The results reveal a direct link between oxygenase catalysis and the regulation of gene expression at the translational level. They will also aid in the development of small molecules altering translational accuracy for the treatment of genetic diseases linked to nonsense mutations.
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Dihazi GH, Bibi A, Jahn O, Nolte J, Mueller GA, Engel W, Dihazi H. Impact of the antiproliferative agent ciclopirox olamine treatment on stem cells proteome. World J Stem Cells 2013; 5:9-25. [PMID: 23362436 PMCID: PMC3557350 DOI: 10.4252/wjsc.v5.i1.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 09/19/2012] [Accepted: 12/20/2012] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the proteome changes of stem cells due to ciclopirox olamine (CPX) treatment compared to control and retinoic acid treated cells. METHODS Stem cells (SCs) are cells, which have the ability to continuously divide and differentiate into various other kinds of cells. Murine embryonic stem cells (ESCs) and multipotent adult germline stem cells (maGSCs) were treated with CPX, which has been shown to have an antiproliferative effect on stem cells, and compared to stem cells treated with retinoic acid (RA), which is known to have a differentiating effect on stem cells. Classical proteomic techniques like 2-D gel electrophoresis and differential in-gel electrophoresis (DIGE) were used to generate 2D protein maps from stem cells treated with RA or CPX as well as from non-treated stem cells. The resulting 2D gels were scanned and the digitalized images were collated with the help of Delta 2D software. The differentially expressed proteins were analyzed by a MALDI-TOF-TOF mass spectrometer, and the identified proteins were investigated and categorized using bioinformatics. RESULTS Treatment of stem cells with CPX, a synthetic antifungal clinically used to treat superficial mycoses, resulted in an antiproliferative effect in vitro, without impairment of pluripotency. To understand the mechanisms induced by CPX treatments which results in arrest of cell cycle without any marked effect on pluripotency, a comparative proteomics study was conducted. The obtained data revealed that the CPX impact on cell proliferation was accompanied with a significant alteration in stem cell proteome. By peptide mass fingerprinting and tandem mass spectrometry combined with searches of protein sequence databases, a set of 316 proteins was identified, corresponding to a library of 125 non-redundant proteins. With proteomic analysis of ESCs and maGSCs treated with CPX and RA, we could identify more than 90 single proteins, which were differently expressed in both cell lines. We could highlight, that CPX treatment of stem cells, with subsequent proliferation inhibition, resulted in an alteration of the expression of 56 proteins compared to non-treated cells, and 54 proteins compared to RA treated cells. Bioinformatics analysis of the regulated proteins demonstrated their involvement in various biological processes. To our interest, a number of proteins have potential roles in the regulation of cell proliferation either directly or indirectly. Furthermore the classification of the altered polypeptides according to their main known/postulated functions revealed that the majority of these proteins are involved in molecular functions like nucleotide binding and metal ion binding, and biological processes like nucleotide biosynthetic processes, gene expression, embryonic development, regulation of transcription, cell cycle processes, RNA and mRNA processing. Proteins, which are involved in nucleotide biosynthetic process and proteolysis, were downregulated in CPX treated cells compared to control, as well as in RA treated cells, which may explain the cell cycle arrest. Moreover, proteins which were involved in cell death, positive regulation of biosynthetic process, response to organic substance, glycolysis, anti-apoptosis, and phosphorylation were downregulated in RA treated cells compared to control and CPX treated cells. CONCLUSION The CPX treatment of SCs results in downregulation of nucleotide binding proteins and leads to cell cycle stop without impairment of pluripotency.
