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Baicalein, 7,8-Dihydroxyflavone and Myricetin as Potent Inhibitors of Human Ornithine Decarboxylase. Nutrients 2020; 12:nu12123867. [PMID: 33348871 PMCID: PMC7765794 DOI: 10.3390/nu12123867] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 11/23/2022] Open
Abstract
Background: Human ornithine decarboxylase (ODC) is a well-known oncogene, and the discovery of ODC enzyme inhibitors is a beneficial strategy for cancer therapy and prevention. Methods: We examined the inhibitory effects of a variety of flavone and flavonol derivatives on ODC enzymatic activity, and performed in silico molecular docking of baicalein, 7,8-dihydroxyflavone and myricetin to the whole dimer of human ODC to investigate the possible binding site of these compounds on ODC. We also examined the cytotoxic effects of these compounds with cell-based studies. Results: Baicalein, 7,8-dihydroxyflavone and myricetin exhibited significant ODC suppression activity with IC50 values of 0.88 µM, 2.54 µM, and 7.3 µM, respectively, which were much lower than that of the active-site irreversible inhibitor α-DL-difluoromethylornithine (IC50, the half maximal inhibitory concentration, of approximately 100 µM). Kinetic studies and molecular docking simulations suggested that baicalein, and 7,8-dihydroxyflavone act as noncompetitive inhibitors that are hydrogen-bonded to the region near the active site pocket in the dimer interface of the enzyme. Baicalein and myricetin suppress cell growth and induce cellular apoptosis, and both of these compounds suppress the ODC-evoked anti-apoptosis of cells. Conclusions: Therefore, we suggest that the flavone or flavonol derivatives baicalein, 7,8-dihydroxyflavone, and myricetin are potent chemopreventive and chemotherapeutic agents that target ODC.
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Critical Factors in Human Antizymes that Determine the Differential Binding, Inhibition, and Degradation of Human Ornithine Decarboxylase. Biomolecules 2019; 9:biom9120864. [PMID: 31842334 PMCID: PMC6995573 DOI: 10.3390/biom9120864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/05/2019] [Accepted: 12/10/2019] [Indexed: 02/04/2023] Open
Abstract
Antizyme (AZ) is a protein that negatively regulates ornithine decarboxylase (ODC). AZ achieves this inhibition by binding to ODC to produce AZ-ODC heterodimers, abolishing enzyme activity and targeting ODC for degradation by the 26S proteasome. In this study, we focused on the biomolecular interactions between the C-terminal domain of AZ (AZ95–228) and ODC to identify the functional elements of AZ that are essential for binding, inhibiting and degrading ODC, and we also identified the crucial factors governing the differential binding and inhibition ability of AZ isoforms toward ODC. Based on the ODC inhibition and AZ-ODC binding studies, we demonstrated that amino acid residues reside within the α1 helix, β5 and β6 strands, and connecting loop between β6 and α2 (residues 142–178), which is the posterior part of AZ95–228, play crucial roles in ODC binding and inhibition. We also identified the essential elements determining the ODC-degradative activity of AZ; amino acid residues within the anterior part of AZ95–228 (residues 120–145) play crucial roles in AZ-mediated ODC degradation. Finally, we identified the crucial factors that govern the differential binding and inhibition of AZ isoforms toward ODC. Mutagenesis studies of AZ1 and AZ3 and their binding and inhibition revealed that the divergence of amino acid residues 124, 150, 166, 171, and 179 results in the differential abilities of AZ1 and AZ3 in the binding and inhibition of ODC.
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Abstract
The polyamines spermidine, spermine, and their precursor putrescine are organic polycations involved in various cellular processes and are absolutely essential for cellular proliferation. Because of their crucial function in the cell, their intracellular concentration must be maintained at optimal levels. To a large extent, this regulation is achieved through the activity of an autoregulatory loop that involves two proteins, antizyme (Az) and antizyme inhibitor (AzI), that regulate the first enzyme in polyamine biosynthesis, ornithine decarboxylase (ODC), and polyamine uptake activity in response to intracellular polyamine levels. In this Minireview, I will discuss what has been learned about the mechanism of Az expression and its physical interaction with both ODC and AzI in the regulation of polyamines.
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Affiliation(s)
- Chaim Kahana
- From the Department of Molecular Genetics, the Weizmann Institute of Science, Rehovot 76100, Israel
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4
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Ramos-Molina B, Lambertos A, Peñafiel R. Antizyme Inhibitors in Polyamine Metabolism and Beyond: Physiopathological Implications. ACTA ACUST UNITED AC 2018; 6:medsci6040089. [PMID: 30304856 PMCID: PMC6313458 DOI: 10.3390/medsci6040089] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 12/25/2022]
Abstract
The intracellular levels of polyamines, cationic molecules involved in a myriad of cellular functions ranging from cellular growth, differentiation and apoptosis, is precisely regulated by antizymes and antizyme inhibitors via the modulation of the polyamine biosynthetic and transport systems. Antizymes, which are mainly activated upon high polyamine levels, inhibit ornithine decarboxylase (ODC), the key enzyme of the polyamine biosynthetic route, and exert a negative control of polyamine intake. Antizyme inhibitors (AZINs), which are proteins highly homologous to ODC, selectively interact with antizymes, preventing their action on ODC and the polyamine transport system. In this review, we will update the recent advances on the structural, cellular and physiological functions of AZINs, with particular emphasis on the action of these proteins in the regulation of polyamine metabolism. In addition, we will describe emerging evidence that suggests that AZINs may also have polyamine-independent effects on cells. Finally, we will discuss how the dysregulation of AZIN activity has been implicated in certain human pathologies such as cancer, fibrosis or neurodegenerative diseases.
