DOCSLIB.ORG

De Novo Fatty Acid Synthesis Is Required for Establishment of Cell Type-Specific Gene Transcription During Sporulation in Bacill

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
De Novo Fatty Acid Synthesis Is Required for Establishment of Cell Type-Specific Gene Transcription During Sporulation in Bacill Molecular Microbiology (1998) 29(5), 1215–1224 De novo fatty acid synthesis is required for establishment of cell type-specific gene transcription during sporulation in Bacillus subtilis Gustavo E. Schujman, Roberto Grau, Hugo C. compartment (Lutkenhaus, 1994). The unequal-sized pro- Gramajo, Leonardo Ornella and Diego de Mendoza* geny resulting from the formation of the polar septum Programa Multidisciplinario de Biologı´a Experimental have different developmental fates and express different (PROMUBIE) and Departamento de Microbiologı´a, sets of genes (for reviews see Errington, 1993; Losick Facultad de Ciencias Bioquı´micas y Farmace´uticas, and Stragier, 1996). The fate of the forespore chamber Universidad Nacional de Rosario, Suipacha 531, 2000- is determined by the transcription factor sF, which is pre- Rosario, Argentina. sent before the formation of the polar septum but does not become active in directing gene transcription until completion of asymmetric division, when its activity is con- Summary fined to the smaller compartment of the sporangium (for A hallmark of sporulation of Bacillus subtilis is the for- reviews see Losick and Stragier, 1996) mation of two distinct cells by an asymmetric septum. The activity of sF is regulated by a pathway consisting of The developmental programme of these two cells the proteins SpoIIAB, SpoIIAA and SpoIIE, all of which are involves the compartmentalized activities of sE in the produced before the formation of the polar septum (Duncan larger mother cell and of sF in the smaller prespore. and Losick, 1993; Min et al., 1993; Alper et al., 1994; Die- A potential role of de novo lipid synthesis on develop- derich et al., 1994; Arigoni et al., 1995; Duncan et al., ment was investigated by treating B. subtilis cells with 1995). SpoIIAB is an anti-sigma factor that binds to sF cerulenin, a specific inhibitor of fatty acid biosynth- and holds it in an inactive complex (Duncan and Losick, esis. These experiments demonstrated that spore for- 1993; Min et al., 1993; Magnin et al., 1996). SpoIIAA, on mation requires de novo fatty acid synthesis at the the other hand, is an anti-anti-sigma factor that binds to onset of sporulation. The transcription of the sporula- SpoIIAB, thereby causing the release of free and active tion genes that are induced before the formation of sF from the SpoIIAB–sF complex (Alper et al., 1994; Die- two cell types or that are under the exclusive control derich et al., 1994). SpoIIAB is also a protein kinase that of sF occurred in the absence of fatty acid synthesis, phosphorylates and thereby inactivates SpoIIAA (Min et as monitored by spo–lacZ fusions. However, expres- al., 1993). Finally, SpoIIE is a serine phosphatase that is sion of lacZ fusions to genes that required activation capable of dephosphorylating SpoIIAA-P, thereby restor- of sE for transcription was inhibited in the absence ing the ability of SpoIIAA to bind SpoIIAB (Duncan et al., of fatty acid synthesis. The block in sE-directed gene 1995; Arigoni et al., 1996; Feucht et al., 1996). Interest- expression in cerulenin-treated cells was caused by ingly, SpoIIE has an additional function beyond its role in an inability to process pro-sE to its active form. Elec- sF activation (Bara´k and Youngman, 1996; Feucht et tron microscopy revealed that these fatty acid-starved al., 1996). In its absence, but not in mutants specifically cells initiate abnormal polar septation, suggesting that affected in SpoIIE phosphatase activity, the sporulation de novo fatty acid synthesis may be essential to couple septum develops an aberrantly thick layer of peptidogly- the activation of the mother cell transcription factors can and the time of septum formation is delayed (Bara´k with the formation of the differentiating cells. and Youngman, 1996; Feucht et al., 1996); the later effect is attributed to an amino acid sequence at the extreme COOH-terminus of SpoIIE (Feucht et al., 1996). Thus, Introduction combination of these two functions in a single polypeptide A hallmark of the process of sporulation in the Gram- may serve to couple the release of the cell-specific tran- positive bacterium Bacillus subtilis is the formation of an scription factors with the formation of the differentiating asymmetrically positioned (polar) septum that divides the cells. cell into a small forespore compartment and a large cell Establishment of forespore specificity through activation of sF is soon followed by induction in the mother cell of Received 26 March, 1998; revised 1 June, 1998; accepted 5 June, 1998. *For correspondence. E-mail [email protected]; a large set of genes under the control of the