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Affiliation(s)
- Gry H Dihazi
- Gry H Dihazi, Asima Bibi, Gerhard A Mueller, Hassan Dihazi, Department of Nephrology and Rheumatology, Georg-August University Goettingen, D-37075 Goettingen, Germany
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Depletion of cellular polyamines, spermidine and spermine, causes a total arrest in translation and growth in mammalian cells. Proc Natl Acad Sci U S A 2013; 110:2169-74. [PMID: 23345430 DOI: 10.1073/pnas.1219002110] [Citation(s) in RCA: 186] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The polyamines, putrescine, spermidine, and spermine, are essential polycations, intimately involved in the regulation of cellular proliferation. Although polyamines exert dynamic effects on the conformation of nucleic acids and macromolecular synthesis in vitro, their specific functions in vivo are poorly understood. We investigated the cellular function of polyamines by overexpression of a key catabolic enzyme, spermidine/spermine N(1)-acetyltransferase 1 (SAT1) in mammalian cells. Transient cotransfection of HeLa cells with GFP and SAT1 vectors suppressed GFP protein expression without lowering its mRNA level, an indication that the block in GFP expression was not at transcription, but at translation. Fluorescence single-cell imaging also revealed specific inhibition of endogenous protein synthesis in the SAT1 overexpressing cells, without any inhibition of synthesis of DNA or RNA. Overexpression of SAT1 using a SAT1 adenovirus led to rapid depletion of cellular spermidine and spermine, total inhibition of protein synthesis, and growth arrest within 24 h. The SAT1 effect is most likely due to depletion of spermidine and spermine, because stable polyamine analogs that are not substrates for SAT1 restored GFP and endogenous protein synthesis. Loss of polysomes with increased 80S monosomes in the polyamine-depleted cells suggests a direct role for polyamines in translation initiation. Our data provide strong evidence for a primary function of polyamines, spermidine and spermine, in translation in mammalian cells.
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Caraglia M, Park MH, Wolff EC, Marra M, Abbruzzese A. eIF5A isoforms and cancer: two brothers for two functions? Amino Acids 2013; 44:103-9. [PMID: 22139412 PMCID: PMC3536922 DOI: 10.1007/s00726-011-1182-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 11/22/2011] [Indexed: 12/11/2022]
Abstract
Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the unusual amino acid hypusine [N(ε)-(4-amino-2-hydroxybutyl)lysine]. The role of hypusine formation in the eIF5A protein in the regulation of cell proliferation and apoptosis is addressed in the present review. Moreover, vertebrates carry two genes that encode two eIF5A isoforms, eIF5A-1 and eIF5A-2, which, in humans, are 84% identical. However, the biological functions of these two isoforms may be significantly different. In fact, eIF5A-1 is demonstrable in most cells of different histogenesis, whereas eIF5A-2 protein is detectable only in certain human cancer cells or tissues, suggesting its role as a potential oncogene. In this review we focus our attention on the involvement of eIF5A-1 in the triggering of an apoptotic program and in the regulation of cell proliferation. In addition, the potential oncogenic role and prognostic significance of eIF5A-2 in the prediction of the survival of cancer patients is described. eIF5A-1 and/or the eIF5A-2 isoform may serve as a new molecular diagnostic or prognostic marker or as a molecular target for anti-cancer therapy.
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Affiliation(s)
- M Caraglia
- Department of Biochemistry and Biophysics, Second University of Naples, Via Costantinopoli, 16, 80138 Naples, Italy.
