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Tsuge H, Habuka N, Yoshida T. General ADP-Ribosylation Mechanism Based on the Structure of ADP-Ribosyltransferase-Substrate Complexes. Toxins (Basel) 2024; 16:313. [PMID: 39057953 PMCID: PMC11281641 DOI: 10.3390/toxins16070313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 07/06/2024] [Accepted: 07/09/2024] [Indexed: 07/28/2024] Open
Abstract
ADP-ribosylation is a ubiquitous modification of proteins and other targets, such as nucleic acids, that regulates various cellular functions in all kingdoms of life. Furthermore, these ADP-ribosyltransferases (ARTs) modify a variety of substrates and atoms. It has been almost 60 years since ADP-ribosylation was discovered. Various ART structures have been revealed with cofactors (NAD+ or NAD+ analog). However, we still do not know the molecular mechanisms of ART. It needs to be better understood how ART specifies the target amino acids or bases. For this purpose, more information is needed about the tripartite complex structures of ART, the cofactors, and the substrates. The tripartite complex is essential to understand the mechanism of ADP-ribosyltransferase. This review updates the general ADP-ribosylation mechanism based on ART tripartite complex structures.
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Affiliation(s)
- Hideaki Tsuge
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 6038555, Japan
| | - Noriyuki Habuka
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 6038555, Japan
| | - Toru Yoshida
- Faculty of Sciences, Japan Women’s University, Tokyo 1120015, Japan
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2
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Goodwin K, Nelson CM. Analysis of Cre lines for targeting embryonic airway smooth muscle. Dev Biol 2023; 496:63-72. [PMID: 36706974 PMCID: PMC10041960 DOI: 10.1016/j.ydbio.2023.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 01/09/2023] [Accepted: 01/22/2023] [Indexed: 01/26/2023]
Abstract
During development of the embryonic mouse lung, the pulmonary mesenchyme differentiates into smooth muscle that wraps around the airway epithelium. Inhibiting smooth muscle differentiation leads to cystic airways, while enhancing it stunts epithelial branching. These findings support a conceptual model wherein the differentiation of smooth muscle sculpts the growing epithelium into branches at precise positions and with stereotyped morphologies. Unfortunately, most approaches to manipulate the differentiation of airway smooth muscle rely on pharmacological or physical perturbations that are conducted ex vivo. Here, we explored the use of diphtheria toxin-based genetic ablation strategies to eliminate airway smooth muscle in the embryonic mouse lung. Surprisingly, neither airway smooth muscle wrapping nor epithelial branching were affected in embryos in which the expression of diphtheria toxin or its receptor were driven by several different smooth muscle-specific Cre lines. Close examination of spatial patterns of Cre activity in the embryonic lung revealed that none of these commonly used Cre lines target embryonic airway smooth muscle robustly or specifically. Our findings demonstrate the need for airway smooth muscle-specific Cre lines that are active in the embryonic lung, and serve as a resource for researchers contemplating the use of these commonly used Cre lines for studying embryonic airway smooth muscle.
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Affiliation(s)
- Katharine Goodwin
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, 08544, USA
| | - Celeste M Nelson
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA.
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The Buzz about ADP-Ribosylation Toxins from Paenibacillus larvae, the Causative Agent of American Foulbrood in Honey Bees. Toxins (Basel) 2021; 13:toxins13020151. [PMID: 33669183 PMCID: PMC7919650 DOI: 10.3390/toxins13020151] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/02/2021] [Accepted: 02/11/2021] [Indexed: 11/26/2022] Open
Abstract
The Gram-positive, spore-forming bacterium Paenibacillus larvae is the etiological agent of American Foulbrood, a highly contagious and often fatal honey bee brood disease. The species P. larvae comprises five so-called ERIC-genotypes which differ in virulence and pathogenesis strategies. In the past two decades, the identification and characterization of several P. larvae virulence factors have led to considerable progress in understanding the molecular basis of pathogen-host-interactions during P. larvae infections. Among these virulence factors are three ADP-ribosylating AB-toxins, Plx1, Plx2, and C3larvin. Plx1 is a phage-born toxin highly homologous to the pierisin-like AB-toxins expressed by the whites-and-yellows family Pieridae (Lepidoptera, Insecta) and to scabin expressed by the plant pathogen Streptomyces scabiei. These toxins ADP-ribosylate DNA and thus induce apoptosis. While the presumed cellular target of Plx1 still awaits final experimental proof, the classification of the A subunits of the binary AB-toxins Plx2 and C3larvin as typical C3-like toxins, which ADP-ribosylate Rho-proteins, has been confirmed experimentally. Normally, C3-exoenzymes do not occur together with a B subunit partner, but as single domain toxins. Interestingly, the B subunits of the two P. larvae C3-like toxins are homologous to the B-subunits of C2-like toxins with striking structural similarity to the PA-63 protomer of Bacillus anthracis.
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Crystal structure and structure-based mutagenesis of actin-specific ADP-ribosylating toxin CPILE-a as novel enterotoxin. PLoS One 2017; 12:e0171278. [PMID: 28199340 PMCID: PMC5310789 DOI: 10.1371/journal.pone.0171278] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/17/2017] [Indexed: 01/07/2023] Open
Abstract
Unusual outbreaks of food poisoning in Japan were reported in which Clostridium perfringens was strongly suspected to be the cause based on epidemiological information and fingerprinting of isolates. The isolated strains lack the typical C. perfringens enterotoxin (CPE) but secrete a new enterotoxin consisting of two components: C. perfringens iota-like enterotoxin-a (CPILE-a), which acts as an enzymatic ADP-ribosyltransferase, and CPILE-b, a membrane binding component. Here we present the crystal structures of apo-CPILE-a, NAD+-CPILE-a and NADH-CPILE-a. Though CPILE-a structure has high similarity with known iota toxin-a (Ia) with NAD+, it possesses two extra-long protruding loops from G262-S269 and E402-K408 that are distinct from Ia. Based on the Ia-actin complex structure, we focused on actin-binding interface regions (I-V) including two protruding loops (PT) and examined how mutations in these regions affect the ADP-ribosylation activity of CPILE-a. Though some site-directed mutagenesis studies have already been conducted on the actin binding site of Ia, in the present study, mutagenesis studies were conducted against both α- and β/γ-actin in CPILE-a and Ia. Interestingly, CPILE-a ADP-ribosylates both α- and β/γ-actin, but its sensitivity towards β/γ-actin is 36% compared with α-actin. Our results contrast to that only C2-I ADP-ribosylates β/γ-actin. We also showed that PT-I and two convex-concave interactions in CPILE-a are important for actin binding. The current study is the first detailed analysis of site-directed mutagenesis in the actin binding region of Ia and CPILE-a against both α- and β/γ-actin.
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Tsuge H, Yoshida T, Tsurumura T. Conformational plasticity is crucial for C3-RhoA complex formation by ARTT-loop. Pathog Dis 2015; 73:ftv094. [PMID: 26474844 DOI: 10.1093/femspd/ftv094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2015] [Indexed: 01/22/2023] Open
Abstract
ADP-ribosylation is an important post-translational protein modification catalyzed by bacterial toxins and eukaryotic endogenous ADP-ribosyltransferases. Bacterial binary toxins and C3-like toxins recognize and ADP-ribosylate actin Arg177 and RhoA Asn41, respectively. Structural and mutational studies have identified an ADP-ribosylating turn-turn loop (ARTT-loop) that has been implicated in substrate specificity and recognition, although it has not been verified. Recently, we determined the crystal structure of the C3 exoenzyme-RhoA complex. The complex structure shows how C3 recognizes Rho GTPase and provides the first structural evidence for RhoA recognition by the ARTT-loop. The complex formation mediated by the ARTT-loop is through the intrinsic plasticity of C3 and RhoA. C3 changes the conformations of both the phosphate nicotinamide-loop and the ARTT-loop by NAD(+) and RhoA binding, respectively. In contrast, RhoA changes the conformations of switch I and II regions upon C3 binding with a particular conformation, irrespective of the bound nucleotide (GTP or GDP).