transcription Tel. (41) 350 661; Fax (41) 390 465. factor sE (Losick and Stragier, 1996). sE is an unusual Q 1998 Blackwell Science Ltd 1216 G. E. Schujman et al. sigma factor in that it is synthesized as an inactive large synthesis and septation in B. subtilis (Strauch et al., 1992). precursor, pro-sE, the primary product of the promoter Moreover, it has recently been demonstrated that branched- distal member (spoIIGB ) of the two cistron spoIIG operon chain fatty acids play an important role in cell–cell com- (LaBell et al., 1987). Pro-sE is converted to its active form munication and development in Mixococcus xantus (Down- by proteolytic removal of its pro-amino acid sequence, an ward and Toal, 1995; Toal et al., 1995). N-terminal extension of 27 residues. The product of the In this report, we demonstrate that de novo fatty acid first gene of the operon, spoIIGA, is a multispanning mem- synthesis after the end of exponential phase is required brane protein that is sufficient for activation of pro-sE and for spore formation and that a reduced level of fatty acid that is believed to be the processing enzyme (Stragier et synthesis allows formation of asymmetric septa but pre- al., 1988). As both pro-sE and SpoIIGA are present before vents activation of sE. We speculate that septal membrane septation, and are presumably segregated into each of the lipids play a key role in the establishment of differential cells after asymmetric division, confinement of sE activity gene expression during the morphogenetic programme to the mother cell implies that SpoIIGA-mediated pro-sE of sporulation in B. subtilis. processing is delayed until after septation, with the possi- bility that it occurs only in the mother cell (Losick and Stragier, 1996). The proteolytic activation of sE requires Results the activity of sF through the activity of the sF-directed The effect of inhibition of the de novo fatty acid gene spoIIR (Karow et al., 1995; London˜o-Vallejo and synthesis on sporulation Stragier, 1995). It has been suggested by Losick and Stragier (1996) that spoIIR would be transcribed by sF in To determine the role of de novo fatty acid synthesis on the prespore and act as a vectorial cell–cell signal that sporulation, we used the antibiotic cerulenin. This antibiotic would activate sE only in the mother cell. Consistent with is a potent inhibitor of lipid synthesis known to irreversibly SpoIIR acting as a cell–cell signal, characterization of alkylate an essential thiol group of b-ketoacyl-ACP syn- the spoIIR gene indicated that it encoded a protein with thase, the enzyme that catalyses the condensation of a secretion signal, and recent biochemical analysis has malonyl-CoA with acyl-ACP (D’Agnolo et al., 1973). Thus, shown that SpoIIR is secreted (Hoffmeister et al., 1995). cerulenin inhibits the fatty acid chain elongation step and Once secreted, SpoIIR could interact with the membrane- thereby lipid synthesis (Fig. 1). Cerulenin (10 mgml¹1)was bound SpoIIGA that cleaves the pro sequence from sE added to strain JH642 grown in DS medium at different to activate it. Thus, the main function of SpoIIR would be times: 1.5 h (t¹1.5) and 0.5 h (t¹0.5) before cells enter sta- to tie the transcription programme in the mother cell to tionary phase, at the onset of stationary phase (t0)orat the transcription programme in the forespore by allowing several times after t0 (Fig. 2). Cerulenin was a potent inhi- E F s to become active only after s has itself been activated bitor of spore formation when added to cells at t¹1, t0 or E and thus ensuring that s does not become active in the t0.5; however, this inhibitory effect disappeared when the predivisional sporangium. Although this model is intriguing, antibiotic was added at more advanced stages of sporula- E the notion that SpoIIR must act vectorially to activate pro-s tion (t1 to t4) (Fig. 2). Typically, 16 h after reaching station- processing is not without controversy. Zhang et al. (1996) ary phase, cells treated with cerulenin at t0 had a viable observed that sE activation was limited to the mother cell count of about 108 ml¹1 and produced about 106 spores compartment, even when SpoIIR was synthesized before ml¹1. In contrast, in the absence of cerulenin, strain septation and therefore presumed to be present in both JH642 had a viable count of about 6 × 108 ml¹1 and pro- compartments. These authors conclude that a sE activa- duced about 5 × 108 spores ml¹1. Monitoring the levels of tion factor other than SpoIIR, possibly SpoIIGA in a parti- fatty acid synthesis in the experiments shown in Fig. 2 cular orientation, could be restricted to the mother cell. revealed that de novo incorporation of [14C]-acetate into The identity of the factor(s) responsible for cell compart- phospholipids of cerulenin-treated cells decreased about ment-specific activation of sE and the details of how the 90% when compared with non-treated cells (data not directional processing is accomplished remain to be shown).