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Sievert H, Venz S, Platas-Barradas O, Dhople VM, Schaletzky M, Nagel CH, Braig M, Preukschas M, Pällmann N, Bokemeyer C, Brümmendorf TH, Pörtner R, Walther R, Duncan KE, Hauber J, Balabanov S. Protein-protein-interaction network organization of the hypusine modification system. Mol Cell Proteomics 2012; 11:1289-305. [PMID: 22888148 PMCID: PMC3494187 DOI: 10.1074/mcp.m112.019059] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 06/27/2012] [Indexed: 12/12/2022] Open
Abstract
Hypusine modification of eukaryotic initiation factor 5A (eIF-5A) represents a unique and highly specific post-translational modification with regulatory functions in cancer, diabetes, and infectious diseases. However, the specific cellular pathways that are influenced by the hypusine modification remain largely unknown. To globally characterize eIF-5A and hypusine-dependent pathways, we used an approach that combines large-scale bioreactor cell culture with tandem affinity purification and mass spectrometry: "bioreactor-TAP-MS/MS." By applying this approach systematically to all four components of the hypusine modification system (eIF-5A1, eIF-5A2, DHS, and DOHH), we identified 248 interacting proteins as components of the cellular hypusine network, with diverse functions including regulation of translation, mRNA processing, DNA replication, and cell cycle regulation. Network analysis of this data set enabled us to provide a comprehensive overview of the protein-protein interaction landscape of the hypusine modification system. In addition, we validated the interaction of eIF-5A with some of the newly identified associated proteins in more detail. Our analysis has revealed numerous novel interactions, and thus provides a valuable resource for understanding how this crucial homeostatic signaling pathway affects different cellular functions.
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Affiliation(s)
- Henning Sievert
- From the ‡Department of Oncology, Hematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumor Zentrum, University Hospital Eppendorf, Hamburg, Germany
| | - Simone Venz
- §Department of Medical Biochemistry and Molecular Biology, University of Greifswald, Greifswald, Germany
| | - Oscar Platas-Barradas
- ¶Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
| | - Vishnu M. Dhople
- ‖Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, Ernst-Moritz-Arndt-University of Greifswald, Greifswald, Germany
| | - Martin Schaletzky
- ¶Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
| | - Claus-Henning Nagel
- **Heinrich-Pette-Institute - Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Melanie Braig
- From the ‡Department of Oncology, Hematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumor Zentrum, University Hospital Eppendorf, Hamburg, Germany
| | - Michael Preukschas
- From the ‡Department of Oncology, Hematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumor Zentrum, University Hospital Eppendorf, Hamburg, Germany
| | - Nora Pällmann
- From the ‡Department of Oncology, Hematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumor Zentrum, University Hospital Eppendorf, Hamburg, Germany
| | - Carsten Bokemeyer
- From the ‡Department of Oncology, Hematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumor Zentrum, University Hospital Eppendorf, Hamburg, Germany
| | - Tim H. Brümmendorf
- ‡‡Clinic for Internal Medicine IV, Hematology and Oncology, University Hospital of the RWTH Aachen, Aachen, Germany
| | - Ralf Pörtner
- ¶Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
| | - Reinhard Walther
- §Department of Medical Biochemistry and Molecular Biology, University of Greifswald, Greifswald, Germany
| | - Kent E. Duncan
- §§Neuronal Translational Control Group, Center for Molecular Neurobiology, ZMNH, University of Hamburg Medical School, Hamburg, Germany
| | - Joachim Hauber
- **Heinrich-Pette-Institute - Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Stefan Balabanov
- From the ‡Department of Oncology, Hematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumor Zentrum, University Hospital Eppendorf, Hamburg, Germany
- ¶¶Division of Hematology, University Hospital Zurich, Zurich, Switzerland
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Preukschas M, Hagel C, Schulte A, Weber K, Lamszus K, Sievert H, Pällmann N, Bokemeyer C, Hauber J, Braig M, Balabanov S. Expression of eukaryotic initiation factor 5A and hypusine forming enzymes in glioblastoma patient samples: implications for new targeted therapies. PLoS One 2012; 7:e43468. [PMID: 22927971 PMCID: PMC3424167 DOI: 10.1371/journal.pone.0043468] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 07/20/2012] [Indexed: 12/23/2022] Open
Abstract
Glioblastomas are highly aggressive brain tumors of adults with poor clinical outcome. Despite a broad range of new and more specific treatment strategies, therapy of glioblastomas remains challenging and tumors relapse in all cases. Recent work demonstrated that the posttranslational hypusine modification of the eukaryotic initiation factor 5A (eIF-5A) is a crucial regulator of cell proliferation, differentiation and an important factor in tumor formation, progression and maintenance. Here we report that eIF-5A as well as the hypusine-forming enzymes deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH) are highly overexpressed in glioblastoma patient samples. Importantly, targeting eIF-5A and its hypusine modification with GC7, a specific DHS-inhibitor, showed a strong antiproliferative effect in glioblastoma cell lines in vitro, while normal human astrocytes were not affected. Furthermore, we identified p53 dependent premature senescence, a permanent cell cycle arrest, as the primary outcome in U87-MG cells after treatment with GC7. Strikingly, combined treatment with clinically relevant alkylating agents and GC7 had an additive antiproliferative effect in glioblastoma cell lines. In addition, stable knockdown of eIF-5A and DHS by short hairpin RNA (shRNA) could mimic the antiproliferative effects of GC7. These findings suggest that pharmacological inhibition of eIF-5A may represent a novel concept to treat glioblastomas and may help to substantially improve the clinical course of this tumor entity.
