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Li Y, Zhou H, Chen S, Li Y, Guo Y, Chen X, Wang S, Wang L, Gan Y, Zhang S, Zheng Y, Sheng J, Zhou Z, Wang R. Bioorthogonal labeling and profiling of N6-isopentenyladenosine (i6A) modified RNA. Nucleic Acids Res 2024; 52:2808-2820. [PMID: 38426933 PMCID: PMC11014277 DOI: 10.1093/nar/gkae150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 02/06/2024] [Accepted: 02/16/2024] [Indexed: 03/02/2024] Open
Abstract
Chemical modifications in RNAs play crucial roles in diversifying their structures and regulating numerous biochemical processes. Since the 1990s, several hydrophobic prenyl-modifications have been discovered in various RNAs. Prenyl groups serve as precursors for terpenes and many other biological molecules. The processes of prenylation in different macromolecules have been extensively studied. We introduce here a novel chemical biology toolkit that not only labels i6A, a prenyl-modified RNA residue, by leveraging the unique reactivity of the prenyl group, but also provides a general strategy to incorporate fluorescence functionalities into RNAs for molecular tracking purposes. Our findings revealed that iodine-mediated cyclization reactions of the prenyl group occur rapidly, transforming i6A from a hydrogen-bond acceptor to a donor. Based on this reactivity, we developed an Iodine-Mediated Cyclization and Reverse Transcription (IMCRT) tRNA-seq method, which can profile all nine endogenous tRNAs containing i6A residues in Saccharomyces cerevisiae with single-base resolution. Furthermore, under stress conditions, we observed a decline in i6A levels in budding yeast, accompanied by significant decrease of mutation rate at A37 position. Thus, the IMCRT tRNA-seq method not only permits semi-quantification of i6A levels in tRNAs but also holds potential for transcriptome-wide detection and analysis of various RNA species containing i6A modifications.
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Affiliation(s)
- Yuanyuan Li
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Hongling Zhou
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Shasha Chen
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yinan Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yuyang Guo
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Xiaoqian Chen
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Sheng Wang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Li Wang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Youfang Gan
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Shusheng Zhang
- Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Ya Ying Zheng
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Jia Sheng
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Zhipeng Zhou
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Rui Wang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, Guangdong 518057, China
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Tarkowská D, Strnad M. Plant ecdysteroids: plant sterols with intriguing distributions, biological effects and relations to plant hormones. PLANTA 2016; 244:545-555. [PMID: 27339274 DOI: 10.1007/s00425-016-2561-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/18/2016] [Indexed: 06/06/2023]
Abstract
The present review summarises current knowledge of phytoecdysteroids' biosynthesis, distribution within plants, biological importance and relations to plant hormones. Plant ecdysteroids (phytoecdysteroids) are natural polyhydroxylated compounds that have a four-ringed skeleton, usually composed of either 27 carbon atoms or 28-29 carbon atoms (biosynthetically derived from cholesterol or other plant sterols, respectively). Their physiological roles in plants have not yet been confirmed and their occurrence is not universal. Nevertheless, they are present at high concentrations in various plant species, including commonly consumed vegetables, and have a broad spectrum of pharmacological and medicinal properties in mammals, including hepatoprotective and hypoglycaemic effects, and anabolic effects on skeletal muscle, without androgenic side-effects. Furthermore, phytoecdysteroids can enhance stress resistance by promoting vitality and enhancing physical performance; thus, they are considered adaptogens. This review summarises current knowledge of phytoecdysteroids' biosynthesis, distribution within plants, biological importance and relations to plant hormones.
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Affiliation(s)
- Danuše Tarkowská
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany AS CR, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic.