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Affiliation(s)
- Hideaki Tsuge
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences and Structural Biology Research Center, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
| | - Toru Yoshida
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences and Structural Biology Research Center, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
| | - Toshiharu Tsurumura
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences and Structural Biology Research Center, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
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6
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Astrocyte Depletion Impairs Redox Homeostasis and Triggers Neuronal Loss in the Adult CNS. Cell Rep 2015; 12:1377-84. [PMID: 26299968 DOI: 10.1016/j.celrep.2015.07.051] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 07/01/2015] [Accepted: 07/24/2015] [Indexed: 02/08/2023] Open
Abstract
Although the importance of reactive astrocytes during CNS pathology is well established, the function of astroglia in adult CNS homeostasis is less well understood. With the use of conditional, astrocyte-restricted protein synthesis termination, we found that selective paralysis of GFAP(+) astrocytes in vivo led to rapid neuronal cell loss and severe motor deficits. This occurred while structural astroglial support still persisted and in the absence of any major microvascular damage. Whereas loss of astrocyte function did lead to microglial activation, this had no impact on the neuronal loss and clinical decline. Neuronal injury was caused by oxidative stress resulting from the reduced redox scavenging capability of dysfunctional astrocytes and could be prevented by the in vivo treatment with scavengers of reactive oxygen and nitrogen species (ROS/RNS). Our results suggest that the subpopulation of GFAP(+) astrocytes maintain neuronal health by controlling redox homeostasis in the adult CNS.
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Transgenic Strategies to Study Podocyte Loss and Regeneration. Stem Cells Int 2015; 2015:678347. [PMID: 26089920 PMCID: PMC4451768 DOI: 10.1155/2015/678347] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 03/09/2015] [Accepted: 03/10/2015] [Indexed: 01/22/2023] Open
Abstract
Podocyte death and regeneration are major topics in kidney research but remain controversial. Data obtained in humans demonstrate the existence of cells sited along Bowman's capsule that behave as podocyte progenitors in vitro and in in vivo mouse models of podocyte injury xenotrasplanted with this human-derived population. However, this podocyte reservoir still remains elusive in murine models, where it could be more easily studied. Transgenic models can be a powerful tool to identify this population and to better understand its dynamics and hierarchies in both physiological and pathological conditions. Indeed, exploiting transgenic approaches allows detecting, at the single cell level, movements, cell death, and replacement. Moreover, through lineage tracing it is now possible to identify specific population increase and to point out clonal expansions during or after the regenerative processes. However, applying transgenic strategies to study glomerular regeneration requires the search of markers to unequivocally identify this progenitor population. Achieving this aim would lead to a deep comprehension of the biological processes that underlie glomerular regeneration and clarify how different cell pools interface during this phase. Here we discuss strategies that have been used and new approaches in transgenic models finalized to study podocyte loss and subsequent replacement.
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Song Y, Xia A, Lee HY, Wang R, Ricci AJ, Oghalai JS. Activity-dependent regulation of prestin expression in mouse outer hair cells. J Neurophysiol 2015; 113:3531-42. [PMID: 25810486 DOI: 10.1152/jn.00869.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/19/2015] [Indexed: 12/11/2022] Open
Abstract
Prestin is a membrane protein necessary for outer hair cell (OHC) electromotility and normal hearing. Its regulatory mechanisms are unknown. Several mouse models of hearing loss demonstrate increased prestin, inspiring us to investigate how hearing loss might feedback onto OHCs. To test whether centrally mediated feedback regulates prestin, we developed a novel model of inner hair cell loss. Injection of diphtheria toxin (DT) into adult CBA mice produced significant loss of inner hair cells without affecting OHCs. Thus, DT-injected mice were deaf because they had no afferent auditory input despite OHCs continuing to receive normal auditory mechanical stimulation and having normal function. Patch-clamp experiments demonstrated no change in OHC prestin, indicating that loss of information transfer centrally did not alter prestin expression. To test whether local mechanical feedback regulates prestin, we used Tecta(C1509G) mice, where the tectorial membrane is malformed and only some OHCs are stimulated. OHCs connected to the tectorial membrane had normal prestin levels, whereas OHCs not connected to the tectorial membrane had elevated prestin levels, supporting an activity-dependent model. To test whether the endocochlear potential was necessary for prestin regulation, we studied Tecta(C1509G) mice at different developmental ages. OHCs not connected to the tectorial membrane had lower than normal prestin levels before the onset of the endocochlear potential and higher than normal prestin levels after the onset of the endocochlear potential. Taken together, these data indicate that OHC prestin levels are regulated through local feedback that requires mechanoelectrical transduction currents. This adaptation may serve to compensate for variations in the local mechanical environment.
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Affiliation(s)
- Yohan Song
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California
| | - Anping Xia
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California
| | - Hee Yoon Lee
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California
| | - Rosalie Wang
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California
| | - Anthony J Ricci
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California
| | - John S Oghalai
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California
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Cebrian C, Asai N, D'Agati V, Costantini F. The number of fetal nephron progenitor cells limits ureteric branching and adult nephron endowment. Cell Rep 2014; 7:127-37. [PMID: 24656820 DOI: 10.1016/j.celrep.2014.02.033] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/23/2014] [Accepted: 02/22/2014] [Indexed: 01/16/2023] Open
Abstract
Nephrons, the functional units of the kidney, develop from progenitor cells (cap mesenchyme [CM]) surrounding the epithelial ureteric bud (UB) tips. Reciprocal signaling between UB and CM induces nephrogenesis and UB branching. Although low nephron number is implicated in hypertension and renal disease, the mechanisms that determine nephron number are obscure. To test the importance of nephron progenitor cell number, we genetically ablated 40% of these cells, asking whether this would limit kidney size and nephron number or whether compensatory mechanisms would allow the developing organ to recover. The reduction in CM cell number decreased the rate of branching, which in turn allowed the number of CM cells per UB tip to normalize, revealing a self-correction mechanism. However, the retarded UB branching impaired kidney growth, leaving a permanent nephron deficit. Thus, the number of fetal nephron progenitor cells is an important determinant of nephron endowment, largely via its effect on UB branching.
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Affiliation(s)
- Cristina Cebrian
- Department of Genetics and Development, Columbia University, New York, NY 10032, USA
| | - Naoya Asai
- Department of Genetics and Development, Columbia University, New York, NY 10032, USA
| | - Vivette D'Agati
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Frank Costantini
- Department of Genetics and Development, Columbia University, New York, NY 10032, USA.
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Tsuge H, Tsurumura T. Reaction Mechanism of Mono-ADP-Ribosyltransferase Based on Structures of the Complex of Enzyme and Substrate Protein. Curr Top Microbiol Immunol 2014; 384:69-87. [PMID: 24990621 DOI: 10.1007/82_2014_415] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mono-ADP-ribosylation is a post-translational protein modification catalyzed by bacterial toxins and exoenzymes that function as ADP-ribosyltransferases. Despite the importance of this modification, the reaction mechanism remains poorly understood due to a lack of information on the crystal structure of these enzymes in complex with a substrate protein. Recently, the structures of two such complexes became available, which shed new light on the mechanisms of mono-ADP-ribosylation. In this review, we consider the reaction mechanism based on the structures of ADP-ribosyltransferases in complex with a substrate protein.