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Affiliation(s)
- Michael Preukschas
- Department of Oncology, Haematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumorzentrum, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Hagel
- Department of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Alexander Schulte
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kristoffer Weber
- Research Department Cell and Gene Therapy, Clinic for Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katrin Lamszus
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Henning Sievert
- Department of Oncology, Haematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumorzentrum, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nora Pällmann
- Department of Oncology, Haematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumorzentrum, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Carsten Bokemeyer
- Department of Oncology, Haematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumorzentrum, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Joachim Hauber
- Heinrich-Pette-Institute – Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Melanie Braig
- Department of Oncology, Haematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumorzentrum, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stefan Balabanov
- Department of Oncology, Haematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumorzentrum, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Chawla B, Kumar RR, Tyagi N, Subramanian G, Srinivasan N, Park MH, Madhubala R. A unique modification of the eukaryotic initiation factor 5A shows the presence of the complete hypusine pathway in Leishmania donovani. PLoS One 2012; 7:e33138. [PMID: 22438895 PMCID: PMC3306375 DOI: 10.1371/journal.pone.0033138] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 02/04/2012] [Indexed: 12/24/2022] Open
Abstract
Deoxyhypusine hydroxylase (DOHH) catalyzes the final step in the post-translational synthesis of an unusual amino acid hypusine (N(€)-(4-amino-2-hydroxybutyl) lysine), which is present on only one cellular protein, eukaryotic initiation factor 5A (eIF5A). We present here the molecular and structural basis of the function of DOHH from the protozoan parasite, Leishmania donovani, which causes visceral leishmaniasis. The L. donovani DOHH gene is 981 bp and encodes a putative polypeptide of 326 amino acids. DOHH is a HEAT-repeat protein with eight tandem repeats of α-helical pairs. Four conserved histidine-glutamate sequences have been identified that may act as metal coordination sites. A ~42 kDa recombinant protein with a His-tag was obtained by heterologous expression of DOHH in Escherichia coli. Purified recombinant DOHH effectively catalyzed the hydroxylation of the intermediate, eIF5A-deoxyhypusine (eIF5A-Dhp), in vitro. L. donovani DOHH (LdDOHH) showed ~40.6% sequence identity with its human homolog. The alignment of L. donovani DOHH with the human homolog shows that there are two significant insertions in the former, corresponding to the alignment positions 159-162 (four amino acid residues) and 174-183 (ten amino acid residues) which are present in the variable loop connecting the N- and C-terminal halves of the protein, the latter being present near the substrate binding site. Deletion of the ten-amino-acid-long insertion decreased LdDOHH activity to 14% of the wild type recombinant LdDOHH. Metal chelators like ciclopirox olamine (CPX) and mimosine significantly inhibited the growth of L. donovani and DOHH activity in vitro. These inhibitors were more effective against the parasite enzyme than the human enzyme. This report, for the first time, confirms the presence of a complete hypusine pathway in a kinetoplastid unlike eubacteria and archaea. The structural differences between the L. donovani DOHH and the human homolog may be exploited for structure based design of selective inhibitors against the parasite.