Load more

Recommended publications
  • Short Chain Fatty Acid Biosynthesis in Microalgae Synechococcus Sp. PCC 7942
    marine drugs Article Short Chain Fatty Acid Biosynthesis in Microalgae Synechococcus sp. PCC 7942 Yi Gong 1,2,3 and Xiaoling Miao 1,2,3,* 1 State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; [email protected] 2 Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai 200240, China 3 Biomass Energy Research Center, Shanghai Jiao Tong University, Shanghai 200240, China * Correspondence: [email protected]; Tel.: +86-21-34207028 Received: 19 April 2019; Accepted: 25 April 2019; Published: 28 April 2019 Abstract: Short chain fatty acids (SCFAs) are valued as a functional material in cosmetics. Cyanobacteria can accumulate SCFAs under some conditions, the related mechanism is unclear. Two potential genes Synpcc7942_0537 (fabB/F) and Synpcc7942_1455 (fabH) in Synechococcus sp. PCC 7942 have homology with fabB/F and fabH encoding β-ketoacyl ACP synthases (I/II/III) in plants. Therefore, effects of culture time and cerulenin on SCFAs accumulation, expression levels and functions of these two potential genes were studied. The results showed Synechococcus sp. PCC 7942 accumulated high SCFAs (C12 + C14) in early growth stage (day 4) and at 7.5g/L cerulenin concentration, reaching to 2.44% and 2.84% of the total fatty acids respectively, where fabB/F expression was down-regulated. Fatty acid composition analysis showed C14 increased by 65.19% and 130% respectively, when fabB/F and fabH were antisense expressed. C14 increased by 10.79% (fab(B/F)−) and 6.47% (fabH−) under mutation conditions, while C8 increased by six times in fab(B/F)− mutant strain.
    [Show full text]
  • Inhibition of the Fungal Fatty Acid Synthase Type I Multienzyme Complex
    Inhibition of the fungal fatty acid synthase type I multienzyme complex Patrik Johansson*, Birgit Wiltschi*, Preeti Kumari†, Brigitte Kessler*, Clemens Vonrhein‡, Janet Vonck†, Dieter Oesterhelt*§, and Martin Grininger*§ *Department of Membrane Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany; †Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt, Germany; and ‡Global Phasing Ltd., Sheraton House, Castle Park, Cambridge CB3 0AX, United Kingdom Communicated by Hartmut Michel, Max Planck Institute for Biophysics, Frankfurt, Germany, June 23, 2008 (received for review March 6, 2008) Fatty acids are among the major building blocks of living cells, isoniazid and triclosan, both inhibiting the ER step of bacterial making lipid biosynthesis a potent target for compounds with fatty acid biosynthesis (6, 7). Several inhibitors targeting the antibiotic or antineoplastic properties. We present the crystal ketoacyl synthase (KS) step of the FAS cycle have also been structure of the 2.6-MDa Saccharomyces cerevisiae fatty acid syn- described, including cerulenin (CER) (8), thiolactomycin (TLM) thase (FAS) multienzyme in complex with the antibiotic cerulenin, (9), and the recently discovered platensimycin (PLM) (10). The representing, to our knowledge, the first structure of an inhibited polyketide CER inhibits both FAS type I and II KS enzymes, by fatty acid megasynthase. Cerulenin attacks the FAS ketoacyl syn- covalent modification of the active site cysteine and by occupying thase (KS) domain, forming a covalent bond to the active site the long acyl-binding pocket (11, 12). TLM and PLM, in contrast, cysteine C1305. The inhibitor binding causes two significant con- have been shown to be selective toward the FAS II system, formational changes of the enzyme.