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Affiliation(s)
- Bruno Ramos-Molina
- Department of Biochemistry and Molecular Biology B and Immunology, Faculty of Medicine, University of Murcia, 30100 Murcia, Spain.
- Laboratory of Cellular and Molecular Endocrinology, Institute of Biomedical Research in Malaga (IBIMA), Virgen de la Victoria University Hospital, 29010 Málaga, Spain.
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Institute of Health Carlos III (ISCIII), 28029 Madrid, Spain.
| | - Ana Lambertos
- Department of Biochemistry and Molecular Biology B and Immunology, Faculty of Medicine, University of Murcia, 30100 Murcia, Spain.
- Biomedical Research Institute of Murcia (IMIB), 30120 Murcia, Spain.
| | - Rafael Peñafiel
- Department of Biochemistry and Molecular Biology B and Immunology, Faculty of Medicine, University of Murcia, 30100 Murcia, Spain.
- Biomedical Research Institute of Murcia (IMIB), 30120 Murcia, Spain.
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Characterization of an androgen-responsive, ornithine decarboxylase-related protein in mouse kidney. Biosci Rep 2017; 37:BSR20170163. [PMID: 28607032 PMCID: PMC5518511 DOI: 10.1042/bsr20170163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 06/09/2017] [Accepted: 06/09/2017] [Indexed: 01/26/2023] Open
Abstract
We have investigated and characterized a novel ornithine decarboxylase (ODC) related protein (ODCrp) also annotated as gm853. ODCrp shows 41% amino acid sequence identity with ODC and 38% with ODC antizyme inhibitor 1 (AZIN1). The Odcrp gene is selectively expressed in the epithelium of proximal tubuli of mouse kidney with higher expression in males than in females. Like Odc in mouse kidney, Odcrp is also androgen responsive with androgen receptor (AR)-binding loci within its regulatory region. ODCrp forms homodimers but does not heterodimerize with ODC. Although ODCrp contains 20 amino acid residues known to be necessary for the catalytic activity of ODC, no decarboxylase activity could be found with ornithine, lysine or arginine as substrates. ODCrp does not function as an AZIN, as it neither binds ODC antizyme 1 (OAZ1) nor prevents OAZ-mediated inactivation and degradation of ODC. ODCrp itself is degraded via ubiquination and mutation of Cys363 (corresponding to Cys360 of ODC) appears to destabilize the protein. Evidence for a function of ODCrp was found in ODC assays on lysates from transfected Cos-7 cells where ODCrp repressed the activity of endogenous ODC while Cys363Ala mutated ODCrp increased the enzymatic activity of endogenous ODC.
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6
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Pan S, Nikolakakis K, Adamczyk PA, Pan M, Ruby EG, Reed JL. Model-enabled gene search (MEGS) allows fast and direct discovery of enzymatic and transport gene functions in the marine bacterium Vibrio fischeri. J Biol Chem 2017; 292:10250-10261. [PMID: 28446608 DOI: 10.1074/jbc.m116.763193] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 04/23/2017] [Indexed: 12/23/2022] Open
Abstract
Whereas genomes can be rapidly sequenced, the functions of many genes are incompletely or erroneously annotated because of a lack of experimental evidence or prior functional knowledge in sequence databases. To address this weakness, we describe here a model-enabled gene search (MEGS) approach that (i) identifies metabolic functions either missing from an organism's genome annotation or incorrectly assigned to an ORF by using discrepancies between metabolic model predictions and experimental culturing data; (ii) designs functional selection experiments for these specific metabolic functions; and (iii) selects a candidate gene(s) responsible for these functions from a genomic library and directly interrogates this gene's function experimentally. To discover gene functions, MEGS uses genomic functional selections instead of relying on correlations across large experimental datasets or sequence similarity as do other approaches. When applied to the bioluminescent marine bacterium Vibrio fischeri, MEGS successfully identified five genes that are responsible for four metabolic and transport reactions whose absence from a draft metabolic model of V. fischeri caused inaccurate modeling of high-throughput experimental data. This work demonstrates that MEGS provides a rapid and efficient integrated computational and experimental approach for annotating metabolic genes, including those that have previously been uncharacterized or misannotated.
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Affiliation(s)
- Shu Pan
- From the Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Kiel Nikolakakis
- From the Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Paul A Adamczyk
- From the Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Min Pan
- the School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China, and
| | - Edward G Ruby
- the Pacific Biosciences Research Center, University of Hawaii, Manoa, Hawaii 96813
| | - Jennifer L Reed
- From the Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706,
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Qiu S, Liu J, Xing F. Antizyme inhibitor 1: a potential carcinogenic molecule. Cancer Sci 2017; 108:163-169. [PMID: 27870265 PMCID: PMC5329145 DOI: 10.1111/cas.13122] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/05/2016] [Accepted: 11/17/2016] [Indexed: 01/15/2023] Open
Abstract
Polyamines are multivalent and organic cations essential for cellular growth, proliferation, differentiation, and apoptosis. Increased levels of polyamines are closely associated with numerous forms of cancer. An autoregulatory circuit composed of ornithine decarboxylase (ODC), antizyme (AZ) and antizyme inhibitor (AZI) govern the intracellular level of polyamines. Antizyme binds with ODC to inhibit ODC activity and to promote the ubiquitin‐independent degradation of ODC. Antizyme inhibitor binds to AZ with a higher affinity than ODC. Consequently, ODC is released from the ODC–AZ complex to rescue its activity. Antizyme inhibitor increases the ODC activity to accelerate the formation of intracellular polyamines, triggering gastric and breast carcinogenesis as well as hepatocellular carcinoma and esophageal squamous cell carcinoma development. Antizyme inhibitor 1 (AZIN1), a primary member of the AZI family, has aroused more attention because of its contribution to cancer. Even though its conformation is changed by adenosine‐to‐inosine (A→I) RNA editing, it plays an important role in tumorigenesis through regulating intracellular polyamines. Encouragingly, AZIN1 has been revealed to have an additional function outside the polyamine pathway so as to bypass the deficiency of targeting the polyamine biosynthetic pathway, promising to become a critical target for cancer therapy. Here, we review the latest research advances into AZIN1 and its potential contribution to carcinogenesis.