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany AS CR, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
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Ciaglia E, Pisanti S, Picardi P, Laezza C, Sosa S, Tubaro A, Vitale M, Gazzerro P, Malfitano AM, Bifulco M. N6-isopentenyladenosine affects cytotoxic activity and cytokines production by IL-2 activated NK cells and exerts topical anti-inflammatory activity in mice. Pharmacol Res 2014; 89:1-10. [PMID: 25063359 DOI: 10.1016/j.phrs.2014.07.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/10/2014] [Accepted: 07/14/2014] [Indexed: 01/13/2023]
Abstract
N6-isopentenyladenosine (iPA) is a modified adenosine with an isopentenyl moiety derived from the mevalonate pathway which displays pleiotropic biological effects, including anti-tumor and anti-angiogenic activity. Previous evidence revealed a biphasic effect of iPA on phytohemagglutinin-stimulated lymphocytes, being pro-proliferative at low doses and anti-proliferative at high doses. Analogously, we have recently shown that low iPA concentrations (<1μM) increased the immune response of natural killer (NK) cells against cancer targets. In the present study, we evaluated the effect of iPA at high concentration (10μM) on IL-2-activated NK cells. iPA, inhibited NK cell proliferation and cytotoxicity against their conventional tumor target, human K562 cells. This inhibition was associated with decreased expression and functionality of NK cell activating receptors NKp44 and NKG2D as well as impaired cyto/chemokines secretion (RANTES, MIP-1α, TNF-α and IFN-γ). ERK/MAPK and STAT5 activation in IL-2-activated NK cells were inhibited by iPA. The results obtained in vitro were validated in vivo in the inflammatory murine model of croton oil-induced ear dermatitis. The topical application of iPA significantly reduced mouse ear oedema, thus suggesting anti-inflammatory properties of this molecule. These results show the ability of iPA to exert anti-inflammatory effects both in vitro and in vivo directly targeting NK cells, providing a novel pharmacological tool in those diseases characterized by a deregulated immune-response, such as cancer or inflammatory conditions.
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Affiliation(s)
- Elena Ciaglia
- Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende, 84081 Baronissi, Salerno, Italy; Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Salerno, Italy.
| | - Simona Pisanti
- Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende, 84081 Baronissi, Salerno, Italy; Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Salerno, Italy
| | - Paola Picardi
- Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende, 84081 Baronissi, Salerno, Italy; Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Salerno, Italy
| | - Chiara Laezza
- Institute of Endocrinology and Experimental Oncology, IEOS CNR, Via Pansini 5, 80131 Naples, Italy; Department of Biology and Cellular and Molecular Pathology, University of Naples Federico II, Via Pansini, 80131 Naples, Italy
| | - Silvio Sosa
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
| | - Aurelia Tubaro
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
| | - Mario Vitale
- Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende, 84081 Baronissi, Salerno, Italy
| | - Patrizia Gazzerro
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Salerno, Italy
| | - Anna Maria Malfitano
- Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende, 84081 Baronissi, Salerno, Italy; Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Salerno, Italy
| | - Maurizio Bifulco
- Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende, 84081 Baronissi, Salerno, Italy; Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Salerno, Italy.
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Pisanti S, Picardi P, Ciaglia E, Margarucci L, Ronca R, Giacomini A, Malfitano AM, Casapullo A, Laezza C, Gazzerro P, Bifulco M. Antiangiogenic effects of N6-isopentenyladenosine, an endogenous isoprenoid end product, mediated by AMPK activation. FASEB J 2013; 28:1132-44. [PMID: 24265487 DOI: 10.1096/fj.13-238238] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
N6-isopentenyladenosine (iPA), an end product of the mevalonate pathway with an isopentenyl chain, is already known to exert a suppressor effect against various tumors. In this work, we investigated whether iPA also directly interferes with the angiogenic process, which is fundamental to tumor growth and progression. To this end, using human umbilical vein endothelial cells (HUVECs) as a suitable in vitro model of angiogenesis, we evaluated their viability, proliferation, migration, invasion, tube formation in response to iPA, and molecular mechanisms involved. Data were corroborated in mice by using a gel plug assay. iPA dose- and time-dependently inhibited all the neoangiogenesis stages, with an IC50 of 0.98 μM. We demonstrated for the first time, by liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS), that iPA was monophosphorylated into 5'-iPA-monophosphate (iPAMP) by the adenosine kinase (ADK) inside the cells. iPAMP is the active form that inhibits angiogenesis through the direct activation of AMP-kinase (AMPK). Indeed, all effects were completely reversed by pretreatment with 5-iodotubercidin (5-Itu), an ADK inhibitor. The isoprenoid intermediate isopentenyl pyrophosphate (IPP), which shares the isopentenyl moiety with iPA, was ineffective in the inhibition of angiogenesis, thus showing that the iPA structure is specific for the observed effects. In conclusion, iPA is a novel AMPK activator and could represent a useful tool for the treatment of diseases where excessive neoangiogenesis is the underlying pathology.