    [Show full text]
  • Effect of Cerulenin on Fatty Acid Composition and Gene Expression
    Wan et al. Microb Cell Fact (2016) 15:30 DOI 10.1186/s12934-016-0431-9 Microbial Cell Factories RESEARCH Open Access Effect of cerulenin on fatty acid composition and gene expression pattern of DHA‑producing strain Colwellia psychrerythraea strain 34H Xia Wan1,2*, Yun‑Feng Peng1, Xue‑Rong Zhou3,4, Yang‑Min Gong1, Feng‑Hong Huang1,2 and Gabriel Moncalián5* Abstract Background: Colwellia psychrerythraea 34H is a psychrophilic bacterium able to produce docosahexaenoic acid (DHA). Polyketide synthase pathway is assumed to be responsible for DHA production in marine bacteria. Results: Five pfa genes from strain 34H were confirmed to be responsible for DHA formation by heterogene‑ ous expression in Escherichia coli. The complexity of fatty acid profile of this strain was revealed by GC and GC–MS. Treatment of cells with cerulenin resulted in significantly reduced level of C16 monounsaturated fatty acid (C16:1Δ9t, C16:1Δ7). In contrast, the amount of saturated fatty acids (C10:0, C12:0, C14:0), hydroxyl fatty acids (3-OH C10:0 and 3-OH C12:0), as well as C20:4ω3, C20:5ω3 and C22:6ω3 were increased. RNA sequencing (RNA-Seq) revealed the altered gene expression pattern when C. psychrerythraea cells were treated with cerulenin. Genes involved in polyke‑ tide synthase pathway and fatty acid biosynthesis pathway were not obviously affected by cerulenin treatment. In contrast, several genes involved in fatty acid degradation or β-oxidation pathway were dramatically reduced at the transcriptional level. Conclusions: Genes responsible for DHA formation in C. psychrerythraea was first cloned and characterized. We revealed the complexity of fatty acid profile in this DHA-producing strain.
    [Show full text]
  • Downloaded from Bioscientifica.Com at 09/28/2021 06:00:02AM Via Free Access + 346 S YAMADA and Others · Glucose Primes -Cells in a Ca2 -Independent Manner
    345 Time-dependent potentiation of the -cell is a Ca2+-independent phenomenon S Yamada, M Komatsu, T Aizawa, Y Sato, H Yajima, T Yada1, S Hashiguchi2, K Yamauchi and K Hashizume Department of Aging Medicine and Geriatrics, Shinshu University School of Medicine, Matsumoto 390–8621, Japan 1Department of Physiology, Jichi Medical School, Minamikawachi, Kawachi, Tochigi 329–0498, Japan 2Department of 2nd Internal Medicine, Faculty of Medicine, Kagoshima University, Kagoshima 890–8520, Japan (Requests for offprints should be addressed to M Komatsu; Email: [email protected]) Abstract When isolated rat pancreatic islets are treated with However, cerulenin or tunicamycin, two inhibitors of 16·7 mM glucose, a time-dependent potentiation (TDP) protein acylation, eradicated TDP without affecting glu- of insulin release occurs that can be detected by subse- cose metabolism. The TDP by glucose was not associated quent treatment with 50 mM KCl. It has been thought with an increase in the cytosolic free Ca2+ concentration that TDP by glucose is a Ca2+-dependent phenomenon ([Ca2+]i) during subsequent treatment with high K+. and only occurs when exposure to glucose is carried out in Exposure of islets to forskolin under Ca2+-free conditions the presence of Ca2+. In contrast to this, we now did not cause TDP despite a large increase in the cellular demonstrate TDP under stringent Ca2+-free conditions cAMP levels. In conclusion, glucose alone induces TDP (Ca2+-free buffer containing 1 mM EGTA). In fact, under under stringent Ca2+-free conditions when [Ca2+]i was these Ca2+-free conditions glucose caused an even significantly lowered.