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Affiliation(s)
- Bhavna Chawla
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Ravi Ranjan Kumar
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Nidhi Tyagi
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Gowri Subramanian
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - N. Srinivasan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Myung Hee Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research (NIDCR), National Institute of Health, Bethesda, Maryland, United States of America
| | - Rentala Madhubala
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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44
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Greganova E, Bütikofer P. Ethanolamine phosphoglycerol attachment to eEF1A is not essential for normal growth of Trypanosoma brucei. Sci Rep 2012; 2:254. [PMID: 22355766 PMCID: PMC3275919 DOI: 10.1038/srep00254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/24/2012] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic elongation factor 1A (eEF1A) is the only protein modified by ethanolamine phosphoglycerol (EPG). In mammals and plants, EPG is attached to conserved glutamate residues located in eEF1A domains II and III, whereas in the unicellular eukaryote, Trypanosoma brucei, a single EPG moiety is attached to domain III. A biosynthetic precursor of EPG and structural requirements for EPG attachment to T. brucei eEF1A have been reported, but the role of this unique protein modification in cellular growth and eEF1A function has remained elusive. Here we report, for the first time in a eukaryotic cell, a model system to study potential roles of EPG. By down-regulation of EF1A expression and subsequent complementation of eEF1A function using conditionally expressed exogenous eEF1A (mutant) proteins, we show that eEF1A lacking EPG complements trypanosomes deficient in endogenous eEF1A, demonstrating that EPG attachment is not essential for normal growth of T. brucei in culture.
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45
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Dias CAO, Gregio APB, Rossi D, Galvão FC, Watanabe TF, Park MH, Valentini SR, Zanelli CF. eIF5A interacts functionally with eEF2. Amino Acids 2012; 42:697-702. [PMID: 21822730 PMCID: PMC3245752 DOI: 10.1007/s00726-011-0985-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 06/02/2011] [Indexed: 11/27/2022]
Abstract
eIF5A is highly conserved from archaea to mammals, essential for cell viability and the only protein known to contain the essential amino acid residue hypusine, generated by a unique posttranslational modification. eIF5A was originally identified as a translation initiation factor due to its ability to stimulate the formation of the first peptide bond. However, recent studies have shown that depletion of eIF5A causes a significant decrease in polysome run-off and an increase in the ribosome transit time, suggesting that eIF5A is actually involved in the elongation step of protein synthesis. We have previously shown that the depletion mutant tif51A-3 (eIF5A(C39Y/G118D)) shows a sicker phenotype when combined with the dominant negative mutant eft2 ( H699K ) of the elongation factor eEF2. In this study, we used the eIF5A(K56A) mutant to further investigate the relationship between eIF5A and eEF2. The eIF5A(K56A) mutant is temperature sensitive and has a defect in protein synthesis, but instead of causing depletion of the eIF5A protein, this mutant has a defect in hypusine modification. Like the mutant tif51A-3, the eIF5A(K56A) mutant is synthetic sick with the mutant eft2 ( H699K ) of eEF2. High-copy eEF2 not only improves cell growth of the eIF5A(K56A) mutant, but also corrects its increased cell size defect. Moreover, eEF2 suppression of the eIF5A(K56A) mutant is correlated with the improvement of total protein synthesis and with the increased resistance to the protein synthesis inhibitor hygromycin B. Finally, the polysome profile defect of the eIF5A(K56A) mutant is largely corrected by high-copy eEF2. Therefore, these results demonstrate that eIF5A is closely related to eEF2 function during translation elongation.