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Affiliation(s)
- Simona Pisanti
- 2University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Salerno, Italy. S.P.,
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Ottria R, Casati S, Baldoli E, Maier JA, Ciuffreda P. N6-Alkyladenosines: Synthesis and evaluation of in vitro anticancer activity. Bioorg Med Chem 2010; 18:8396-402. [DOI: 10.1016/j.bmc.2010.09.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 09/06/2010] [Accepted: 09/14/2010] [Indexed: 01/08/2023]
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Ottria R, Casati S, Maier JAM, Mariotti M, Ciuffreda P. Novel isopentenyladenosine analogues: synthesis, characterization, and evaluation of antiproliferative activity on bladder carcinoma cells. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2010; 28:736-51. [PMID: 20183613 DOI: 10.1080/15257770903155550] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Isopentenyladenosine (iPA), a member of the cytokinin family of plant hormones, exerts a marked antiproliferative activity on some leukemic and epithelial cancer cell lines. To characterize the molecular moieties required for the in vitro antitumor activity of the molecule and to obtain cytostatic iPA derivatives potentially useful as chemotherapeutic agents, N9-acyclic analogues have been synthesized using regioselective Mitsunobu reaction and characterized by elemental analyses, (1)H and (13)C NMR. These compounds were analyzed for their activity on human bladder cancer cell lines. In this study, we report that iPA inhibited the proliferation but not the migration of human bladder cancer cells, while the newly synthesized analogues revealed no significant cytostatic activity apart from the compound with a saturated double bond of the isopentenyl chain. These results indicate that the integrity of the ribose ring is required for the cytostatic activity of iPA.
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Affiliation(s)
- Roberta Ottria
- Dipartimento di Scienze Precliniche LITA Vialba-Universita degli Studi di Milano, Milano, Italy
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7
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Laezza C, Notarnicola M, Caruso MG, Messa C, Macchia M, Bertini S, Minutolo F, Portella G, Fiorentino L, Stingo S, Bifulco M. N6‐isopentenyladenosine arrests tumor cell proliferation by inhibiting farnesyl diphosphate synthase and protein prenylation. FASEB J 2006; 20:412-8. [PMID: 16507758 DOI: 10.1096/fj.05-4044lsf] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The physiological effects of a variety of N6-substituted adenine and adenosine derivatives called cytokinins have been documented in plants, but information on their occurrence and function in other biological system is limited. Here we investigated the anti-proliferative effect of N6-isopentenyladenosine (i6A), an adenosine and isoprenoid derivative, in a thyroid cell system, FRTL-5 wild-type, and K-ras transformed KiMol cells. Addition of i6A to FRTL-5 cells caused a dose-dependent arrest of the G0-G1 cell phase transition associated with a reduction of cells in the S phase that was much more evident in KiMol cells. I6A arrested tumor cell proliferation by inhibiting farnesyl diphosphate synthase (FPPS) and protein prenylation. Indeed the addition of farnesol reversed these effects and i6A affected protein prenylation, in particular lamin B processing. I6A effect was not mediated by the adenosine receptor but was due to a direct modulation of FPPS enzyme activity as a result of its uptake inside the cells. I6A inhibited FPPS activity more efficaciously in KiMol cells than in normal FRTL-5. Moreover, the i6A anti-proliferative effect was evaluated in vivo in a nude mouse xenograft model, where KiMol cells were implanted subcutaneously. Mice treated with i6A showed a drastic reduction in tumor volume. Our findings indicate that this isoprenoid end product might be used for antineoplastic therapy, an application emulating that of the lovastatin and/or farnesyl-transferase inhibitors
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Affiliation(s)
- Chiara Laezza
- Istituto di Endocrinologia e Oncologia Sperimentale. I.E.O.S., CNR, Bari, Italy.
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8
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Hemmerlin A, Gerber E, Feldtrauer JF, Wentzinger L, Hartmann MA, Tritsch D, Hoeffler JF, Rohmer M, Bach TJ. A review of tobacco BY-2 cells as an excellent system to study the synthesis and function of sterols and other isoprenoids. Lipids 2004; 39:723-35. [PMID: 15638240 DOI: 10.1007/s11745-004-1289-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In plants, two pathways are utilized for the synthesis of isopentenyl diphosphate (IPP), the universal precursor for isoprenoid biosynthesis. In this paper we review findings and observations made primarily with tobacco BY-2 cells (TBY-2), which have proven to be an excellent system in which to study the two biosynthetic pathways. A major advantage of these cells as an experimental system is their ability to readily take up specific inhibitors and stably- and/or radiolabeled precursors. This permits the functional elucidation of the role of isoprenoid end products and intermediates. Because TBY-2 cells undergo rapid cell division and can be synchronized within the cell cycle, they constitute a highly suitable test system for determination of those isoprenoids and intermediates that act as cell cycle inhibitors, thus giving an indication of which branches of the isoprenoid pathway are essential. Through chemical complementation; and use of precursors, intracellular compartmentation can be elucidated, as well as the extent to which the plastidial and cytosolic pathways contribute to the syntheses of specific groups of isoprenoids (e.g., sterols) via exchange of intermediates across membranes. These topics are discussed in the context of the pertinent literature.