    [Show full text]
  • Fatty Acid Synthase Inhibition Activates AMP-Activated Protein Kinase in SKOV3 Human Ovarian Cancer Cells
    Research Article Fatty Acid Synthase Inhibition Activates AMP-Activated Protein Kinase in SKOV3 Human Ovarian Cancer Cells Weibo Zhou,1 Wan Fang Han,1 Leslie E. Landree,2 Jagan N. Thupari,1 Michael L. Pinn,1 Tsion Bililign,6 Eun Kyoung Kim,2 Aravinda Vadlamudi,7 Susan M. Medghalchi,7 Rajaa El Meskini,7 Gabriele V. Ronnett,2,3 Craig A. Townsend,6 and Francis P. Kuhajda1,4,5 Departments of 1Pathology, 2Neuroscience, 3Neurology, 4Oncology, and 5Biological Chemistry, The Johns Hopkins University School of Medicine; 6Department of Chemistry, The Johns Hopkins University; and 7FASgen, Inc., Baltimore, Maryland Abstract cancers (2). Fatty acid synthase (FAS), the enzyme responsible for the de novo synthesis of fatty acids, has emerged as a potential Fatty acid synthase (FAS), the enzyme responsible for the therapeutic target for human cancer. FAS catalyzes the condensa- de novo synthesis of fatty acids, is highly expressed in ovarian tion of malonyl-CoA and acetyl-CoA to produce long-chain fatty cancers and most common human carcinomas. Inhibition of acids (3). High levels of FAS expression have been found in ovarian FAS and activation of AMP-activated protein kinase (AMPK) cancer (4, 5) and in most human solid tumors (6). The up-regulation have been shown to be cytotoxic to human cancer cells in vitro of FAS expression in cancer cells has been linked to both mitogen- and in vivo. In this report, we explore the cytotoxic mechanism activated protein kinase and phosphatidylinositol 3-kinase path- of action of FAS inhibition and show that C93, a synthetic FAS ways through the sterol regulatory binding element binding protein inhibitor, increases the AMP/ATP ratio, activating AMPK in 1c (7–9).
    [Show full text]
  • Genetic Manipulations of Fatty Acid Metabolism in -Cells Are Associated with Dysregulated Insulin Secretion
    Genetic Manipulations of Fatty Acid Metabolism in ␤-Cells Are Associated With Dysregulated Insulin Secretion Kazuhiro Eto,1 Tokuyuki Yamashita,1 Junji Matsui,1 Yasuo Terauchi,1 Mitsuhiko Noda,2 and Takashi Kadowaki1 Triacylglyceride (TG) accumulation in pancreatic ␤-cells is associated with impaired insulin secretion, which is called lipotoxicity. To gain a better under- t has been widely known that the accumulation of standing of the pathophysiology of lipotoxicity, we gen- triacylglycerides (TGs) in pancreatic ␤-cells is asso- erated three models of dysregulated fatty acid ciated with dysfunction of the cells, including im- metabolism in ␤-cells. The overexpression of sterol Ipaired insulin secretory response to glucose and regulatory element binding protein-1c induced lipogenic lipoapoptosis (1–3). The mechanisms by which TG accu- genes and TG accumulation. Under these conditions, we mulation leads to these dysfunctions, however, have re- observed a decrease in glucose oxidation and upregula- mained largely elusive. In the present study, we tion of uncoupling protein-2, which might be causally established three models of dysregulated metabolism of related to the decreased glucose-stimulated insulin se- fatty acids in ␤-cells and studied their effects on cell cretion. The overexpression of AMP-activated protein functions, especially insulin secretion, as follows: 1) over- kinase was accompanied by decreased lipogenesis, in- expression of sterol regulatory element binding protein creased fatty acid oxidation, and decreased glucose (SREBP)-1c (a master transcription factor for lipogenesis oxidation; insulin secretions to glucose and depolariza- [4–7]) in ␤-cells to reconstitute lipotoxicity with a geneti- tion stimuli were decreased, probably because of the cally determined cause; 2) overexpression of AMP-acti- decrease in glucose oxidation and cellular insulin con- vated protein kinase (AMPK; a metabolic master switch tent.
    [Show full text]
  • Validation and Application of a Novel Target-Based Whole-Cell Screen to Identify Antifungal Compounds
    University of Tennessee Health Science Center UTHSC Digital Commons Theses and Dissertations (ETD) College of Graduate Health Sciences 10-2020 Validation and Application of a Novel Target-Based Whole-Cell Screen to Identify Antifungal Compounds Christian Alexander DeJarnette Follow this and additional works at: https://dc.uthsc.edu/dissertations Part of the Analytical, Diagnostic and Therapeutic Techniques and Equipment Commons, Bacterial Infections and Mycoses Commons, Chemicals and Drugs Commons, Medical Biochemistry Commons, Medical Genetics Commons, and the Pharmaceutics and Drug Design Commons Validation and Application of a Novel Target-Based Whole-Cell Screen to Identify Antifungal Compounds Abstract Traditional approaches to drug discovery are inefficient and vha e several key limitations that constrain our capacity to rapidly identify and develop novel experimental therapeutics. To address this, we have devised a second-generation target-based whole-cell screening assay based on the principles of competitive fitness, which can apidlyr identify target-specific and physiologically-active compounds. Briefly, strains expressing high, intermediate, and low levels of a preselected target protein were constructed, tagged with spectrally distinct fluorescent proteins (FPs), and mixed together. The pooled strains were then grown in the presence of various small molecules, and the relative growth of each strain within the mixed culture was compared by measuring the intensity of the corresponding FP tags. Chemically-induced population shifts indicated that the bioactivity of a small molecule was dependent upon the target protein’s abundance and thus established a functional interaction. Here, we described the molecular tools required to apply this technique in the prevalent human fungal pathogen Candida albicans and validated this approach using dihydrofolate reductase.