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Affiliation(s)
- Hideaki Tsuge
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto, 603-8555, Japan,
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11
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Ma X, Lv P, Ye S, Zhang Y, Li S, Kan C, Fan L, Liu R, Luo D, Wang A, Yang W, Yang S, Bai X, Lu Y, Ma D, Xi L, Wang S. DT390-triTMTP1, a Novel Fusion Protein of Diphtheria Toxin with Tandem Repeat TMTP1 Peptide, Preferentially Targets Metastatic Tumors. Mol Pharm 2012. [PMID: 23198829 DOI: 10.1021/mp300125k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiangyi Ma
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Peng Lv
- Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, People's Republic of China
| | - Shuangmei Ye
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Yiqun Zhang
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Shu Li
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Chunyi Kan
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Liangsheng Fan
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Ronghua Liu
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Danfeng Luo
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Aiping Wang
- Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, People's Republic of China
| | - Wanhua Yang
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Shuhong Yang
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Xiangyang Bai
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Yunping Lu
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Ding Ma
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Ling Xi
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
| | - Shixuan Wang
- Cancer Biology
Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue,
Wuhan, Hubei 430030, People's Republic of China
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Primary oligodendrocyte death does not elicit anti-CNS immunity. Nat Neurosci 2012; 15:543-50. [PMID: 22366759 DOI: 10.1038/nn.3062] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 01/27/2012] [Indexed: 12/12/2022]
Abstract
Anti-myelin immunity is commonly thought to drive multiple sclerosis, yet the initial trigger of this autoreactivity remains elusive. One of the proposed factors for initiating this disease is the primary death of oligodendrocytes. To specifically test such oligodendrocyte death as a trigger for anti-CNS immunity, we inducibly killed oligodendrocytes in an in vivo mouse model. Strong microglia-macrophage activation followed oligodendrocyte death, and myelin components in draining lymph nodes made CNS antigens available to lymphocytes. However, even conditions favoring autoimmunity-bystander activation, removal of regulatory T cells, presence of myelin-reactive T cells and application of demyelinating antibodies-did not result in the development of CNS inflammation after oligodendrocyte death. In addition, this lack of reactivity was not mediated by enhanced myelin-specific tolerance. Thus, in contrast with previously reported impairments of oligodendrocyte physiology, diffuse oligodendrocyte death alone or in conjunction with immune activation does not trigger anti-CNS immunity.
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13
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Kautz-Neu K, Meyer RG, Clausen BE, von Stebut E. Leishmaniasis, contact hypersensitivity and graft-versus-host disease: understanding the role of dendritic cell subsets in balancing skin immunity and tolerance. Exp Dermatol 2011; 19:760-71. [PMID: 20590820 DOI: 10.1111/j.1600-0625.2010.01116.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Dendritic cells (DC) are key elements of the immune system. In peripheral tissues, they function as sentinels taking up and processing antigens. After migration to the draining lymph nodes, the DC either present antigenic peptides by themselves or transfer them to lymph node-resident DC. The skin is the primary interface between the body and the environment and host's various DC subsets, including dermal DC (dDC) and Langerhans cells (LC). Because of their anatomical position in the epidermis, LC are believed to be responsible for induction of adaptive cutaneous immune responses. The functions of LC and dDC in the skin immune system in vivo are manifold, and it is still discussed controversially whether the differentiation of T-cell subtypes (e.g. effector T cells and regulatory T cells) may be initiated by distinct DC subtypes. As skin DC are able to promote or downmodulate immune responses, we chose different skin diseases (cutaneous leishmaniasis, contact hypersensitivity, UV radiation-induced suppression, and graft-versus-host disease) to describe the biological interactions between different DC subtypes and T cells that lead to the development of efficient or unwanted immune responses. A detailed knowledge about the immune modulatory capacity of different cutaneous DC subsets might be helpful to specifically target these cells through the skin during therapeutic interventions.
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Affiliation(s)
- Kordula Kautz-Neu
- Department of Dermatology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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14
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A diphtheria toxin interleukin-3 fusion protein synergizes with tyrosine kinase inhibitors in killing leukemic progenitors from BCR/ABL positive acute leukemia. Leuk Res 2010; 34:1035-42. [DOI: 10.1016/j.leukres.2009.12.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 11/04/2009] [Accepted: 12/16/2009] [Indexed: 11/22/2022]
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15
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Caballero I, Piedrahita JA. Evaluation of theSerratia MarcescensNuclease (NucA) as a Transgenic Cell Ablation System in Porcine. Anim Biotechnol 2009; 20:177-85. [DOI: 10.1080/10495390903048235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Su Y, Li SY, Ghosh S, Ortiz J, Hogge DE, Frankel AE. Characterization of variant diphtheria toxin-interleukin-3 fusion protein, DTIL3K116W, for phase I clinical trials. Biologicals 2009; 38:144-9. [PMID: 19783458 DOI: 10.1016/j.biologicals.2009.08.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 08/17/2009] [Accepted: 08/18/2009] [Indexed: 01/02/2023] Open
Abstract
We have produced clinical grade of DTIL3K116W, a variant diphtheria toxin-interleukin-3 fusion protein, for treatment of acute myeloid leukemia. The product was filter sterilized, aseptically vialed, and stored at -80 degrees C. It was characterized by Coomassie-stained SDS-PAGE, endotoxin assay, cytotoxicity assay, sterility, mass spectroscopy, receptor binding affinity, ADP-ribosylation, inhibition of normal human CFU-GM, disulfide bond analysis, immunoblots, stability, size exclusion chromatography-HPLC, sequencing, and immunohistochemistry. Vialed product was sterile in 0.25 M NaCl/5 mM Tris, pH 7.9, and had a protein concentration of 1.08 mg/ml. Purity by SDS-PAGE was >99%. Aggregates by HPLC were <1%. Endotoxin levels were 0.296EU/mg. Peptide mapping and mass spectroscopy confirmed its composition and molecular weight. The vialed drug kept reactivity with anti-IL3 and DT antibodies. Potency study revealed a 48-h EC(50) of 0.5 pM on TF1/H-ras cell. Its binding properties were confirmed by competitive experiments showing IC(50) of 1.4 nM. ADP-ribosylation activity was equivalent to DTGM-CSF. Drug did not react with tested frozen human tissue sections by immunohistochemistry. There was no evidence of loss of solubility, proteolysis aggregation, or loss of potency over 6 months at -80 degrees C. Further, the drug was stable at 4 and 25 degrees C in the plastic syringe and administration tubing for 48 h.
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Affiliation(s)
- Yunpeng Su
- Cancer Research Institute, Scott & White Memorial Hospital, Temple, TX, USA.
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17
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Bachran C, Sutherland M, Bachran D, Fuchs H. Quantification of diphtheria toxin mediated ADP-ribosylation in a solid-phase assay. Clin Chem 2007; 53:1676-83. [PMID: 17712004 DOI: 10.1373/clinchem.2007.085365] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Because of reduced vaccination programs, the number of diphtheria infections has increased in the last decade. Diphtheria toxin (DT) is expressed by Corynebacterium diphtheriae and is responsible for the lethality of diphtheria. DT inhibits cellular protein synthesis by ADP-ribosylation of the eukaryotic elongation factor 2 (eEF2). No in vitro system for the quantification of DT enzymatic activity exists. We developed a solid-phase assay for the specific detection of ADP-ribosylation by DT. METHODS Solid phase-bound his-tag eEF2 is ADP-ribosylated by toxins using biotinylated NAD(+) as substrate, and the transferred biotinylated ADP-ribose is detected by streptavidin-peroxidase. DT enzymatic activity correlated with absorbance. We measured the amount of ADP-ribosylated eEF2 after precipitation with streptavidin-Sepharose. Quantification was done after Western blotting and detection with anti-his-tag antibody using an LAS-1000 System. RESULTS The assay detected enzymatically active DT at 30 ng/L, equivalent to 5 mU/L ADP-ribosylating activity. Pseudomonas exotoxin A (PE) activity was also detected at 100 ng/L. We verified the assay with chimeric toxins composed of the catalytic domain of DT or PE and a tumor-specific ligand. These chimeric toxins revealed increased signals at 1000 ng/L. Heat-inactivated DT and cholera toxin that ADP-ribosylates G-proteins did not show any signal increase. CONCLUSIONS The assay may be the basis for the development of a routine diagnostic assay for the detection of DT activity and highly specific inhibitors of DT.