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Affiliation(s)
- Andréa Hemmerlin
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (UPR 2357), Département Fonctions et Biosynthèse des Isoprénoïdes, Université Louis Pasteur, F-67083 Strasbourg, France
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9
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Ciccarelli R, Ballerini P, Sabatino G, Rathbone MP, D'Onofrio M, Caciagli F, Di Iorio P. Involvement of astrocytes in purine‐mediated reparative processes in the brain. Int J Dev Neurosci 2001; 19:395-414. [PMID: 11378300 DOI: 10.1016/s0736-5748(00)00084-8] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Astrocytes are involved in multiple brain functions in physiological conditions, participating in neuronal development, synaptic activity and homeostatic control of the extracellular environment. They also actively participate in the processes triggered by brain injuries, aimed at limiting and repairing brain damages. Purines may play a significant role in the pathophysiology of numerous acute and chronic disorders of the central nervous system (CNS). Astrocytes are the main source of cerebral purines. They release either adenine-based purines, e.g. adenosine and adenosine triphosphate, or guanine-based purines, e.g. guanosine and guanosine triphosphate, in physiological conditions and release even more of these purines in pathological conditions. Astrocytes express several receptor subtypes of P1 and P2 types for adenine-based purines. Receptors for guanine-based purines are being characterised. Specific ecto-enzymes such as nucleotidases, adenosine deaminase and, likely, purine nucleoside phosphorylase, metabolise both adenine- and guanine-based purines after release from astrocytes. This regulates the effects of nucleotides and nucleosides by reducing their interaction with specific membrane binding sites. Adenine-based nucleotides stimulate astrocyte proliferation by a P2-mediated increase in intracellular [Ca2+] and isoprenylated proteins. Adenosine also, via A2 receptors, may stimulate astrocyte proliferation, but mostly, via A1 and/or A3 receptors, inhibits astrocyte proliferation, thus controlling the excessive reactive astrogliosis triggered by P2 receptors. The activation of A1 receptors also stimulates astrocytes to produce trophic factors, such as nerve growth factor, S100beta protein and transforming growth factor beta, which contribute to protect neurons against injuries. Guanosine stimulates the output of adenine-based purines from astrocytes and in addition it directly triggers these cells to proliferate and to produce large amount of neuroprotective factors. These data indicate that adenine- and guanine-based purines released in large amounts from injured or dying cells of CNS may act as signals to initiate brain repair mechanisms widely involving astrocytes.
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Affiliation(s)
- R Ciccarelli
- Department of Biomedical Sciences, Section of Pharmacology, Via del Vestini Pal. B, 66013, Chieti, Italy.
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Warner GJ, Berry MJ, Moustafa ME, Carlson BA, Hatfield DL, Faust JR. Inhibition of selenoprotein synthesis by selenocysteine tRNA[Ser]Sec lacking isopentenyladenosine. J Biol Chem 2000; 275:28110-9. [PMID: 10821829 DOI: 10.1074/jbc.m001280200] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A common posttranscriptional modification of tRNA is the isopentenylation of adenosine at position 37, creating isopentenyladenosine (i(6)A). The role of this modified nucleoside in protein synthesis of higher eukaryotes is not well understood. Selenocysteyl (Sec) tRNA (tRNA([Ser]Sec)) decodes specific UGA codons and contains i(6)A. To address the role of the modified nucleoside in this tRNA, we constructed a site-specific mutation, which eliminates the site of isopentenylation, in the Xenopus tRNA([Ser]Sec) gene. Transfection of the mutant tRNA([Ser]Sec) gene resulted in 80% and 95% reduction in the expression of co-transfected selenoprotein genes encoding type I and II iodothyronine deiodinases, respectively. A similar decrease in type I deiodinase synthesis was observed when transfected cells were treated with lovastatin, an inhibitor of the biosynthesis of the isopentenyl moiety. Neither co-transfection with the mutant tRNA gene nor lovastatin treatment reduced type I deiodinase mRNA levels. Also, mutant tRNA expression did not alter initiation of translation or degradation of the type I deiodinase protein. Furthermore, isopentenylation of tRNA([Ser]Sec) was not required for synthesis of Sec on the tRNA. We conclude that isopentenylation of tRNA([Ser]Sec) is required for efficient translational decoding of UGA and synthesis of selenoproteins.