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Affiliation(s)
- Shiqiao Qiu
- Department of Immunobiology, Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou, China.,Key Laboratory of Functional Protein Research of Guangdong, Higher Education Institutes, Jinan University, Guangzhou, China
| | - Jing Liu
- Department of Stomatology, Jinan University, Guangzhou, China
| | - Feiyue Xing
- Department of Immunobiology, Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou, China.,Key Laboratory of Functional Protein Research of Guangdong, Higher Education Institutes, Jinan University, Guangzhou, China
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Liu YC, Lee CY, Lin CL, Chen HY, Liu GY, Hung HC. Multifaceted interactions and regulation between antizyme and its interacting proteins cyclin D1, ornithine decarboxylase and antizyme inhibitor. Oncotarget 2016; 6:23917-29. [PMID: 26172301 PMCID: PMC4695161 DOI: 10.18632/oncotarget.4469] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 06/16/2015] [Indexed: 11/25/2022] Open
Abstract
Ornithine decarboxylase (ODC), cyclin D1 (CCND1) and antizyme inhibitor (AZI) promote cell growth. ODC and CCND1 can be degraded through antizyme (AZ)-mediated 26S proteasomal degradation. This paper describes a mechanistic study of the molecular interactions between AZ and its interacting proteins. The dissociation constant (Kd) of the binary AZ-CCND1 complex and the respective binding sites of AZ and CCND1 were determined. Our data indicate that CCND1 has a 4-fold lower binding affinity for AZ than does ODC and an approximately 40-fold lower binding affinity for AZ than does AZI. The Kd values of AZ-CCND1, AZ-ODC and AZ-AZI were 0.81, 0.21 and 0.02 μM, respectively. Furthermore, the Kd values for CCND1 binding to the AZ N-terminal peptide (AZ34–124) and AZ C-terminal peptide (AZ100–228) were 0.92 and 8.97 μM, respectively, indicating that the binding site of CCND1 may reside at the N-terminus of AZ, rather than the C-terminus. Our data also show that the ODC-AZ-CCND1 ternary complex may exist in equilibrium. The Kd values of the [AZ-CCND1]-ODC and [AZ-ODC]-CCND1 complexes were 1.26 and 4.93 μM, respectively. This is the first paper to report the reciprocal regulation of CCND1 and ODC through AZ-dependent 26S proteasomal degradation.
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Affiliation(s)
- Yen-Chin Liu
- Department of Life Sciences, National Chung Hsing University (NCHU), Taichung, Taiwan
| | - Chien-Yun Lee
- Department of Life Sciences, National Chung Hsing University (NCHU), Taichung, Taiwan.,Graduate Institute of Biotechnology, National Chung-Hsing University (NCHU), Taichung, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
| | - Chi-Li Lin
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Hui-Yi Chen
- Biotechnology Center, National Chung-Hsing University (NCHU), Taichung, Taiwan.,Agricultural Biotechnology Center (ABC), National Chung-Hsing University (NCHU), Taichung, Taiwan
| | - Guang-Yaw Liu
- Institute of Microbiology & Immunology, Chung Shan Medical University, Taichung, Taiwan.,Division of Allergy, Immunology, and Rheumatology, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Hui-Chih Hung
- Department of Life Sciences, National Chung Hsing University (NCHU), Taichung, Taiwan.,Agricultural Biotechnology Center (ABC), National Chung-Hsing University (NCHU), Taichung, Taiwan.,Institute of Genomics and Bioinformatics, National Chung Hsing University (NCHU), Taichung, Taiwan
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9
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Greenwood MP, Greenwood M, Paton JFR, Murphy D. Control of Polyamine Biosynthesis by Antizyme Inhibitor 1 Is Important for Transcriptional Regulation of Arginine Vasopressin in the Male Rat Hypothalamus. Endocrinology 2015; 156:2905-17. [PMID: 25961839 PMCID: PMC4511134 DOI: 10.1210/en.2015-1074] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The polyamines spermidine and spermine are small cations present in all living cells. In the brain, these cations are particularly abundant in the neurons of the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus, which synthesize the neuropeptide hormones arginine vasopressin (AVP) and oxytocin. We recently reported increased mRNA expression of antizyme inhibitor 1 (Azin1), an important regulator of polyamine synthesis, in rat SON and PVN as a consequence of 3 days of dehydration. Here we show that AZIN1 protein is highly expressed in both AVP- and oxytocin-positive magnocellular neurons of the SON and PVN together with antizyme 1 (AZ1), ornithine decarboxylase, and polyamines. Azin1 mRNA expression increased in the SON and PVN as a consequence of dehydration, salt loading, and acute hypertonic stress. In organotypic hypothalamic cultures, addition of the irreversible ornithine decarboxylase inhibitor DL-2-(difluoromethyl)-ornithine hydrochloride significantly increased the abundance of heteronuclear AVP but not heteronuclear oxytocin. To identify the function of Azin1 in vivo, lentiviral vectors that either overexpress or knock down Azin1 were stereotaxically delivered into the SON and/or PVN. Azin1 short hairpin RNA delivery resulted in decreased plasma osmolality and had a significant effect on food intake. The expression of AVP mRNA was also significantly increased in the SON by Azin1 short hairpin RNA. In contrast, Azin1 overexpression in the SON decreased AVP mRNA expression. We have therefore identified AZIN1, and hence by inference, polyamines as novel regulators of the expression of the AVP gene.