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Affiliation(s)
- Christopher Bachran
- Zentralinstitut für Laboratoriumsmedizin und Pathobiochemie, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany
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Moss J, Vaughan M. ADP-ribosylation of guanyl nucleotide-binding regulatory proteins by bacterial toxins. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 61:303-79. [PMID: 3128060 DOI: 10.1002/9780470123072.ch6] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- J Moss
- Laboratory of Cellular Metabolism, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892
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19
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Yalcintepe L, Frankel AE, Hogge DE. Expression of interleukin-3 receptor subunits on defined subpopulations of acute myeloid leukemia blasts predicts the cytotoxicity of diphtheria toxin interleukin-3 fusion protein against malignant progenitors that engraft in immunodeficient mice. Blood 2006; 108:3530-7. [PMID: 16882709 DOI: 10.1182/blood-2006-04-013813] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe interleukin-3 receptor (IL-3R) subunits are overexpressed on acute myeloid leukemia (AML) blasts compared with normal hematopoietic cells and are thus potential targets for novel therapeutic agents. Both fluorescence-activated cell sorter (FACS) analysis and quantitative real-time reverse transcription-polymerase chain reaction (QRT-PCR) were used to quantify expression of the IL-3Rα and βc subunits on AML cells. QRT-PCR for both subunits was most predictive of killing of AML colony-forming cells (AML-CFCs) by diphtheria toxin-IL-3 fusion protein (DT388IL3). Among 19 patient samples, the relative level of the IL-3Rα was higher than the IL-3Rβc and highest in CD34+CD38-CD71- cells, enriched for candidate leukemia stem cells, compared with cell fractions depleted of such progenitors. Overall, the amount of IL-3Rβc subunit did not vary among sorted subpopulations. However, expression of both subunits varied by more than 10-fold among different AML samples for all subpopulations studied. The level of IL-3Rβc expression versus glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (set at 1000) ranged from 0.14 to 13.56 in CD34+CD38-CD71- cells from different samples; this value was correlated (r = .76, P = .05) with the ability of DT388IL3 to kill AML progenitors that engraft in β2-microglobin-deficient nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice (n = 7). Thus, quantification of IL-3R subunit expression on AML blasts predicts the effectiveness IL-3R-targeted therapy in killing primitive leukemic progenitors.
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Affiliation(s)
- Leman Yalcintepe
- Terry Fox Laboratory, BC Cancer Agency, 675 West 10th Ave, Vancouver, BC V5Z 1L3 Canada
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20
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Brockschnieder D, Pechmann Y, Sonnenberg-Riethmacher E, Riethmacher D. An improved mouse line for Cre-induced cell ablation due to diphtheria toxin A, expressed from the Rosa26 locus. Genesis 2006; 44:322-7. [PMID: 16791847 DOI: 10.1002/dvg.20218] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The means to specifically ablate cells inside of a living organism have recently been improved and facilitated by stable mouse lines, carrying conditional expression constructs for diphtheria toxin (DT) or diphtheria toxin receptor, that could be activated upon Cre-mediated recombination or the application of diphtheria toxin, respectively. We have lately described the R26:lacZ/DT-A line (Brockschnieder et al., 2004, Mol Cell Biol 24:7636-7642) in which a loxP-conditional DTA allele was introduced into the ubiquitously expressed Rosa26 locus. This strain allowed the ablation of a wide spectrum of cell types by crossing it to tissue specific Cre lines. Unexpectedly, homozygous (but not heterozygous) animals of the R26:lacZ/DT-A line developed some degenerative abnormalities in a variety of tissues. The defects were most probably caused by leaky expression of small amounts of toxin from the unrecombined lacZ(flox)DT-A cassette. Here we show that insertion of an additional transcriptional regulatory sequence (bovine growth hormone polyadenylation signal, bpA) following the lacZ open reading frame prevented the formation of any defects in homozygous mice. The modification did not affect the functionality of the lacZ(flox)DTA allele, as exemplified by the complete ablation of oligodendrocytes upon Cre-mediated recombination. The novel R26:lacZbpA(flox)DTA line is expected to greatly facilitate the reliable generation of cell type ablated mice.
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Affiliation(s)
- Damian Brockschnieder
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel.
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21
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Bektaş M, Nurten R, Ergen K, Bermek E. Endogenous ADP-ribosylation for eukaryotic elongation factor 2: evidence of two different sites and reactions. Cell Biochem Funct 2006; 24:369-80. [PMID: 16142694 DOI: 10.1002/cbf.1265] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Eukaryotic elongation factor 2 can undergo ADP-ribosylation in the absence of diphtheria toxin under the action of an endogenous transferase. The investigation which aimed to gain insight into the nature of endogenous ADP-ribosylation revealed that this reaction may be, in some cases, due to covalent binding of free ADP-ribose to elongation factor 2. Binding of free ADP-ribose, and NAD- and endogenous transferase-dependent ADP-ribosylation were suggested to be distinct reactions by different findings. Free ADP-ribose could bind to elongation factor 2 previously subjected to ADP-ribosylation by diphtheria toxin or endogenous transferase. The binding of free ADP-ribose was inhibited by neutral NH2OH, L-lysine and picrylsulfonate, whereas endogenous ADP-ribosyltransferase was inhibited by NAD glycohydrolase inhibitors and L-arginine. The ADP-ribosyl-elongation factor 2 adduct which formed upon binding of free ADP-ribose was resistant to neutral NH2OH, but decomposed almost completely upon treatment with NaOH. The product of endogenous transferase-dependent ADP- ribosylation was partially resistant to NH2OH and NaOH treatment. Moreover, this reaction was reversed in the presence of diphtheria toxin and nicotinamide. Both types of endogenous ADP-ribosylation gave rise to inhibition of polyphenylalanine synthesis. This study thus provides evidence for the presence of two different types of endogenous ADP-ribosylation of eukaryotic elongation factor 2. The respective sites involved in these reactions are distinct from one another as well as from diphthamide, the site of attack by diphtheria toxin.
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Affiliation(s)
- Muhammet Bektaş
- Istanbul University, Istanbul Faculty of Medicine, Department of Biophysics, 34390 Capa, Istanbul, Turkey.
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22
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Yang M, Liu W, Wang CY, Liu T, Zhou F, Tao J, Wang Y, Li MT. Proteomic analysis of differential protein expression in early process of pancreatic regeneration in pancreatectomized rats. Acta Pharmacol Sin 2006; 27:568-78. [PMID: 16626512 DOI: 10.1111/j.1745-7254.2006.00317.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
AIM A broad-range proteomic approach was applied to investigate the complexity of the mechanisms involved in pancreatic regeneration for identification of new targets of diabetes treatment and potential markers of pancreatic stem cells. METHODS A regeneration pancreatic model was induced by 90% partial pancreatectomy (Px) in rats. Changes in the protein expression in regenerating rat pancreas on the third day after Px, as compared with rats that received sham surgery, were analyzed by using 2-D gel electrophoresis (2-DE), mass spectrometry (MS), and mass fingerprinting. RESULTS 2-DE revealed 91 spots with at least 1.5-fold increases in expression at 3 d after pancreatectomy and 53 differentially expressed proteins that were identified by peptide mass fingerprinting (PMF). These included cell growth-related, lipid and energy metabolism-related, protein and amino acid metabolism-related proteins, and signal transduction proteins. Vimentin, CK8, L-plastin, hnRNP A2/B1, and AGAT are associated with embryogenesis and cell differentiation, and may be new potential pancreatic stem cells markers. CONCLUSION The proteome profiling technique provided a broad-based and effective approach for the rapid assimilation and identification of adaptive protein changes during pancreas regeneration induced by pancreatectomy. Our data clarify the global proteome during the pancreatic proliferation and differentiation processes, which is important for better understanding of pancreatic regeneration and for discovering of protein biomarkers for pancreatic stem cells.