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Affiliation(s)
- G J Warner
- Tufts University School of Medicine, Department of Physiology, Boston, Massachusetts 02111, USA
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Martínez-Botas J, Suárez Y, Ferruelo AJ, Gómez-Coronado D, Lasuncion MA. Cholesterol starvation decreases p34(cdc2) kinase activity and arrests the cell cycle at G2. FASEB J 1999; 13:1359-70. [PMID: 10428760 DOI: 10.1096/fasebj.13.11.1359] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
As a major component of mammalian cell plasma membranes, cholesterol is essential for cell growth. Accordingly, the restriction of cholesterol provision has been shown to result in cell proliferation inhibition. We explored the potential regulatory role of cholesterol on cell cycle progression. MOLT-4 and HL-60 cell lines were cultured in a cholesterol-deficient medium and simultaneously exposed to SKF 104976, which is a specific inhibitor of lanosterol 14-alpha demethylase. Through HPLC analyses with on-line radioactivity detection, we found that SKF 104976 efficiently blocked the [(14)C]-acetate incorporation into cholesterol, resulting in an accumulation of lanosterol and dihydrolanosterol, without affecting the synthesis of mevalonic acid. The inhibitor also produced a rapid and intense inhibition of cell proliferation (IC(50) = 0.1 microM), as assessed by both [(3)H]-thymidine incorporation into DNA and cell counting. Flow cytometry and morphological examination showed that treatment with SKF 104976 for 48 h or longer resulted in the accumulation of cells specifically at G2 phase, whereas both the G1 traversal and the transition through S were unaffected. The G2 arrest was accompanied by an increase in the hyperphosphorylated form of p34(cdc2) and a reduction of its activity, as determined by assaying the H1 histone phosphorylating activity of p34(cdc2) immunoprecipitates. The persistent deficiency of cholesterol induced apoptosis. However, supplementing the medium with cholesterol, either in the form of LDL or free cholesterol dissolved in ethanol, completely abolished these effects, whereas mevalonate was ineffective. Caffeine, which abrogates the G2 checkpoint by preventing p34(cdc2) phosphorylation, reduced the accumulation in G2 when added to cultures containing cells on transit to G2, but was ineffective in cells arrested at G2 by sustained cholesterol starvation. Cells arrested in G2, however, were still viable and responded to cholesterol provision by activating p34(cdc2) and resuming the cell cycle. We conclude that in both lymphoblastoid and promyelocytic cells, cholesterol availability governs the G2 traversal, probably by affecting p34(cdc2) activity.
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Affiliation(s)
- J Martínez-Botas
- Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, 28034 Madrid, Spain
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Abstract
Farnesyl protein transferase (FPT) activity was measured in rat liver subcellular fractions by using an unspecific acceptor for the farnesyl groups. The highest specific activity was found in mitochondria and it exceeded that of the microsomes three-fold. Considerably lower specific activities were found in the nuclei and cytosol. Further subfractionation revealed that the mitochondrial FPT activity is located in the matrix. The beta-subunit of the mitochondrial enzyme has an apparent molecular mass of 46 kDa, which is similar to its cytosolic counterpart. The results suggest that protein farnesylation can take place in a number of subcellular organelles.
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Affiliation(s)
- J Grünler
- Department of Biochemistry, Stockholm University, Sweden
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Warner GJ, Rusconi CP, White IE, Faust JR. Identification and sequencing of two isopentenyladenosine-modified transfer RNAs from Chinese hamster ovary cells. Nucleic Acids Res 1998; 26:5533-5. [PMID: 9826781 PMCID: PMC147999 DOI: 10.1093/nar/26.23.5533] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To determine the presence and identity of isopentenyladenosine-containing transfer RNAs (tRNAs) in a mammalian cell line, we adopted a novel method to isolate, clone and sequence these RNAs. This method was based on 3' polyadenylation of the tRNA prior to cDNA synthesis, PCR amplification, cloning and DNA sequencing. Using this unique procedure, we report the cloning and sequencing of the selenocysteine-tRNA and mitochondrial tryptophan-tRNA from Chinese hamster ovary cells which contain this specific tRNA modification. This new method will be useful in the identification of other tRNAs and other small RNAs where the primary sequence is unknown.