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Affiliation(s)
- Michael P Greenwood
- School of Clinical Sciences (M.P.G., M.G., D.M.), University of Bristol, Bristol BS1 3NY, United Kingdom; School of Physiology and Pharmacology (J.F.R.P.), University of Bristol, Bristol BS8 1TD, United Kingdom; and Department of Physiology (D.M.), University of Malaya, Kuala Lumpur, Malaysia 50603
| | - Mingkwan Greenwood
- School of Clinical Sciences (M.P.G., M.G., D.M.), University of Bristol, Bristol BS1 3NY, United Kingdom; School of Physiology and Pharmacology (J.F.R.P.), University of Bristol, Bristol BS8 1TD, United Kingdom; and Department of Physiology (D.M.), University of Malaya, Kuala Lumpur, Malaysia 50603
| | - Julian F R Paton
- School of Clinical Sciences (M.P.G., M.G., D.M.), University of Bristol, Bristol BS1 3NY, United Kingdom; School of Physiology and Pharmacology (J.F.R.P.), University of Bristol, Bristol BS8 1TD, United Kingdom; and Department of Physiology (D.M.), University of Malaya, Kuala Lumpur, Malaysia 50603
| | - David Murphy
- School of Clinical Sciences (M.P.G., M.G., D.M.), University of Bristol, Bristol BS1 3NY, United Kingdom; School of Physiology and Pharmacology (J.F.R.P.), University of Bristol, Bristol BS8 1TD, United Kingdom; and Department of Physiology (D.M.), University of Malaya, Kuala Lumpur, Malaysia 50603
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10
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Liao C, Wang Y, Tan X, Sun L, Liu S. Discovery of novel inhibitors of human S-adenosylmethionine decarboxylase based on in silico high-throughput screening and a non-radioactive enzymatic assay. Sci Rep 2015; 5:10754. [PMID: 26030749 PMCID: PMC5377238 DOI: 10.1038/srep10754] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 04/27/2015] [Indexed: 12/12/2022] Open
Abstract
Natural polyamines are small polycationic molecules essential for cell growth and development, and elevated level of polyamines is positively correlated with various cancers. As a rate-limiting enzyme of the polyamine biosynthetic pathway, S-adenosylmethionine decarboxylase (AdoMetDC) has been an attractive drug target. In this report, we present the discovery of novel human AdoMetDC (hAdoMetDC) inhibitors by coupling computational and experimental tools. We constructed a reasonable computational structure model of hAdoMetDC that is compatible with general protocols for high-throughput drug screening, and used this model in in silico screening of hAdoMetDC inhibitors against a large compound library using a battery of computational tools. We also established and validated a simple, economic, and non-radioactive enzymatic assay, which can be adapted for experimental high-throughput screening of hAdoMetDC inhibitors. Finally, we obtained an hAdoMetDC inhibitor lead with a novel scaffold. This study provides both new tools and a new lead for the developing of novel hAdoMetDC inhibitors.
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Affiliation(s)
- Chenzeng Liao
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
- College of Medical Science, China Three Gorges University, Yichang 443002, China
| | - Yanlin Wang
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
- College of Medical Science, China Three Gorges University, Yichang 443002, China
| | - Xiao Tan
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
- College of Medical Science, China Three Gorges University, Yichang 443002, China
| | - Lidan Sun
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
- College of Medical Science, China Three Gorges University, Yichang 443002, China
| | - Sen Liu
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
- College of Medical Science, China Three Gorges University, Yichang 443002, China
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11
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Ma R, Jiang D, Kang B, Bai L, He H, Chen Z, Yi Z. Molecular cloning and mRNA expression analysis of antizyme inhibitor 1 in the ovarian follicles of the Sichuan white goose. Gene 2015; 568:55-60. [PMID: 25959024 DOI: 10.1016/j.gene.2015.05.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 04/03/2015] [Accepted: 05/06/2015] [Indexed: 11/18/2022]
Abstract
Antizyme inhibitor 1 (Azin1) plays critical roles in various cellular pathways, including ornithine decarboxylase regulation, polyamine anabolism and uptake and cell proliferation. However, the molecular characteristics of the AZIN1 gene and its expression profile in goose tissues and ovarian follicles have not been reported. In this study, the AZIN1 cDNA of the Sichuan white goose (Anser cygnoides) was cloned, and analyzed for its phylogenetic and physiochemical properties. The expression profile of AZIN1 mRNA in geese tissues and ovarian follicles were examined using quantitative real-time PCR. The results showed that the open reading frame of the AZIN1 cDNA is 1,353 bp in length, encoding a 450 amino acid protein with a molecular weight of 50 kDa. Out of all tissues examined, AZIN1 expression was highest in the adrenal gland and lowest in breast muscle. There was also a high expression of AZIN1 in the cerebellum and isthmus of oviduct. With follicular development, AZIN1 gene expression gradually increased, and its expression in F1 was significantly higher than in F5 (P<0.05). AZIN1 expression was also significantly higher in the POF1 than in the other follicles (P<0.05), and there was a low mRNA expression of AZIN1 in atretic follicles. The results of AZIN1 expression profiling in ovarian follicles suggest that AZIN1 may play an important role in the progression of follicular development, potentially through regulating polyamine levels.