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Affiliation(s)
- Ming Yang
- Department of General Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
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23
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Buch T, Heppner FL, Tertilt C, Heinen TJAJ, Kremer M, Wunderlich FT, Jung S, Waisman A. A Cre-inducible diphtheria toxin receptor mediates cell lineage ablation after toxin administration. Nat Methods 2005; 2:419-26. [PMID: 15908920 DOI: 10.1038/nmeth762] [Citation(s) in RCA: 662] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Accepted: 04/18/2005] [Indexed: 12/12/2022]
Abstract
A new system for lineage ablation is based on transgenic expression of a diphtheria toxin receptor (DTR) in mouse cells and application of diphtheria toxin (DT). To streamline this approach, we generated Cre-inducible DTR transgenic mice (iDTR) in which Cre-mediated excision of a STOP cassette renders cells sensitive to DT. We tested the iDTR strain by crossing to the T cell- and B cell-specific CD4-Cre and CD19-Cre strains, respectively, and observed efficient ablation of T and B cells after exposure to DT. In MOGi-Cre/iDTR double transgenic mice expressing Cre recombinase in oligodendrocytes, we observed myelin loss after intraperitoneal DT injections. Thus, DT crosses the blood-brain barrier and promotes cell ablation in the central nervous system. Notably, we show that the developing DT-specific antibody response is weak and not neutralizing, and thus does not impede the efficacy of DT. Our results validate the use of iDTR mice as a tool for cell ablation in vivo.
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Affiliation(s)
- Thorsten Buch
- Laboratory for Molecular Immunology, Institute for Genetics, University of Cologne, D-50931 Cologne, Germany.
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24
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Bektaş M, Akçakaya H, Aroymak A, Nurten R, Bermek E. Effect of oxidative stress on in vivo ADP-ribosylation of eukaryotic elongation factor 2. Int J Biochem Cell Biol 2005; 37:91-9. [PMID: 15381153 DOI: 10.1016/j.biocel.2004.05.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Revised: 05/24/2004] [Accepted: 05/24/2004] [Indexed: 11/16/2022]
Abstract
Different lines of evidence indicate that eukaryotic elongation factor 2 (eEF2) can be ADP-ribosylated endogenously. The physiological significance of this reaction has, however, remained unclarified. In order to address this issue we investigated the in vivo ADP-ribosylation of eEF2 and the effect of oxidative stress thereon. The investigation revealed that the endogenous ADP-ribosylation of eEF2 is complex and can take place in K562 cell lysates either under the action of endogenous transferase from [adenosine-14C]NAD or by direct binding of free [14C]ADP-ribose. These two types of ADP-ribosylation were distinguished by use of different treatments based on the chemical stability of the respective bonds formed. Under standard culture conditions, in vivo labeling of eEF2 in the presence of [14C]adenosine was reversed to about 65% in the presence of diphtheria toxin and nicotinamide. This finding implied that the modification that took place under physiological circumstances was, mainly, of an enzymic nature. On the other hand, H2O2-promoted oxidative stress gave rise to a nearly two-fold increase in the extent of in vivo labeling of eEF2. This was accompanied by a loss of eEF2 activity in polypeptide chain elongation. Oxidative stress specifically inhibited the subsequent binding of free ADP-ribose to eEF2. The results thus provide evidence that endogenous ADP-ribosylation of eEF2 can also take place by the binding of free ADP-ribose. This nonenzymic reaction appears to account primarily for in vivo ADP-ribosylation of eEF2 under oxidative stress.
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Affiliation(s)
- Muhammet Bektaş
- Department of Biophysics, Istanbul Faculty of Medicine, Istanbul University, 34390 Capa, Istanbul, Turkey.
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25
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Hogge DE, Feuring-Buske M, Gerhard B, Frankel AE. The efficacy of diphtheria-growth factor fusion proteins is enhanced by co-administration of cytosine arabinoside in an immunodeficient mouse model of human acute myeloid leukemia. Leuk Res 2004; 28:1221-6. [PMID: 15380349 DOI: 10.1016/j.leukres.2004.03.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Accepted: 03/24/2004] [Indexed: 11/30/2022]
Abstract
Addition of cytosine arabinoside (Ara-C) to truncated diphtheria toxin (DT388) fused to granulocyte macrophage-colony stimulating factor (GMCSF) or interleukin-3 (IL3) was studied in a NOD/SCID mouse model of human AML. Ara-C alone did not reduce the % human AML cells in mouse bone marrow (BM). DT388IL3 or DT388GMCSF alone reduced but did not eradicate engraftment for two of four and two of three samples, respectively. In contrast, Ara-C with DT388IL3 eliminated AML from mouse BM with one of four samples while DT388GMCSF with Ara-C eliminated or reduced AML cells as compared to mice receiving either agent alone with two of three samples.
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Affiliation(s)
- Donna E Hogge
- Terry Fox Laboratory, British Columbia Cancer Agency, 601 West 10th Avenue, Vancouver, Canada V5Z 1L3.
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26
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Xu H, He WJ, Liu WY. A novel ribotoxin with ribonuclease activity that specifically cleaves a single phosphodiester bond in rat 28S ribosomal RNA and inactivates ribosome. Arch Biochem Biophys 2004; 427:30-40. [PMID: 15178485 DOI: 10.1016/j.abb.2004.04.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2004] [Revised: 04/20/2004] [Indexed: 11/21/2022]
Abstract
A unique ribonuclease named Biota orientalis ribonuclease (Biota orientalis RNase) is purified to homogeneity from mature seeds of oriental arborvitae (Biota orientalis). The molecular mass of Biota orientalis RNase is about 13 kDa. When the concentration of Mg(2+) is 25 mM in the incubation buffer, the ribonuclease specifically cleaves the phosphodiester bond between C4453 and A4454 in region K (a region in domain VII) of 28S RNA in rat ribosome, resulting in inactivation of ribosome. Thus, it is a ribotoxin similar to alpha-sarcin. The region around C4453-A4454 in rat 28S rRNA is named "Biota orientalis RNase region." Rat ribosome treated by Biota orientalis RNase produces a small RNA fragment (S-fragment) that contains 333 nucleotides from the 3'-terminus of rat 28S rRNA. The distance between the cleavage-sites of alpha-sarcin (G4325) and Biota orientalis RNase (C4453) is 128 nucleotides. Under restricted conditions (25 mM Mg(2+)), the substrate specificity of Biota orientalis RNase is extremely high: it acts only on the "Biota orientalis RNase region" of the largest RNA in ribosomes from certain eukaryotes. The ribosome specifically damaged by Biota orientalis RNase is unable to EF-1alpha-dependently bind aminoacyl-tRNA, whereas the formation of the EF-2/GDP/ribosome complex is not affected. It is proposed that Biota orientalis RNase inactivates ribosome at least partially by interfering with the EF-1alpha-dependent binding of aminoacyl-tRNA to ribosome. Biota orientalis RNase might be a useful tool in studying the structure/function of ribosome.
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Affiliation(s)
- Hong Xu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-yang Road, Shanghai 200031, PR China
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27
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Pentz ES, Moyano MA, Thornhill BA, Sequeira Lopez MLS, Gomez RA. Ablation of renin-expressing juxtaglomerular cells results in a distinct kidney phenotype. Am J Physiol Regul Integr Comp Physiol 2003; 286:R474-83. [PMID: 14563659 DOI: 10.1152/ajpregu.00426.2003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Renin-expressing cells are peculiar in that they act as differentiated cells, producing the hormone renin, while they also seem to act as progenitors for other renal cell types. As such, they may have functions independent of their ability to generate renin/angiotensin. To test this hypothesis, we ablated renin-expressing cells during development by placing diphtheria toxin A chain (DTA) under control of the Ren1d mouse renin promoter by homologous recombination in a two-renin gene strain (Ren2 and Ren1d). Renin-expressing cells are essentially absent from kidneys in homozygotes (DTA/DTA) which, unlike wild-type mice, are unable to recruit renin-expressing cells when homeostasis is threatened. In contrast, renin staining in the submandibular gland (SMG), which expresses mainly Ren2, is normal. Homozygous mice survive normally, but the kidneys are small and have morphological abnormalities: 25% of the glomeruli are hyperplastic or atrophic, tubules are dilated and atrophic, and areas of undifferentiated cells exist near the atrophic glomeruli and tubules. However, in contrast to the very abnormal renal vessels found when renin-angiotensin system genes are deleted, the kidney vessels in homozygotes have normal wall thickness and no decrease in lumen size. Homozygotes have severely reduced kidney and plasma renin concentrations and females have reduced blood pressure. Homozygotes have elevated blood urea nitrogen and potassium levels, which are suggestive of altered renal function. We conclude that renin cells per se are necessary for the morphological integrity of the kidney and may have a role in maintenance of normal kidney function.