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Affiliation(s)
- G J Warner
- Department of Physiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
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Martínez-Botas J, Ferruelo AJ, Suárez Y, Gómez-Coronado D, Lasunción MA. Induction of apoptosis in p53-null HL-60 cells by inhibition of lanosterol 14-alpha demethylase. Biochimie 1998; 80:887-94. [PMID: 9893947 DOI: 10.1016/s0300-9084(00)88884-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
To determine the role of cholesterol deprivation in cell proliferation and, eventually, in apoptosis, HL-60 promyelocytic cells were incubated in a cholesterol-depleted medium in the presence of SKF 104976, a specific inhibitor of lanosterol 14-alpha demethylase. As expected, SKF 104976 efficiently blocked the [14C]-acetate incorporation into cholesterol, whereas it induced the accumulation of both lanosterol and, especially, dihydrolanosterol. As a consequence, cell proliferation was greatly depressed at 24 h of treatment with the drug, and clear signs of apoptosis--annexin V binding, condensed and fragmented nuclei and DNA ladder--were observed thereafter. Provided that the HL-60 cell line does not express p53, it may be concluded that apoptosis induced by cholesterol deprivation is not dependent on this tumor suppressor protein. Supplementing the incubation medium with LDL-cholesterol or pure free cholesterol, fully prevented cell growth inhibition and apoptosis induction, whereas mevalonate was ineffective. These results indicate that cholesterol plays a specific role in cell proliferation, a function that is not shared by its precursors lanosterol and dihydrolanosterol.
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Affiliation(s)
- J Martínez-Botas
- Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, Madrid, Spain
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15
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Laezza C, Migliaro A, Cerbone R, Tedesco I, Santillo M, Garbi C, Bifulco M. N6-isopentenyladenosine affects cAMP-dependent microfilament organization in FRTL-5 thyroid cells. Exp Cell Res 1997; 234:178-82. [PMID: 9223384 DOI: 10.1006/excr.1997.3610] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
N6-Isopentenyladenosine (i6A), an adenosine and mevalonate derivative, inhibits, like adenosine, TSH-induced cAMP increase and its related events (I- uptake and DNA synthesis) in FRTL-5 cells. This inhibition is dose-dependent and is measurable at 10(-8) M. However, unlike adenosine, i6A prevents TSH-promoted microfilament disassembly. The effect of i6A on cytoskeletal structure is antagonized by pertussis toxin and could be assigned to its N6 substitution since it can be mimicked by other synthetic N6-adenosine derivatives. It is suggested that a step beyond cAMP is involved, since i6A prevents also microfilament disassembly induced by 8-bromo-cAMP. This is the first demonstration that an adenosine derivative, which is also an end-product of the isoprenoid pathway, affects cAMP-dependent microfilament organization.
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Affiliation(s)
- C Laezza
- Centro di Endocrinologia ed Oncologia Sperimentale del CNR, Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università di Napoli Federico II, Naples, Italy
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16
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Affiliation(s)
- O Larsson
- Department of Tumor Pathology, Karolinska Institute, S-171 77 Stockholm, Sweden
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17
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Laten HM. Cytokinins affect spore formation but not cell division in the yeast Saccharomyces cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1266:45-9. [PMID: 7718620 DOI: 10.1016/0167-4889(94)00214-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cytokinins are N6-substituted adenine derivatives that function as essential growth hormones in higher plants. In experimental systems, cytokinins can influence cell growth and differentiation among both plant and non-plant tissues. The single-celled yeast, Saccharomyces cerevisiae, has served as an effective and useful model system for the study of a wide range of cellular phenomena generally associated with higher eukaryotes, including mammals. In an attempt to assess the efficacy of its use to dissect the molecular basis for plant hormone action, the effects of cytokinins on S. cerevisiae with respect to cell division rates and sporulation efficiencies were monitored. While none of the cytokinins tested influenced mitotic generation times, micromolar concentrations of kinetin enhanced the formation of yeast haploid ascospores and even lower concentrations of isopentenyladenine inhibited ascus formation.