    [Show full text]
  • Macrotyloma Uniflorum) Cultivated in High Altitudes of Uttarakhand Himalaya, India
    Sharma et al. Ind. J. Pure App. Biosci. (2019) 7(4), 190-202 ISSN: 2582 – 2845 Available online at www.ijpab.com DOI: http://dx.doi.org/10.18782/2320-7051.7614 ISSN: 2582 – 2845 Ind. J. Pure App. Biosci. (2019) 7(4), 190-202 Research Article Nutraceutical Evaluation of Horse Gram (Macrotyloma uniflorum) Cultivated in High Altitudes of Uttarakhand Himalaya, India Netrapal Sharma1*, Satpal Singh Bisht1, Sanjay Gupta2, Mahendra Rana3 and Ajay Kumar1 1*Department of Zoology, 3Department of Pharmaceutical Sciences, Kumaun University, Nainital – 263002, Uttarakhand, India 2Himalayan School of Biosciences, Swami Ram Nagar, Beside Jolly Grant Airport, Jolly Grant, Doiwala, Dehradun, Uttarakhand, 248016, India *Corresponding Author E-mail: [email protected] Received: 3.07.2019 | Revised: 8.08.2019 | Accepted: 17.08.2019 ABSTRACT Complete exploration of nutraceutical properties of Macrotyloma uniflorum by liquid chromatography mass spectrometry (LC-MS) and proximate analysis was performed. Seeds of M. uniflorum were collected from local farmers from the higher altitude (2178m, N-29°27.034’; E-079°46.210’). Three types of extracts were prepared with the help of soxhlet extractor and dried in vacuum dryer. The above extracts were examined by LC-MS (TOF/Q-TOF Mass Spectrometer) for the presence of alkaloids, glycosides, saponins, phenolic compounds, tannins followed by Macronutrients, micronutrients and proximate analysis followed by LC-MS analysis in Hydrolic (66), Ethanolic (66) and Methanolic extract (119). The maximum number of compounds was found in methanolic extract, compounds common in all solvents were (32), common in methanolic and ethanolic were (17) and common in methanolic and hydrolic were (11) respectively.
    [Show full text]
  • Fatty Acid Synthase: a Novel Target for Antiglioma Therapy
    British Journal of Cancer (2006) 95, 869 – 878 & 2006 Cancer Research UK All rights reserved 0007 – 0920/06 $30.00 www.bjcancer.com Fatty acid synthase: a novel target for antiglioma therapy *,1 2 2 1 2 1 1 W Zhao , S Kridel , A Thorburn , M Kooshki , J Little , S Hebbar and M Robbins 1Departments of Radiation Oncology and Neurosurgery, Brain Tumor Center of Excellence, Wake Forest University School of Medicine, Medical Center 2 Boulevard, Winston-Salem, NC 27157, USA; Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA High levels of fatty acid synthase (FAS) expression have been observed in several cancers, including breast, prostate, colon and lung carcinoma, compared with their respective normal tissue. We present data that show high levels of FAS protein in human and rat glioma cell lines and human glioma tissue samples, as compared to normal rat astrocytes and normal human brain. Incubating glioma cells with the FAS inhibitor cerulenin decreased endogenous fatty acid synthesis by approximately 50%. Cell cycle analysis demonstrated a time- and dose-dependent increase in S-phase cell arrest following cerulenin treatment for 24 h. Further, treatment with cerulenin resulted in time- and dose-dependent decreases in glioma cell viability, as well as reduced clonogenic survival. Increased apoptotic cell death and PARP cleavage were observed in U251 and SNB-19 cells treated with cerulenin, which was independent of the death receptor pathway. Overexpressing Bcl-2 inhibited cerulenin-mediated cell death. In contrast, primary rat astrocytes appeared unaffected. Finally, RNAi-mediated knockdown of FAS leading to reduced FAS enzymatic activity was associated with decreased glioma cell viability.