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Affiliation(s)
- Ellen Steward Pentz
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
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He WJ, Tang S, Liu WY. In vitro interaction of eukaryotic elongation factor 2 with synthetic oligoribonucleotide that mimics GTPase domain of rat 28S ribosomal RNA. Int J Biochem Cell Biol 2002; 34:263-8. [PMID: 11849993 DOI: 10.1016/s1357-2725(01)00122-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Eukaryotic elongation factor 2 (eEF2) catalyzed the translocation of peptidyl-tRNA from the ribosomal A site to the P site. In this paper, the interaction between eEF2 and GTD RNA, a synthetic oligoribonucleotide that mimicked the GTPase domain of rat 28S ribosomal RNA, was studied in vitro. The purified eEF2 could bind to GTD RNA, forming a stable complex. Transfer RNA competed with GTD RNA in binding to eEF2, whereas poly(A), poly(U) and poly(I, C) did not interfere with the interaction between eEF2 and GTD RNA, demonstrating that the tertiary structure of RNA might be necessary for the recognition of and binding to eEF2. The complex formation of eEF2 with GTD RNA was inhibited by SRD RNA, a synthetic oligoribonucleotide mimic of Sarcin/Ricin domain RNA of rat 28S RNA. Similarly, GTD RNA inhibited the interaction between eEF2 and SRD RNA. This fact implies that these small oligoribonucleotides probably share similar recognition or binding identity elements in their tertiary structures. In addition, the binding of eEF2 to GTD RNA could be obviously weakened by the ADP-ribosylation of eEF2 with diphtheria toxin. These results indicate that eEF2 behaves differently from prokaryotic EF-G in binding to ribosomal RNA.
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Affiliation(s)
- Wen-jun He
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, 200031, Shanghai, China
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Galicka A, Sredzińska K, Gindzieński A. Cytoplasmic inhibitor of eEF-2 ADP-ribosylation catalyzed by diphtheria toxin or endogenous transferase in rat liver cells. Biochem Biophys Res Commun 2000; 269:553-6. [PMID: 10708592 DOI: 10.1006/bbrc.2000.2322] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
eEF-2 (100 kDa) isolated from rat liver cells undergo ADP-ribosylation in the presence of diphtheria toxin or endogenous ADP-ribosyltransferase, which was co-purified with the factor. We separated the fraction free of elongation factor and endogenous transferase, which strongly inhibited the ADP-ribosylation of eEF-2. This fraction did not affect the activity of the elongation factor. The lack of endogenous transferase activity (which is potentially lethal for the cell) in the postribosomal supernatant could be the result of its inhibition. eEF-2 (65 kDa) which is probably responsible for the process of translocation (Gajko, A. et al. (1999) Biochem. Biophys. Res. Commun. 255, 535-538) was protected from ADP-ribosylation and its irreversible inactivation in the presence of the rat liver extract fraction.
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Affiliation(s)
- A Galicka
- Department of General and Organic Chemistry, Institute of Chemistry, Medical Academy, Bialystok 8, 15-230, Poland
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Falnes PO, Ariansen S, Sandvig K, Olsnes S. Requirement for prolonged action in the cytosol for optimal protein synthesis inhibition by diphtheria toxin. J Biol Chem 2000; 275:4363-8. [PMID: 10660606 DOI: 10.1074/jbc.275.6.4363] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Diphtheria toxin A-fragment enters the cytosol of target cells, where it inhibits protein synthesis by catalyzing ADP-ribosylation of elongation factor 2 (EF-2). We have here analyzed toxin-induced protein synthesis inhibition in single cells by autoradiography and compared it with inhibition of protein synthesis in the whole cell culture. The data show that half-maximal protein synthesis inhibition in the whole cell population after a short incubation time is achieved by partially inhibiting protein synthesis in basically all the cells, while half-maximal protein synthesis inhibition after a long incubation time is due to a complete protein synthesis block in about half the cells in the population. We have also compared stable and unstable A-fragment mutants with respect to the kinetics of cell intoxication. While the toxicity of the stable mutants increased with time, the unstable mutants showed a similar toxicity at early and late time points. When studying the kinetics of cell intoxication by toxins with short cytosolic half-life, we could not detect any recovery of protein synthesis at late time points when all the mutant A-fragments should be degraded. This indicates that the ADP-ribosylation of EF-2 cannot be reversed by an endogenous activity in the cells. The data indicate that entry of toxin into a cell is not associated with an immediate block in protein synthesis, and that prolonged action of single A-fragment molecules in the cytosol is sufficient to obtain complete protein synthesis inhibition at low toxin concentrations.
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Affiliation(s)
- P O Falnes
- Institute for Cancer Research, Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway
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31
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Nilsson A, Nygård O. Phosphorylation of eukaryotic elongation factor 2 in differentiating and proliferating HL-60 cells. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1268:263-8. [PMID: 7548224 DOI: 10.1016/0167-4889(95)00084-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Ca(2+)-and calmodulin-dependent protein kinase III (CaM PKIII) phosphorylates eukaryotic elongation factor 2 (eEF-2) in HL-60 cells. Dephosphorylation of the factor in these cells is catalyzed by phosphoprotein phosphatase 2A alone. Differentiation of the HL-60 cells by all-trans retinoic acid resulted in a reduced growth rate and a marked decrease in the intracellular concentration of eEF-2. During differentiation the activity of the eEF-2 kinase is gradually reduced and reaches 10% of that found in undifferentiated cells 5 days after the onset of differentiation. The capacity to dephosphorylate phospho-eEF-2 remained unaltered in the growth-arrested cells. Differentiation without reduced proliferation was induced in the HL-60 cells by interferon-gamma. Under these conditions, differentiation had no effect on the cellular content of eEF-2 or the ability to dephosphorylate phospho-eEF-2. However, the differentiated cells showed a dramatic decrease in the specific activity of the eEF-2 kinase. The results show that the cellular content of eEF-2 varies with the rate of proliferation and that the activity of the eEF-2 kinase is high in undifferentiated proliferating cells and decreases upon differentiation even under conditions of an unaltered growth rate.
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Affiliation(s)
- A Nilsson
- Department of Zoological Cell Biology, Arrhenius Laboratories E5, Stockholm University, Sweden
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Falnes PO, Olsnes S. Cell-mediated reduction and incomplete membrane translocation of diphtheria toxin mutants with internal disulfides in the A fragment. J Biol Chem 1995; 270:20787-93. [PMID: 7657662 DOI: 10.1074/jbc.270.35.20787] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Active diphtheria toxin consists of two fragments, A and B, joined by a disulfide bond. The B fragment binds to cell surface receptors and aids in the translocation of the enzymatically active A fragment to the cytosol. Normally, the toxin A fragment enters the cytosol from acidic endosomes, but translocation can also be induced at the level of the plasma membrane by exposing cells with surface-bound toxin to low pH. Recently, we showed that disulfide bonds introduced into the A fragment by mutation are inhibitory for translocation. In the present work, we found that although the complete translocation of the A fragment is blocked, three mutant toxins underwent reduction of the interfragment disulfide bond upon low pH exposure, whereas the internal disulfide in the A fragment remained intact. In the case of two of these mutants, the A fragment was released into the extracellular medium upon exposure of cell-bound toxin to low pH. The pH profile for the release of the mutant A fragments was the same as for translocation of wild-type A fragment to the cytosol, and the release was inhibited by conditions that interfere with A fragment translocation. In the case of the third mutant, which remained cell-associated upon reduction of the interfragment disulfide bond, a translocation intermediate was detected. The results show that the reduction of the interfragment disulfide bond can occur in the absence of complete translocation of the A fragment to the cytosol, and they indicate that the reduction takes place at an early stage in the translocation process. Our findings suggest that the translocation of the A fragment across the membrane is initiated at the C terminus.