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Affiliation(s)
- H M Laten
- Department of Biology, Loyola University Chicago, Chicago, IL 60626, USA
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18
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Shipton CA, Parmryd I, Swiezewska E, Andersson B, Dallner G. Isoprenylation of plant proteins in vivo. Isoprenylated proteins are abundant in the mitochondria and nuclei of spinach. J Biol Chem 1995; 270:566-72. [PMID: 7822281 DOI: 10.1074/jbc.270.2.566] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Protein isoprenylation in vivo is demonstrated using spinach seedlings labeled with [3H]mevalonate. This report provides evidence for the occurrence of a large number of isoprenylated proteins in plants. Seedlings, without roots, were labeled quantitatively through the cut stem. Mevinolin treatment of the seedlings resulted in increased incorporation of radiolabel into proteins. Approximately 30 labeled bands could be detected after autoradiography of SDS-polyacrylamide gel electrophoresis-separated polypeptides, ranging in molecular mass from 6 to 200 kDa. Methyl iodide hydrolysis resulted in the release of covalently bound farnesol, geranylgeraniol, phytol, and some unidentified isoprenoid compounds from mevalonate-labeled proteins. It was found that all cellular fractions contained some isoprenylated proteins, although most were located in the mitochondria and nuclei. Subfractionation of the nucleus revealed that the majority of isoprenylated proteins in this compartment were components of the nuclear matrix. The results demonstrate that in vivo labeling of a complex organism can be performed using a plant system in order to study protein isoprenylation and distribution of modified proteins in different cellular compartments.
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Affiliation(s)
- C A Shipton
- Arrhenius Laboratories for Natural Sciences, Biochemistry Department, University of Stockholm, Sweden
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19
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Siperstein MD. Cholesterol, cholesterogenesis and cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 369:155-66. [PMID: 7598003 DOI: 10.1007/978-1-4615-1957-7_14] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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20
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Munro E, Patel M, Chan P, Betteridge L, Clunn G, Gallagher K, Hughes A, Schachter M, Wolfe J, Sever P. Inhibition of human vascular smooth muscle cell proliferation by lovastatin: the role of isoprenoid intermediates of cholesterol synthesis. Eur J Clin Invest 1994; 24:766-72. [PMID: 7890015 DOI: 10.1111/j.1365-2362.1994.tb01074.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Restenosis remains the largest single obstacle to the long-term success of invasive vascular interventions. Lovastatin, an HMG-CoA reductase inhibitor, has been shown to reduce myointimal hyperplasia in animal models of restenosis and in one clinical coronary restenosis trial. We have assessed the effect of lovastatin on the growth of cultured human vascular smooth muscle cells derived from saphenous vein and vascular graft stenoses. Lovastatin (2 microM) inhibited proliferation over 14 days in saphenous vein (and graft stenoses) derived vascular smooth muscle cells by 42% and 32% respectively: this was not significantly different. Lovastatin (10 microM) reduced [methyl 3H]-thymidine uptake by 51% in saphenous vein-derived cells. These concentrations were significantly higher than those achieved in plasma during therapeutic dosage. Lovastatin-induced inhibition of vascular smooth muscle cell proliferation and [methyl 3H]-thymidine uptake was completely reversed by adding mevalonate (100 microM) but cholesterol (10-40 micrograms ml-1) had no effect. Isopentenyl adenine (25-50 microM) did not affect the inhibition of [methyl 3H]-thymidine uptake by lovastatin (10 microM), but farnesol (20 microM), another isoprenoid precursor of cholesterol synthesis, reversed the antiproliferative effect.
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Affiliation(s)
- E Munro
- Department of Clinical Pharmacology, St Mary's Hospital Medical School, Imperial College of Science, Technology and Medicine, London, UK
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21
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Ura H, Obara T, Nishino N, Tanno S, Okamura K, Namiki M. Cytotoxicity of simvastatin to pancreatic adenocarcinoma cells containing mutant ras gene. Jpn J Cancer Res 1994; 85:633-8. [PMID: 8063617 PMCID: PMC5919528 DOI: 10.1111/j.1349-7006.1994.tb02406.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Simvastatin (SV), a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, inhibits the synthesis of mevalonic acid. The dose-dependent (0.1-100 micrograms/ml) cytotoxicity of SV towards human (MIAPaCa-2, Panc-1, HPC-1, HPC-3, HPC-4, PK-1, PK-9) and hamster (T2) pancreatic carcinoma cell lines was determined by MTT assay. At up to 20 micrograms/ml of SV, the effect was reversible and was restored by 60 micrograms/ml mevalonic acid. Point mutation of Ki-ras at codon 12 in each cell line was detected by means of the modified polymerase chain reaction. The concentration of SV necessary to achieve 50% cytotoxicity was about 10 micrograms/ml, and at this concentration of SV, DNA synthesis assayed in terms of [3H]thymidine uptake, isoprenylation of p21ras examined by Western blotting and cell progression from G1 to S phase of the cell cycle analyzed by flow cytometry were all inhibited. Isoprenylation inhibitors of p21ras, such as SV, are expected to be useful for the treatment of pancreatic cancer.