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Affiliation(s)
- Rong Ma
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China
| | - Dongmei Jiang
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China
| | - Bo Kang
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China.
| | - Lin Bai
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China
| | - Hui He
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China
| | - Ziyu Chen
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China
| | - Zhixin Yi
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China
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12
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Lee CY, Liu YL, Lin CL, Liu GY, Hung HC. Functional roles of the dimer-interface residues in human ornithine decarboxylase. PLoS One 2014; 9:e104865. [PMID: 25140796 PMCID: PMC4139326 DOI: 10.1371/journal.pone.0104865] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 07/13/2014] [Indexed: 01/06/2023] Open
Abstract
Ornithine decarboxylase (ODC) catalyzes the decarboxylation of ornithine to putrescine and is the rate-limiting enzyme in the polyamine biosynthesis pathway. ODC is a dimeric enzyme, and the active sites of this enzyme reside at the dimer interface. Once the enzyme dissociates, the enzyme activity is lost. In this paper, we investigated the roles of amino acid residues at the dimer interface regarding the dimerization, protein stability and/or enzyme activity of ODC. A multiple sequence alignment of ODC and its homologous protein antizyme inhibitor revealed that 5 of 9 residues (residues 165, 277, 331, 332 and 389) are divergent, whereas 4 (134, 169, 294 and 322) are conserved. Analytical ultracentrifugation analysis suggested that some dimer-interface amino acid residues contribute to formation of the dimer of ODC and that this dimerization results from the cooperativity of these interface residues. The quaternary structure of the sextuple mutant Y331S/Y389D/R277S/D332E/V322D/D134A was changed to a monomer rather than a dimer, and the Kd value of the mutant was 52.8 µM, which is over 500-fold greater than that of the wild-type ODC (ODC_WT). In addition, most interface mutants showed low but detectable or negligible enzyme activity. Therefore, the protein stability of these interface mutants was measured by differential scanning calorimetry. These results indicate that these dimer-interface residues are important for dimer formation and, as a consequence, are critical for enzyme catalysis.
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Affiliation(s)
- Chien-Yun Lee
- Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
| | - Yi-Liang Liu
- Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan
- Institute of Microbiology and Immunology and Division of Allergy, Immunology and Rheumatology, Chung Shan Medical University and Hospital, Taichung, Taiwan
| | - Chih-Li Lin
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Guang-Yaw Liu
- Institute of Microbiology and Immunology and Division of Allergy, Immunology and Rheumatology, Chung Shan Medical University and Hospital, Taichung, Taiwan
- * E-mail: (HCH); (GYL)
| | - Hui-Chih Hung
- Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan
- Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
- Agricultural Biotechnology Center (ABC), National Chung-Hsing University (NCHU), Taichung, Taiwan
- * E-mail: (HCH); (GYL)
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13
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Ramos-Molina B, Lambertos A, Lopez-Contreras AJ, Kasprzak JM, Czerwoniec A, Bujnicki JM, Cremades A, Peñafiel R. Structural and degradative aspects of ornithine decarboxylase antizyme inhibitor 2. FEBS Open Bio 2014; 4:510-21. [PMID: 24967154 PMCID: PMC4066113 DOI: 10.1016/j.fob.2014.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 01/11/2023] Open
Abstract
Ornithine decarboxylase (ODC) is the key enzyme in the polyamine biosynthetic pathway. ODC levels are controlled by polyamines through the induction of antizymes (AZs), small proteins that inhibit ODC and target it to proteasomal degradation without ubiquitination. Antizyme inhibitors (AZIN1 and AZIN2) are proteins homologous to ODC that bind to AZs and counteract their negative effect on ODC. Whereas ODC and AZIN1 are well-characterized proteins, little is known on the structure and stability of AZIN2, the lastly discovered member of this regulatory circuit. In this work we first analyzed structural aspects of AZIN2 by combining biochemical and computational approaches. We demonstrated that AZIN2, in contrast to ODC, does not form homodimers, although the predicted tertiary structure of the AZIN2 monomer was similar to that of ODC. Furthermore, we identified conserved residues in the antizyme-binding element, whose substitution drastically affected the capacity of AZIN2 to bind AZ1. On the other hand, we also found that AZIN2 is much more labile than ODC, but it is highly stabilized by its binding to AZs. Interestingly, the administration of the proteasome inhibitor MG132 caused differential effects on the three AZ-binding proteins, having no effect on ODC, preventing the degradation of AZIN1, but unexpectedly increasing the degradation of AZIN2. Inhibitors of the lysosomal function partially prevented the effect of MG132 on AZIN2. These results suggest that the degradation of AZIN2 could be also mediated by an alternative route to that of proteasome. These findings provide new relevant information on this unique regulatory mechanism of polyamine metabolism.