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Affiliation(s)
- P O Falnes
- Institute for Cancer Research, Norwegian Radium Hospital, Montebello, Oslo
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Guillot D, Penin F, Di Pietro A, Sontag B, Lavergne J, Reboud J. GTP binding to elongation factor eEF-2 unmasks a tryptophan residue required for biological activity. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)36873-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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34
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Domenighini M, Montecucco C, Ripka WC, Rappuoli R. Computer modelling of the NAD binding site of ADP-ribosylating toxins: active-site structure and mechanism of NAD binding. Mol Microbiol 1991; 5:23-31. [PMID: 1901617 DOI: 10.1111/j.1365-2958.1991.tb01822.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Five ADP-ribosylating bacterial toxins, pertussis toxin, cholera toxin, diphtheria toxin, Escherichia LT toxin and Pseudomonas exotoxin A, show significant homology in selected segments of their sequence. Site-directed mutagenesis and chemical modification of residues within these regions cause loss of catalytic activity and of NAD binding. On the basis of these results and of molecular modelling based on the three-dimensional structure of exotoxin A, the geometry of an NAD binding site common to all the toxins is deduced and described in the paper. For diphtheria toxin, sequence similarity with exotoxin A is such that its preliminary structure can be computed by molecular modelling, whereas for the other toxins similarity appears to be restricted to the NAD binding site. Moreover, an analysis of molecular fitting of the NAD molecule into its binding cavity suggests a new model for the conformation of the bound NAD that better accounts for all available experimental information.
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35
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Carlberg U, Nilsson A, Nygård O. Functional properties of phosphorylated elongation factor 2. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 191:639-45. [PMID: 2390990 DOI: 10.1111/j.1432-1033.1990.tb19169.x] [Citation(s) in RCA: 213] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effect of phosphorylation on the functional activity of eukaryotic elongation factor 2 (eEF-2) was studied using a purified phosphorylated factor. The modified factor was unable to stimulate protein synthesis in an eEF-2-dependent rabbit reticulocyte lysate. The functional alteration was further analyzed by measuring the effects of phosphorylation on the ability of the factor to catalyse the ribosome-dependent hydrolysis of GTP. Kinetic analysis showed that both phosphorylated and unmodified factor was able to hydrolyse GTP with approximately the same maximum rate, indicating that the rate of nucleotide exchange was not impaired by the modification. However, the phosphorylated factor showed a marked reduction in the second-order rate constant, suggesting that the phosphorylation interfered with ribosome.eEF-2 complex formation by reducing the affinity of eEF-2 for the ribosome. This assumption was confirmed by direct measurements of the dissociation constants for the ribosomal complexes containing unmodified and phosphorylated eEF-2.
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Affiliation(s)
- U Carlberg
- Department of Cell Biology, Wenner-Gren Institute, University of Stockholm, Sweden
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36
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Davydova EK, Ovchinnikov LP. ADP-ribosylated elongation factor 2 (ADP-ribosyl-EF-2) is unable to promote translocation within the ribosome. FEBS Lett 1990; 261:350-2. [PMID: 2311763 DOI: 10.1016/0014-5793(90)80589-b] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Elongation factor 2 (EF-2), ADP-ribosylated in vitro by the A-fragment of diphtheria toxin, can (in the presence of GMPPCP) form stable complexes with ribosomes regardless of whether the ribosomes are empty or carrying poly(U) and Phe-tRNA in the A-site. Despite its efficient binding to ribosomes, ADP-ribosyl-EF-2, in contrast to the non-modified EF-2 is unable to promote the shift of Phe-tRNA from the A-site to the P-site of the ribosome as determined by the puromycin reaction, i.e. it is incapable of promoting the translocation reaction within the ribosome.
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Affiliation(s)
- E K Davydova
- Institute of Protein Research, Academy of Sciences of the USSR, Pushchino, Moscow Region
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37
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Simpson LL. Targeting drugs and toxins to the brain: magic bullets. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1988; 30:123-47. [PMID: 3061967 DOI: 10.1016/s0074-7742(08)60048-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- L L Simpson
- Department of Medicine, Jefferson Medical College, Philadelphia, Pennsylvania 19107
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38
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Simpson LL, Stiles BG, Zepeda HH, Wilkins TD. Molecular basis for the pathological actions of Clostridium perfringens iota toxin. Infect Immun 1987; 55:118-22. [PMID: 2878881 PMCID: PMC260288 DOI: 10.1128/iai.55.1.118-122.1987] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Clostridium perfringens type E iota toxin is composed of two separate and independent polypeptide chains that act synergistically in mouse lethal assays. The light chain is an enzyme that mono(ADP-ribosyl)ates certain amino acids. The enzyme displays substantial activity when homopoly-L-arginine is used as a substrate, but it shows little activity when polyasparagine, polylysine or polyglutamic acid are used. In keeping with the properties of an ADP-ribosylating enzyme, the toxin possesses the following characteristics. It produces incorporation of radioactivity into polyarginine when adenine-labeled NAD is used, but radioactivity is not incorporated when nicotinamide-labeled NAD is used. Irrespective of labeling, enzymatic activity is accompanied by the release of free nicotinamide. After incorporation of ADP-ribose groups into polyarginine, enzymatic and chemical techniques can be used to release the incorporated material. Snake venom phosphodiesterase releases mainly AMP; hydroxylamine releases AMP and ADP-ribose. The heavy chain of iota toxin has little or no enzyme activity, and it does not substantially affect the enzyme activity of the light chain. The heavy chain may be a binding component that directs the toxin to vulnerable cells. The data suggest that iota toxin is a representative of a novel class of ADP-ribosylating toxins.
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39
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Comments on the letter to the editor by Montecucco. Toxicon 1987. [DOI: 10.1016/0041-0101(87)90003-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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40
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Nilsson L, Nygård O. The mechanism of the protein-synthesis elongation cycle in eukaryotes. Effect of ricin on the ribosomal interaction with elongation factors. EUROPEAN JOURNAL OF BIOCHEMISTRY 1986; 161:111-7. [PMID: 3780730 DOI: 10.1111/j.1432-1033.1986.tb10130.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The functional significance of the post-translocation interaction of eukaryotic ribosomes with EF-2 was studied using the translational inhibitor ricin. Ribosomes treated with ricin showed a decreased rate of elongation accompanied by altered proportions of the different ribosomal phases of the elongation cycle. The content of ribosome-bound EF-2 was diminished by approximately 65% while that of EF-1 was unaffected. The markedly reduced content of EF-2 was caused by an inability of the ricin-treated ribosomes to form high-affinity pre-translocation complexes with EF-2. However, the ribosomes were still able to interact with EF-2 in the form of a low-affinity post-translocation complex. Ricin-treated ribosomes showed an altered ability to stimulate the GTP hydrolysis catalysed by either EF-1 or EF-2. The EF-1-catalysed hydrolysis was reduced by approximately 70%, resulting in a decreased turnover of the quaternary EF-1 X GTP X aminoacyl-tRNA X ribosome complex. In contrast, the EF-2-catalysed hydrolysis was increased by more than 400%, despite the lack of pre-translocation complex formation. The effect was not restricted to empty reconstituted ribosomes since gently salt-washed polysomes also showed an increased rate of GTP hydrolysis. The results indicate that the EF-1- and EF-2-dependent hydrolysis of GTP was activated by a common center on the ribosome that was specifically adapted for promoting the GTP hydrolysis of either EF-1 or EF-2. Furthermore, the results suggest that the GTP hydrolysis catalysed by EF-2 occurred in the low-affinity post-translocation complex.