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Affiliation(s)
- Camila A. O. Dias
- Department of Biological Sciences, School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil
| | - Ana Paula Borges Gregio
- Department of Biological Sciences, School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil
| | - Danuza Rossi
- Department of Biological Sciences, School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil
| | - Fábio Carrilho Galvão
- Department of Biological Sciences, School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil
| | - Tatiana F. Watanabe
- Department of Biological Sciences, School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil
| | - Myung Hee Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Sandro R. Valentini
- Department of Biological Sciences, School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil
| | - Cleslei F. Zanelli
- Department of Biological Sciences, School of Pharmaceutical Sciences, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil
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Hyvönen MT, Keinänen TA, Khomutov M, Simonian A, Vepsäläinen J, Park JH, Khomutov AR, Alhonen L, Park MH. Effects of novel C-methylated spermidine analogs on cell growth via hypusination of eukaryotic translation initiation factor 5A. Amino Acids 2012; 42:685-95. [PMID: 21861168 PMCID: PMC3223563 DOI: 10.1007/s00726-011-0984-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 05/17/2011] [Indexed: 12/13/2022]
Abstract
The polyamines, putrescine, spermidine, and spermine, are ubiquitous multifunctional cations essential for cellular proliferation. One specific function of spermidine in cell growth is its role as a butylamine donor for hypusine synthesis in the eukaryotic initiation factor 5A (eIF5A). Here, we report the ability of novel mono-methylated spermidine analogs (α-MeSpd, β-MeSpd, γ-MeSpd, and ω-MeSpd) to function in the hypusination of eIF5A and in supporting the growth of DFMO-treated DU145 cells. We also tested them as substrates and inhibitors for deoxyhypusine synthase (DHS) in vitro. Of these compounds, α-MeSpd, β-MeSpd, and γ-MeSpd (but not ω-MeSpd) were substrates for DHS in vitro, while they all inhibited the enzyme reaction. As racemic mixtures, only α-MeSpd and β-MeSpd supported long-term growth (9-18 days) of spermidine-depleted DU145 cells, whereas γ-MeSpd and ω-MeSpd did not. The S-enantiomer of α-MeSpd, which supported long-term growth, was a good substrate for DHS in vitro, whereas the R-isomer was not. The long-term growth of DFMO-treated cells correlated with the hypusine modification of eIF5A by intracellular methylated spermidine analogs. These results underscore the critical requirement for hypusine modification in mammalian cell proliferation and provide new insights into the specificity of the deoxyhypusine synthase reaction.
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Affiliation(s)
- Mervi T. Hyvönen
- A.I. Virtanen Institute for Molecular Sciences, Biocenter Kuopio, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, FI-70211 Kuopio, Finland
| | - Tuomo A. Keinänen
- Department of Biosciences, Laboratory of Chemistry, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, FI-70211 Kuopio, Finland
| | - Maxim Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Alina Simonian
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Jouko Vepsäläinen
- Department of Biosciences, Laboratory of Chemistry, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, FI-70211 Kuopio, Finland
| | - Jong Hwan Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alex R. Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Leena Alhonen
- A.I. Virtanen Institute for Molecular Sciences, Biocenter Kuopio, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, FI-70211 Kuopio, Finland
| | - Myung Hee Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
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Zougman A, Mann M, Wiśniewski JR. Identification and characterization of a novel ubiquitous nucleolar protein 'NARR' encoded by a gene overlapping the rab34 oncogene. Nucleic Acids Res 2011; 39:7103-13. [PMID: 21586586 PMCID: PMC3167632 DOI: 10.1093/nar/gkr273] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 04/08/2011] [Accepted: 04/08/2011] [Indexed: 01/08/2023] Open
Abstract
There are only few reports on protein products originating from overlapping mammalian genes even though computational predictions suggest that an appreciable fraction of mammalian genes could potentially overlap. Mass spectrometry-based proteomics has now acquired the tools to probe proteins in an unbiased manner, providing direct evidence of the output of the genomic and gene expression machinery. In particular, proteomics can refine gene predictions and discover novel gene-processing events and gene arrangements. Here, we report the mass spectrometric discovery and biochemical validation of the novel protein encoded by a gene overlapping rab34 oncogene. The novel protein is highly conserved in mammals. In humans, it contains 13 distinct Nine-Amino acid Residue-Repeats (NARR) with the consensus sequence PRVIV(S/T)PR in which the serine or threonine residues are phosphorylated during M-phase. NARR is ubiquitously expressed and resides in nucleoli where it colocalizes with ribosomal DNA (rDNA) gene clusters. Its distribution only partially overlaps with upstream binding factor, one of the main regulators of RNA Polymerase I activity, and is entirely uncoupled from it in mitotic cells and upon inhibition of transcription. NARR only partially colocalizes with fibrillarin, the pre-ribosomal RNA-processing protein, positioning NARR in a separate niche within the rDNA cluster.