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Key Words
- AZ, antizyme
- AZBE, antizyme-binding element
- AZIN, antizyme inhibitor
- Antizyme
- Antizyme-binding element
- ERGIC, endoplasmic reticulum-Golgi intermediate compartment
- GDT_TS, global distance test total score
- HA, hemagglutinin
- HEK, human embryonic kidney
- Homology modeling
- ODC, ornithine decarboxylase
- PAGE, polyacrylamide gel electrophoresis
- Polyamines
- Proteasome inhibitors
- Protein degradation
- RMSD, root-mean-square deviation
- TGN, trans-Golgi network
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Affiliation(s)
- Bruno Ramos-Molina
- Department of Biochemistry and Molecular Biology B and Immunology, University of Murcia, Spain ; Instituto Murciano de Investigación Biosanitaria (IMIB), Murcia, Spain
| | - Ana Lambertos
- Department of Biochemistry and Molecular Biology B and Immunology, University of Murcia, Spain ; Instituto Murciano de Investigación Biosanitaria (IMIB), Murcia, Spain
| | | | - Joanna M Kasprzak
- Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Anna Czerwoniec
- Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Janusz M Bujnicki
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Asunción Cremades
- Department of Biochemistry and Molecular Biology B and Immunology, University of Murcia, Spain ; Instituto Murciano de Investigación Biosanitaria (IMIB), Murcia, Spain
| | - Rafael Peñafiel
- Department of Biochemistry and Molecular Biology B and Immunology, University of Murcia, Spain ; Instituto Murciano de Investigación Biosanitaria (IMIB), Murcia, Spain
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14
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Obakan P, Arisan ED, Calcabrini A, Agostinelli E, Bolkent S, Palavan-Unsal N. Activation of polyamine catabolic enzymes involved in diverse responses against epibrassinolide-induced apoptosis in LNCaP and DU145 prostate cancer cell lines. Amino Acids 2014; 46:553-64. [PMID: 23963538 DOI: 10.1007/s00726-013-1574-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/31/2013] [Indexed: 12/11/2022]
Abstract
Epibrassinolide (EBR) is a biologically active compound of the brassinosteroids, steroid-derived plant growth regulator family. Generally, brassinosteroids are known for their cell expansion and cell division-promoting roles. Recently, EBR was shown as a potential apoptotic inducer in various cancer cells without affecting the non-tumor cell growth. Androgen signaling controls cell proliferation through the interaction with the androgen receptor (AR) in the prostate gland. Initially, the development of prostate cancer is driven by androgens. However, in later stages, a progress to the androgen-independent stage is observed, resulting in metastatic prostate cancer. The androgen-responsive or -irresponsive cells are responsible for tumor heterogeneity, which is an obstacle to effective anti-cancer therapy. Polyamines are amine-derived organic compounds, known for their role in abnormal cell proliferation as well as during malignant transformation. Polyamine catabolism-targeting agents are being investigated against human cancers. Many chemotherapeutic agents including polyamine analogs have been demonstrated to induce polyamine catabolism that depletes polyamine levels and causes apoptosis in tumor models. In our study, we aimed to investigate the mechanism of apoptotic cell death induced by EBR, related with polyamine biosynthetic and catabolic pathways in LNCaP (AR+), DU145 (AR-) prostate cancer cell lines and PNT1a normal prostate epithelial cell line. Induction of apoptotic cell death was observed in prostate cancer cell lines after EBR treatment. In addition, EBR induced the decrease of intracellular polyamine levels, accompanied by a significant ornithine decarboxylase (ODC) down-regulation in each prostate cancer cell and also modulated ODC antizyme and antizyme inhibitor expression levels only in LNCaP cells. Catabolic enzymes SSAT and PAO expression levels were up-regulated in both cell lines; however, the specific SSAT and PAO siRNA treatments prevented the EBR-induced apoptosis only in LNCaP (AR+) cells. In a similar way, MDL 72,527, the specific PAO and SMO inhibitor, co-treatment with EBR during 24 h, reduced the formation of cleaved fragments of PARP in LNCaP (AR+) cells.
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Affiliation(s)
- Pinar Obakan
- Department of Molecular Biology and Genetics, Istanbul Kultur University, Atakoy Campus, Bakirkoy, 34156, Istanbul, Turkey
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15
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Lange I, Geerts D, Feith DJ, Mocz G, Koster J, Bachmann AS. Novel interaction of ornithine decarboxylase with sepiapterin reductase regulates neuroblastoma cell proliferation. J Mol Biol 2013; 426:332-46. [PMID: 24096079 DOI: 10.1016/j.jmb.2013.09.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/21/2013] [Accepted: 09/25/2013] [Indexed: 01/24/2023]
Abstract
Ornithine decarboxylase (ODC) is the sentinel enzyme in polyamine biosynthesis. Both ODC and polyamines regulate cell division, proliferation, and apoptosis. Sepiapterin reductase (SPR) catalyzes the last step in the biosynthesis of tetrahydrobiopterin (BH4), an essential cofactor of nitric oxide synthase, and has been implicated in neurological diseases but not yet in cancer. In this study, we present compelling evidence that native ODC and SPR physically interact, and we defined the individual amino acid residues involved in both enzymes using in silico protein-protein docking simulations. The resulting heterocomplex is a surprisingly compact structure, featuring two energetically and structurally equivalent binding modes both in monomer and in dimer conformations. The novel interaction between ODC and SPR proteins was confirmed under physiological conditions by co-immunoprecipitation and co-localization in neuroblastoma (NB) cells. Importantly, we showed that siRNA (small interfering RNA)-mediated knockdown of SPR expression significantly reduced endogenous ODC enzyme activity in NB cells, thus demonstrating the biological relevance of the ODC-SPR interaction. Finally, in a cohort of 88 human NB tumors, we found that high SPR mRNA expression correlated significantly with poor survival prognosis using a Kaplan-Meier analysis (log-rank test, P=5 × 10(-4)), suggesting an oncogenic role for SPR in NB tumorigenesis. In conclusion, we showed that ODC binds SPR and thus propose a new concept in which two well-characterized biochemical pathways converge via the interaction of two enzymes. We identified SPR as a novel regulator of ODC enzyme activity and, based on clinical evidence, present a model in which SPR drives ODC-mediated malignant progression in NB.