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41
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Pertussis toxin-catalyzed ADP-ribosylation of transducin. Cysteine 347 is the ADP-ribose acceptor site. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)38585-x] [Citation(s) in RCA: 340] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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42
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Nilsson L, Nygård O. Localization of the sites of ADP-ribosylation and GTP binding in the eukaryotic elongation factor EF-2. EUROPEAN JOURNAL OF BIOCHEMISTRY 1985; 148:299-304. [PMID: 3987690 DOI: 10.1111/j.1432-1033.1985.tb08839.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Tryptic cleavage of EF-2, molecular mass 93 kDa, produced an 82-kDa polypeptide and a 10-kDa fragment, which was further degraded. By a slower reaction the 82-kDa polypeptide was gradually split into a 48-kDa and a 34-kDa fragment. Similarly, treatment with chymotrypsin resulted in the formation of an 82-kDa polypeptide and a small fragment. In contrast to the tryptic 82-kDa polypeptide the corresponding chymotryptic cleavage product was relatively resistant to further attack. The degradation of the 82-kDa polypeptide with either trypsin or chymotrypsin was facilitated by the presence of guanosine nucleotides, indicating a conformational shift in native EF-2 upon nucleotide binding. No effect was observed in the presence of ATP, indicating that the effect was specific for guanosine nucleotides. After affinity labelling of native EF-2 with oxidized [3H]GTP and subsequent trypsin treatment the radioactivity was recovered in the 48-kDa polypeptide showing that the GTP-binding site was located within this part of the factor. Correspondingly, tryptic degradation of EF-2 labelled with [14C]NAD+ in the presence of diphtheria toxin showed that the site of ADP-ribosylation was within the 34-kDa polypeptide. By cleavage with the tryptophan-specific reagent N-chlorosuccinimide the site of ADP-ribosylation could be located at a distance of 40-60 kDa from the GTP-binding site and about 4-11 kDa from the nearest terminus.
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Nygård O, Nilsson L. Reduced ribosomal binding of eukaryotic elongation factor 2 following ADP-ribosylation. Difference in binding selectivity between polyribosomes and reconstituted monoribosomes. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 824:152-62. [PMID: 3970930 DOI: 10.1016/0167-4781(85)90092-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The biological activity of elongation factor 2 (EF-2) following NAD+ - and diphtheria-toxin-dependent ADP-ribosylation was studied (i) in translation experiments using the reticulocyte lysate system and (ii) in ribosomal binding experiments using either reconstituted empty rat liver ribosomes or programmed reticulocyte polysomes. Treatment of the lysates with toxin and NAD+ at a NAD+/ribosome ratio of 4 resulted in a 90% inhibition of the amino acid incorporation rate. The inhibition was overcome by the addition of native EF-2. At this level of inhibition more than 90% of the EF-2 present in the lysates was ADP-ribosylated and the total ribosome association of EF-2 was reduced by approx. 50%. All of the remaining unmodified factor molecules were associated with the ribosomes, whereas only about 3% of the ribosylated factor was ribosome-associated. The nucleotide requirement for the binding of EF-2 to empty reconstituted rat liver ribosomes and programmed reticulocyte polysomes was studied together with the stability of the resulting EF-2 X ribosome complexes using purified 125I-labelled rat liver EF-2. With both types of ribosomes, the complex formation was strictly nucleotide-dependent. Stable, high-affinity complexes were formed in the presence of the non-hydrolysable GTP analogue guanosine 5'-(beta, gamma-methylene)triphosphate (GuoPP[CH2]P). In contrast to the reconstituted ribosomes, GTP stimulated the formation of high-affinity complexes in the presence of polysomes, albeit at a lower efficiency than GuoPP[CH2]P. The formation of high-affinity complexes was restricted to polysomes in the pretranslocation phase of the elongation cycle. Low-affinity post-translocation complexes, demonstrable after fixation, were formed in the presence of GTP, GuoPP[CH2]P and GDP. In polysomes, these complexes involved a different population of particles than did the high-affinity complexes. In the binding experiments using reconstituted or programmed ribosomes, the pretranslocation binding of EF-2 observed in the presence of GuoPP[CH2]P was reduced by approx. 50% after ADP-ribosylation, whereas the post-translocation binding in the presence of GDP was unaltered. The data indicate that the inhibition of translocation caused by diphtheria toxin and NAD+ is mediated through a reduced affinity of the ADP-ribosylated EF-2 for binding to ribosomes in the pretranslocation state.
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Nygård O, Nilsson L. Quantification of the different ribosomal phases during the translational elongation cycle in rabbit reticulocyte lysates. ACTA ACUST UNITED AC 1985; 145:345-50. [PMID: 6568179 DOI: 10.1111/j.1432-1033.1984.tb08560.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The proportionality of different ribosomal phases during elongation was estimated in the highly effective rabbit reticulocyte lysate system by use of several complementary analytical methods. The stoichiometric amounts of ribosome-bound elongation factors EF-1 and EF-2 were determined as a measure of ribosomal A-site occupation. The results were correlated with the puromycin reactivity of the P-site-located nascent polypeptide chains. Approximately 25% of the ribosomes were associated with EF-2, indicating that their A-sites contained peptidyl-tRNA. About 35% were associated with EF-1, signifying that their A-sites were occupied by aminoacyl-tRNA. The puromycin reactivity of the nascent chains was approximately 40%. From these data it is concluded that 75% of the peptidyl-tRNAs were located in the P-sites and that their puromycin reactivity was limited by the availability of ribosomal A-sites free for puromycin interaction. After guanosine 5'-[beta, gamma-methylene]triphosphate blockage of the translation, the ribosomal content of elongation factors drastically changed. Under these conditions the proportion of EF-1-containing ribosomes increased to approximately 50% while EF-2-containing ribosomes decreased to 5%. Concomitantly, the puromycin reactivity increased to approximately 45%. In contrast to previous assumptions the experiments support the view that the elongation rate is limited by the availability of ribosomal A-sites for the selection of mRNA-cognate aminoacyl-tRNAs.
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45
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46
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Yoshikawa A, Takano-Ohmuro H, Masaki T. Increase in the amount of elongation factor 2 in chicken muscular dystrophy. Muscle Nerve 1984; 7:733-40. [PMID: 6543921 DOI: 10.1002/mus.880070907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The amount of elongation factor 2 (EF2) in the cytoplasm and ribosome of breast muscle cell from normal and dystrophic strains of chicken was measured. Concentration in the cytoplasm of 20-day-old embryonic dystrophic muscle was higher than that in normal muscle, but no difference in content was found in muscles of 15-day-old embryos. The amount of EF2 bound to ribosomes was identical in normal and dystrophic muscles during all stages of development. Peptide mapping patterns of partial proteolytic fragments of EF2 from normal and dystrophic chicken breast muscles were similar. The increase in cytoplasmic protein synthetic activity of dystrophic breast muscles reported previously seems to be due to the corresponding increase in the number of EF2 molecules rather than to their modification in dystrophic muscle.
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47
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Zucker DR, Murphy JR, Pappenheimer AM. Monoclonal antibody analysis of diphtheria toxin--II. Inhibition of ADP-ribosyl-transferase activity. Mol Immunol 1984; 21:795-800. [PMID: 6207426 DOI: 10.1016/0161-5890(84)90166-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Monoclonal antibodies directed against the enzymatically active A-fragment of diphtheria toxin were used to investigate further the structure-function relationships within fragment A. Of 16 such antibodies, all but two were directed against epitopes located within the carboxy-terminal 30-40 amino acids of fragment A. Interestingly, the antibodies recognize several epitopes in this small region and varied considerably in their effects on toxin functions. With regard to their effects on the enzymatic activity of fragment A, three types of antibodies were found: (1) antibodies which bind fragment A but fail to inhibit its ADP-ribosyltransferase activity, (2) antibodies which completely inhibit enzyme activity, and (3) antibodies which interact with fragment A to yield antigen-antibody complexes of diminished activity. The results are consistent with location of the catalytic center of fragment A within its carboxy-terminal ca 4000 dalton region.
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48
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Momii A, Koide SS. Adenosine diphosphate-ribosyltransferase activity in permeabilized mouse testicular cells. Arch Biochem Biophys 1982; 214:628-33. [PMID: 6284033 DOI: 10.1016/0003-9861(82)90068-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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49
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Mandel P, Okazaki H, Niedergang C. Poly(adenosine diphosphate ribose). PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1982; 27:1-51. [PMID: 6285417 DOI: 10.1016/s0079-6603(08)60596-6] [Citation(s) in RCA: 122] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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50
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Prevention by nicotinamide of desensitization to thyrotropin stimulation in cultured human thyroid cells. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69923-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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