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Affiliation(s)
- Alexandre Zougman
- Max Planck Institute for Biochemistry, Department of Proteomics and Signal Trasduction, Am Klopferspitz 18, Martinsried D 82152, Germany and Cancer Research UK Clinical Centre, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Matthias Mann
- Max Planck Institute for Biochemistry, Department of Proteomics and Signal Trasduction, Am Klopferspitz 18, Martinsried D 82152, Germany and Cancer Research UK Clinical Centre, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Jacek R. Wiśniewski
- Max Planck Institute for Biochemistry, Department of Proteomics and Signal Trasduction, Am Klopferspitz 18, Martinsried D 82152, Germany and Cancer Research UK Clinical Centre, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK
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48
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Henderson A, Hershey JW. Eukaryotic translation initiation factor (eIF) 5A stimulates protein synthesis in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2011; 108:6415-9. [PMID: 21451136 PMCID: PMC3081013 DOI: 10.1073/pnas.1008150108] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Within the field of eukaryotic protein synthesis, one factor remained putative for decades: eukaryotic translation initiation factor (eIF) 5A. Because eIF5A is an essential protein required for cell proliferation, and one easily targeted by inhibitors, identifying its role in the cell remains important and urgent. Recent reports support early findings that eIF5A stimulates protein synthesis and newly assign the factor a role in elongation rather than initiation. Here we show that eIF5A directly stimulates protein synthesis on native mRNAs, that rapid depletion of eIF5A in vivo immediately leads to a 2-fold inhibition of protein synthesis, and that both the immediate and lasting effects of eIF5A depletion are a reduction in polysome size concomitant with eIF5A depletion. Addition of purified eIF5A to a depleted lysate results in a roughly 2-fold stimulation of protein synthesis in vitro, a result consistent with both older methionyl-puromycin synthesis data and more recently published findings. We find that although eIF5A is not required for protein synthesis, it stimulates the process by about 2- to 3-fold. Our data, along with other published results, reinforce the conclusion that eIF5A stimulates protein synthesis with one important difference: Polysome profiles observed immediately after eIF5A depletion are diagnostic for a role in initiation. This discrepancy is discussed.
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Affiliation(s)
- Allen Henderson
- Department of Microbiology and Immunology, University of California, 513 Parnassus Avenue, Room S-472, San Francisco, CA 94143; and
| | - John W. Hershey
- Department of Biochemistry and Molecular Medicine, University of California, 4408 Tupper Hall, Davis, CA 95616
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49
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Park JH, Dias CAO, Lee SB, Valentini SR, Sokabe M, Fraser CS, Park MH. Production of active recombinant eIF5A: reconstitution in E.coli of eukaryotic hypusine modification of eIF5A by its coexpression with modifying enzymes. Protein Eng Des Sel 2011; 24:301-9. [PMID: 21131325 PMCID: PMC3038461 DOI: 10.1093/protein/gzq110] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 11/03/2010] [Accepted: 11/03/2010] [Indexed: 11/12/2022] Open
Abstract
Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the polyamine-modified lysine, hypusine [N(ε)-(4-amino-2-hydroxybutyl)lysine]. Hypusine occurs only in eukaryotes and certain archaea, but not in eubacteria. It is formed post-translationally by two consecutive enzymatic reactions catalyzed by deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Hypusine modification is essential for the activity of eIF5A and for eukaryotic cell proliferation. eIF5A binds to the ribosome and stimulates translation in a hypusine-dependent manner, but its mode of action in translation is not well understood. Since quantities of highly pure hypusine-modified eIF5A is desired for structural studies as well as for determination of its binding sites on the ribosome, we have used a polycistronic vector, pST39, to express eIF5A alone, or to co-express human eIF5A-1 with DHS or with both DHS and DOHH in Escherichia coli cells, to engineer recombinant proteins, unmodified eIF5A, deoxyhypusine- or hypusine-modified eIF5A. We have accomplished production of three different forms of recombinant eIF5A in high quantity and purity. The recombinant hypusine-modified eIF5A was as active in methionyl-puromycin synthesis as the native, eIF5A (hypusine form) purified from mammalian tissue. The recombinant eIF5A proteins will be useful tools in future structure/function and the mechanism studies in translation.