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Affiliation(s)
- Ingo Lange
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, HI 96720, USA
| | - Dirk Geerts
- Department of Pediatric Oncology/Hematology, Sophia Children's Hospital, Erasmus University Medical Center, 3015 GE Rotterdam, The Netherlands
| | - David J Feith
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Gabor Mocz
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Jan Koster
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - André S Bachmann
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, HI 96720, USA; Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA.
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16
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Chen J, Liu Q, Yang X, Wu X, Zhang D, He A, Zhan X. Characterization and immunolocalization of mutated ornithine decarboxylase antizyme from Angiostrongylus cantonensis. Mol Biochem Parasitol 2013; 190:76-81. [DOI: 10.1016/j.molbiopara.2013.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 06/14/2013] [Accepted: 06/18/2013] [Indexed: 10/26/2022]
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17
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Liu YC, Hsu DH, Huang CL, Liu YL, Liu GY, Hung HC. Determinants of the differential antizyme-binding affinity of ornithine decarboxylase. PLoS One 2011; 6:e26835. [PMID: 22073206 PMCID: PMC3207831 DOI: 10.1371/journal.pone.0026835] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 10/05/2011] [Indexed: 01/26/2023] Open
Abstract
Ornithine decarboxylase (ODC) is a ubiquitous enzyme that is conserved in all species from bacteria to humans. Mammalian ODC is degraded by the proteasome in a ubiquitin-independent manner by direct binding to the antizyme (AZ). In contrast, Trypanosoma brucei ODC has a low binding affinity toward AZ. In this study, we identified key amino acid residues that govern the differential AZ binding affinity of human and Trypanosoma brucei ODC. Multiple sequence alignments of the ODC putative AZ-binding site highlights several key amino acid residues that are different between the human and Trypanosoma brucei ODC protein sequences, including residue 119, 124,125, 129, 136, 137 and 140 (the numbers is for human ODC). We generated a septuple human ODC mutant protein where these seven bases were mutated to match the Trypanosoma brucei ODC protein sequence. The septuple mutant protein was much less sensitive to AZ inhibition compared to the WT protein, suggesting that these amino acid residues play a role in human ODC-AZ binding. Additional experiments with sextuple mutants suggest that residue 137 plays a direct role in AZ binding, and residues 119 and 140 play secondary roles in AZ binding. The dissociation constants were also calculated to quantify the affinity of the ODC-AZ binding interaction. The Kd value for the wild type ODC protein-AZ heterodimer ([ODC_WT]-AZ) is approximately 0.22 μM, while the Kd value for the septuple mutant-AZ heterodimer ([ODC_7M]-AZ) is approximately 12.4 μM. The greater than 50-fold increase in [ODC_7M]-AZ binding affinity shows that the ODC-7M enzyme has a much lower binding affinity toward AZ. For the mutant proteins ODC_7M(-Q119H) and ODC_7M(-V137D), the Kd was 1.4 and 1.2 μM, respectively. These affinities are 6-fold higher than the WT_ODC Kd, which suggests that residues 119 and 137 play a role in AZ binding.
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Affiliation(s)
- Yen-Chin Liu
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
| | - Den-Hua Hsu
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
| | - Chi-Liang Huang
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
| | - Yi-Liang Liu
- Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan
- Division of Allergy, Immunology, and Rheumatology, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Guang-Yaw Liu
- Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan
- Division of Allergy, Immunology, and Rheumatology, Chung Shan Medical University Hospital, Taichung, Taiwan
- * E-mail: (HCH); (GYL)
| | - Hui-Chih Hung
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
- * E-mail: (HCH); (GYL)
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18
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Hsieh JY, Yang JY, Lin CL, Liu GY, Hung HC. Minimal antizyme peptide fully functioning in the binding and inhibition of ornithine decarboxylase and antizyme inhibitor. PLoS One 2011; 6:e24366. [PMID: 21931692 PMCID: PMC3170320 DOI: 10.1371/journal.pone.0024366] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 08/08/2011] [Indexed: 01/10/2023] Open
Abstract
Antizyme (AZ) is a protein with 228 amino acid residues that regulates ornithine decarboxylase (ODC) by binding to ODC and dissociating its homodimer, thus inhibiting its enzyme activity. Antizyme inhibitor (AZI) is homologous to ODC, but has a higher affinity than ODC for AZ. In this study, we quantified the biomolecular interactions between AZ and ODC as well as AZ and AZI to identify functional AZ peptides that could bind to ODC and AZI and inhibit their function as efficiently as the full-length AZ protein. For these AZ peptides, the inhibitory ability of AZ_95-228 was similar to that of AZ_WT. Furthermore, AZ_95-176 displayed an inhibition (IC50: 0.20 µM) similar to that of AZ-95-228 (IC50: 0.16 µM), even though a large segment spanning residues 177–228 was deleted. However, further deletion of AZ_95-176 from either the N-terminus or the C-terminus decreased its ability to inhibit ODC. The AZ_100-176 and AZ_95-169 peptides displayed a noteworthy decrease in ability to inhibit ODC, with IC50 values of 0.43 and 0.37 µM, respectively. The AZ_95-228, AZ_100-228 and AZ_95-176 peptides had IC50 values comparable to that of AZ_WT and formed AZ-ODC complexes with Kd,AZ-ODC values of 1.5, 5.3 and 5.6 µM, respectively. Importantly, our data also indicate that AZI can rescue AZ peptide-inhibited ODC enzyme activity and that it can bind to AZ peptides with a higher affinity than ODC. Together, these data suggest that these truncated AZ proteins retain their AZI-binding ability. Thus, we suggest that AZ_95-176 is the minimal AZ peptide that is fully functioning in the binding of ODC and AZI and inhibition of their function.