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Affiliation(s)
- H Ura
- Third Department of Internal Medicine, Asahikawa Medical College, Hokkaido
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22
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Wejde J, Carlberg M, Hjertman M, Larsson O. Isoprenoid regulation of cell growth: identification of mevalonate-labelled compounds inducing DNA synthesis in human breast cancer cells depleted of serum and mevalonate. J Cell Physiol 1993; 155:539-48. [PMID: 8491791 DOI: 10.1002/jcp.1041550312] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Growth arrest induced by serum depletion and/or treatment with mevinolin (an inhibitor of mevalonate synthesis) in the human breast cancer cell line Hs578T was overcome by exogenous mevalonate, indicating that some product or metabolite of mevalonate may be involved in the mediation of serum-regulated growth of these cells. In the search for such compounds we first tested a variety of known end products of mevalonate with respect to their ability to counteract the inhibition of DNA synthesis caused by serum-free medium and mevinolin. Thereby high doses (10 micrograms/ml) of dolichol-20 were found to cause a partial counteraction. After straight-phase HPLC purification of endogenous lipids, isolated from 3H- or 14C-mevalonate-labelled Hs578T cultures, we found that non-sterol lipids co-eluting with dolichols efficiently induced DNA synthesis. After further purification with reverse-phase HPLC it was confirmed that virtually all of this effect was achieved by compounds(s) (seen as a single UV and radioactive peak) co-eluting with dolichol-20. Nanogram doses, at most, of this (these) compound(s) elicited a substantial stimulation of DNA synthesis. The lipid(s) also counteracted the inhibition by mevinolin of N-linked glycosylation, indicating that it (they) also interfere(s) with this processing. Since treatment with tunicamycin (an inhibitor of N-linked glycosylation) abolished this growth-stimulative effect, N-linked glycosylation seems to be a necessary event in the processes leading to lipid-induced initiation of DNA synthesis.
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Affiliation(s)
- J Wejde
- Department of Tumor Pathology, Karolinska Institutet, Karolinska Hospital, Stockholm, Sweden
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23
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Mutations of the molecular chaperone protein SecB which alter the interaction between SecB and maltose-binding protein. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53894-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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24
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Havel CM, Fisher P, Watson JA. Isopentenoid synthesis in embryonic Drosophila cells: prenylated protein profile and prenyl group usage. Arch Biochem Biophys 1992; 295:410-20. [PMID: 1586169 DOI: 10.1016/0003-9861(92)90535-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It has been established that vertebrates and yeasts modified a unique subset of polypeptides with farnesyl and geranylgeranyl residues. This observation has been extended to Drosophila Kc cells. [3H]Mevalonate was incorporated into 54 Kc cell peptides (18-92 kDa). As reported for mammalian cells, most of the labeled peptides had molecular weights between 21 and 27 kDa. C18 radio-HPLC tryptic digest profiles for delipidized, [3H]mevalonate-labeled (a) insect (Drosophila and Spodoptera frugiperda) and mammalian (Chinese hamster ovary met 18-2b) cells, (b) Kc cell nuclear lamin, and (c) a 23.5-kDa purified Kc cell GTP-binding protein were compared and analyzed. [35S]Cysteine-labeled Kc cells yielded a tryptic digest radio-HPLC profile which was congruent with that for [3H]mevalonate-labeled cells. A significant fraction (30-33%) of the doubly labeled tryptic peptides were eluted with greater than or equal to 93% acetonitrile. Kc cell nuclear lamin tryptic digests yielded a single 3H-labeled product which migrated as S-farnesylcysteine. The Kc cell 23.5-kDa GTP-binding protein's 3H-labeled oligopeptide(s)/amino acid(s) was geranylgeranylated and its tryptic digest profile was representative of prenylated proteins whose oligopeptides eluted with greater than or equal to 93% acetonitrile. Moreover, the 3H-labeled oligopeptide/amino acid profiles plus prenyl group patterns for [3H]mevalonate-labeled Kc and mammalian cell total extracts were similar. Collectively, these observations supported a prenylated protein spectrum and prenyl group usage as highly conserved eukaryotic cellular characteristics.
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Affiliation(s)
- C M Havel
- Department of Biochemistry and Biophysics, University of California, San Francisco 94143
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