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Affiliation(s)
- Jong Hwan Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4340, USA
| | - Camila A. O. Dias
- Department of Biological Sciences, School of Pharmaceutical Sciences, University of Estadual Paulista – UNESP, Bldg 30 Rm 211, Araraquara, SP, Brazil
| | - Seung Bum Lee
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4340, USA
| | - Sandro R. Valentini
- Department of Biological Sciences, School of Pharmaceutical Sciences, University of Estadual Paulista – UNESP, Bldg 30 Rm 211, Araraquara, SP, Brazil
| | | | - Christopher S. Fraser
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Myung Hee Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4340, USA
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50
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LEE SB, PARK JH, FOLK J, DECK JA, PEGG AE, SOKABE M, FRASER CS, PARK MH. Inactivation of eukaryotic initiation factor 5A (eIF5A) by specific acetylation of its hypusine residue by spermidine/spermine acetyltransferase 1 (SSAT1). Biochem J 2011; 433:205-13. [PMID: 20942800 PMCID: PMC3003598 DOI: 10.1042/bj20101322] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
eIF5A (eukaryotic translation initiation factor 5A) is the only cellular protein containing hypusine [Nϵ-(4-amino-2-hydroxybutyl)lysine]. eIF5A is activated by the post-translational synthesis of hypusine and the hypusine modification is essential for cell proliferation. In the present study, we report selective acetylation of the hypusine and/or deoxyhypusine residue of eIF5A by a key polyamine catabolic enzyme SSAT1 (spermidine/spermine-N1-acetyltransferase 1). This enzyme normally catalyses the N1-acetylation of spermine and spermidine to form acetyl-derivatives, which in turn are degraded to lower polyamines. Although SSAT1 has been reported to exert other effects in cells by its interaction with other cellular proteins, eIF5A is the first target protein specifically acetylated by SSAT1. Hypusine or deoxyhypusine, as the free amino acid, does not act as a substrate for SSAT1, suggesting a macromolecular interaction between eIF5A and SSAT1. Indeed, the binding of eIF5A and SSAT1 was confirmed by pull-down assays. The effect of the acetylation of hypusine on eIF5A activity was assessed by comparison of acetylated with non-acetylated bovine testis eIF5A in the methionyl-puromycin synthesis assay. The loss of eIF5A activity by this SSAT1-mediated acetylation confirms the strict structural requirement for the hypusine side chain and suggests a possible regulation of eIF5A by hypusine acetylation/deacetylation.
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Affiliation(s)
- Seung Bum LEE
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892 USA
| | - Jong Hwan PARK
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892 USA
| | - J.E. FOLK
- Chemical Biology Research Branch, National Institute of Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20892 USA
| | - Jason A. DECK
- Chemical Biology Research Branch, National Institute of Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20892 USA
| | - Anthony E. PEGG
- Department of Cellular and Molecular Physiology, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, PA, 17033 USA
| | - Masaaki SOKABE
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616
| | - Christopher S. FRASER
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Myung Hee PARK
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892 USA
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