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Affiliation(s)
- Ju-Yi Hsieh
- Department of Life Sciences and Institute of Bioinformatics, National Chung Hsing University, Taichung, Taiwan
| | - Jung-Yen Yang
- National Nano Device Laboratories and Department of Electrical Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Chih-Li Lin
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Guang-Yaw Liu
- Institute of Microbiology & Immunology, Chung Shan Medical University, and Division of Allergy, Immunology, and Rheumatology, Chung Shan Medical University Hospital, Taichung, Taiwan
- * E-mail: (H-CH); (G-YL)
| | - Hui-Chih Hung
- Department of Life Sciences and Institute of Bioinformatics, National Chung Hsing University, Taichung, Taiwan
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
- * E-mail: (H-CH); (G-YL)
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19
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Liu YC, Liu YL, Su JY, Liu GY, Hung HC. Critical factors governing the difference in antizyme-binding affinities between human ornithine decarboxylase and antizyme inhibitor. PLoS One 2011; 6:e19253. [PMID: 21552531 PMCID: PMC3084279 DOI: 10.1371/journal.pone.0019253] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 03/24/2011] [Indexed: 12/18/2022] Open
Abstract
Both ornithine decarboxylase (ODC) and its regulatory protein, antizyme inhibitor (AZI), can bind with antizyme (AZ), but the latter has a higher AZ-binding affinity. The results of this study clearly identify the critical amino acid residues governing the difference in AZ-binding affinities between human ODC and AZI. Inhibition experiments using a series of ODC mutants suggested that residues 125 and 140 may be the key residues responsible for the differential AZ-binding affinities. The ODC_N125K/M140K double mutant demonstrated a significant inhibition by AZ, and the IC50 value of this mutant was 0.08 µM, three-fold smaller than that of ODC_WT. Furthermore, the activity of the AZ-inhibited ODC_N125K/M140K enzyme was hardly rescued by AZI. The dissociation constant (Kd) of the [ODC_N125K/M140K]-AZ heterodimer was approximately 0.02 µM, which is smaller than that of WT_ODC by approximately 10-fold and is very close to the Kd value of AZI_WT, suggesting that ODC_N125K/M140K has an AZ-binding affinity higher than that of ODC_WT and similar to that of AZI. The efficiency of the AZI_K125N/K140M double mutant in the rescue of AZ-inhibited ODC enzyme activity was less than that of AZI_WT. The Kd value of [AZI_K125N/K140M]-AZ was 0.18 µM, nine-fold larger than that of AZI_WT and close to the Kd value of ODC_WT, suggesting that AZI_K125N/K140M has an AZ-binding affinity lower than that of AZI_WT and similar to that of ODC. These data support the hypothesis that the differences in residues 125 and 140 in ODC and AZI are responsible for the differential AZ-binding affinities.
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Affiliation(s)
- Yen-Chin Liu
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
| | - Yi-Liang Liu
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
- Division of Allergy, Immunology and Rheumatology and Institute of Immunology, Chung-Shan Medical University and Hospital, Taichung, Taiwan
| | - Jia-Yang Su
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
| | - Guang-Yaw Liu
- Division of Allergy, Immunology and Rheumatology and Institute of Immunology, Chung-Shan Medical University and Hospital, Taichung, Taiwan
- * E-mail: (HCH); (GYL)
| | - Hui-Chih Hung
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
- * E-mail: (HCH); (GYL)
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20
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Abstract
This chapter provides an overview of the polyamine field and introduces the 32 other chapters that make up this volume. These chapters provide a wide range of methods, advice, and background relevant to studies of the function of polyamines, the regulation of their content, their role in disease, and the therapeutic potential of drugs targeting polyamine content and function. The methodology provided in this new volume will enable laboratories already working in this area to expand their experimental techniques and facilitate the entry of additional workers into this rapidly expanding field.
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Affiliation(s)
- Anthony E Pegg
- College of Medicine, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, PA, USA
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21
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Ivanov IP, Firth AE, Atkins JF. Recurrent Emergence of Catalytically Inactive Ornithine Decarboxylase Homologous Forms That Likely Have Regulatory Function. J Mol Evol 2010; 70:289-302. [DOI: 10.1007/s00239-010-9331-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 02/17/2010] [Indexed: 10/19/2022]
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