    [Show full text]
  • The Role of Lipid Droplets in Autophagy
    The Role of Lipid Droplets in Autophagy Author: Benjan Karnebeek S3157318 Supervisor: Prof. Dr. Ida J. van der Klei Molecular Cell Biology Date: 21-6-2019 1 Abstract: Autophagy is a process in which proteins and organelles are engulfed in vesicles and then degraded by lysosomes or vacuoles. Autophagy is a process important in cellular homeostasis and its malfunction has been tied to several diseases. Lipid Droplets (LDs) are organelles that function as storage of neutral lipids and play a central role in cellular lipid metabolism. This review will outline the connections between LDs and (macro)autophagy and the involvement of LDs in autophagy. First an overview will be given of all proteins (discovered so far to be) involved in both lipid metabolism and (macro)autophagy and their functions in both. The consequences will then be discussed. Finally more direct functions of LDs in autophagy will be shown and the implications of these functions discussed. Table of contents Introduction: ............................................................................................................................................ 3 Processes of autophagy and lipid droplet biogenesis: ............................................................................ 3 Proteins with dual functions: .................................................................................................................. 6 Direct functions of lipid droplets in autophagy: .................................................................................... 10 Closing
    [Show full text]
  • Malonyl-Coa Decarboxylase Inhibition Is Selectively Cytotoxic to Human Breast Cancer Cells
    Oncogene (2009) 28, 2979–2987 & 2009 Macmillan Publishers Limited All rights reserved 0950-9232/09 $32.00 www.nature.com/onc ORIGINAL ARTICLE Malonyl-CoA decarboxylase inhibition is selectively cytotoxic to human breast cancer cells W Zhou1,YTu2, PJ Simpson2 and FP Kuhajda1,3,4 1Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; 3Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA and 4Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA Fatty acid synthase (FAS) inhibition initiates selective glycolysis described in the 1920s by Otto Warburg apoptosis of cancer cells both in vivo and in vitro, which (Warburg et al., 1924). Despite access to adequate may involve malonyl-CoA metabolism. These findings oxygen, cancer cells continue to rely on glycolysis over have led to the exploration of malonyl-CoA decarboxylase respiration to generate adenosine triphosphate (ATP) (MCD) as a potential novel target for cancer treatment. (Elstrom et al., 2004). Recently, the convergence of MCD regulates the levels of cellular malonyl-CoA molecular biology and biochemistry has refocused through the decarboxylation of malonyl-CoA to acetyl- interest on cancer metabolism as an area of new targets CoA. Malonyl-CoA is both a substrate for FAS and an for cancer treatment. Our studies of cancer cell inhibitor of fatty acid oxidation acting as a metabolic metabolism led to the observation that transformed switch between anabolic fatty acid synthesis and catabolic cells exhibit high levels of fatty acid synthase (FAS) fatty acid oxidation.
    [Show full text]
  • Type I Fatty Acid Synthase (FAS) Trapped in the Octanoyl
    bioRxiv preprint doi: https://doi.org/10.1101/747683; this version posted August 28, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. Type I fatty acid synthase (FAS) trapped in the octanoyl- bound state Authors: Alexander Rittner, Karthik S. Paithankar, Aaron Himmler, and Martin Grininger* Author affiliations: Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, Frankfurt am Main, D-60438, Germany *Corresponding author: [email protected] Telephone number: +49 69 798 42705 1 bioRxiv preprint doi: https://doi.org/10.1101/747683; this version posted August 28, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. 1 Abstract 2 De novo fatty acid biosynthesis in humans is accomplished by a multidomain 3 protein, the type I fatty acid synthase (FAS). Although ubiquitously expressed 4 in all tissues, fatty acid synthesis is not essential in normal healthy cells due to 5 sufficient supply with fatty acids by the diet. However, FAS is overexpressed 6 in cancer cells and correlates with tumor malignancy, which makes FAS an 7 attractive selective therapeutic target in tumorigenesis. Herein, we present a 8 crystal structure of the condensing part of murine FAS, highly homologous to 9 human FAS, with octanoyl moieties covalently bound to the transferase (MAT) 10 and the condensation (KS) domain.
    [Show full text]