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Mitochondrial lipid synthesis in the model eukaryote, Trypanosoma brucei: identification of lipid biosynthesis complexes and contributions of individual pathways to mitochondrial structure and function

English title Mitochondrial lipid synthesis in the model eukaryote, Trypanosoma brucei: identification of lipid biosynthesis complexes and contributions of individual pathways to mitochondrial structure and function
Applicant Bütikofer Peter
Number 149353
Funding scheme Project funding (Div. I-III)
Research institution Institut für Biochemie und Molekulare Medizin Universität Bern
Institution of higher education University of Berne - BE
Main discipline Biochemistry
Start/End 01.11.2013 - 31.10.2016
Approved amount 520'000.00
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All Disciplines (2)

Discipline
Biochemistry
Molecular Biology

Keywords (7)

Mitochondrion; Respiratory chain complexes; Cardiolipin; Phospholipid synthesis; Trypanosoma brucei; Phosphatidylserine; Phosphatidylethanolamine

Lay Summary (German)

Lead
Lipidsynthese in Mitochondrien eines tödlichen Parasiten.
Lay summary

Der einzellige Parasit, Trypanosoma brucei, ist ein gefährlicher Krankheitserreger für Mensch und Nutztier. Er ist der Auslöser der Afrikanischen Schlafkrankheit, der jedes Jahr Tausende von Menschen in Afrika zum Opfer fallen. Erfolgt keine rechtzeitige Behandlung der Patienten mit Medikamenten, verläuft die Krankheit tödlich. Leider sind die zur Zeit verfügbaren Medikamente veraltet und haben zum Teil schwere Nebenwirkungen, die sogar zum Tod führen können. Damit neue Therapieansätze und Medikamente entwickelt werden können, braucht es die universitäre Grundlagenforschung.

Seit einigen Jahren studieren wir die Frage, wie in T. brucei die Herstellung von Membranlipiden – zellulären Bausteinen, die in jeder Zelle vorkommen – abläuft. Dabei konzentrieren wir uns auf Lipide, die in den Kraftwerken der Zelle, den Mitochondrien, vorkommen. Wir haben herausgefunden, dass gewisse chemische Reaktionen bei der Produktion dieser Lipide essentiell sind für das Wachstum von T. brucei; hemmt man diese Schritte, so verlangsamen die Parasiten ihr Wachstum und sterben schliesslich ab. Die fraglichen Lipide sind bei der Faltung und Funktion von Eiweissen, die bei der Energieproduktion in den Mitochondrien eine entscheidende Rolle spielen, beteiligt. Im aktuellen Forschungsprojekt untersuchen wir das Zusammenspiel zwischen diesen Lipiden und Proteinen in T. brucei. Die Resultate unserer Forschung werden nicht nur zum besseren Verständnis ähnlicher Vorgänge bei höheren Organismen beitragen, sondern auch Ansätze für die Bekämpfung von parasitären Krankheiten bei Mensch und Tier aufzeigen.

Die Universität Bern hat im Jahresbericht 2012 die Forschung an Trypanosomen als ‚Blickpunkt Forschung’ bezeichnet (http://www.unibe.ch/organisation/jahresbericht.html).

 

Direct link to Lay Summary Last update: 01.10.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Phosphatidylserine synthase 2 and phosphatidylserine decarboxylase are essential for aminophospholipid synthesis in Trypanosoma brucei Phosphatidylserine metabolism of T. brucei
Farine Luce, Jelk Jennifer, Choi Jae-Yeon, Voelker Dennis R., Nunes Jon, Smith Terry K., Bütikofer Peter (2017), Phosphatidylserine synthase 2 and phosphatidylserine decarboxylase are essential for aminophospholipid synthesis in Trypanosoma brucei Phosphatidylserine metabolism of T. brucei, in Molecular Microbiology, 104(3), 412-427.
RFT1 Protein Affects Glycosylphosphatidylinositol (GPI) Anchor Glycosylation
Gottier Petra, Gonzalez-Salgado Amaia, Menon Anant K., Liu Yuk-Chien, Acosta-Serrano Alvaro, Bütikofer Peter (2017), RFT1 Protein Affects Glycosylphosphatidylinositol (GPI) Anchor Glycosylation, in Journal of Biological Chemistry, 292(3), 1103-1111.
Evolution of the Protein Synthesis Machinery and Its Regulation
Eltschinger Sandra, Bütikofer Peter, Altmann Michael (2016), Evolution of the Protein Synthesis Machinery and Its Regulation, in Greco Hernández (ed.), 277-311.
Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)
Klionsky Daniel J., Abdelmohsen Kotb, Abe Akihisa, Abedin Md Joynal, Abeliovich Hagai, Arozena Abraham Acevedo, Adachi Hiroaki, Adams Christopher M., Adams Peter D., Adeli Khosrow, Adhihetty Peter J., Adler Sharon G., Agam Galila, Agarwal Rajesh, Aghi Manish K., Agnello Maria, Agostinis Patrizia, Aguilar Patricia V., Aguirre-Ghiso Julio, Airoldi Edoardo M., Ait-Si-Ali Slimane, Akematsu Takahiko, Akporiaye Emmanuel T., Al-Rubeai Mohamed, Albaiceta Guillermo M. (2016), Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition), in AUTOPHAGY, 12(1), 1-222.
Lipid topogenesis — 35 years on
Chauhan Neha, Farine Luce, Pandey Kalpana, Menon Anant K., Bütikofer Peter (2016), Lipid topogenesis — 35 years on, in Biochim Biophys Acta, 1861, 757-766.
A Glycosylation Mutant of Trypanosoma brucei Links Social Motility Defects In Vitro to Impaired Colonization of Tsetse Flies In Vivo.
Imhof Simon, Vu Xuan Lan, Bütikofer Peter, Roditi Isabel (2015), A Glycosylation Mutant of Trypanosoma brucei Links Social Motility Defects In Vitro to Impaired Colonization of Tsetse Flies In Vivo., in Eukaryotic Cell, 14(6), 588-92.
An Atypical Mitochondrial Carrier That Mediates Drug Action in Trypanosoma brucei
de Macedo Juan P., Burkard Gabriela Schumann, Niemann Moritz, Barrett Michael P., Vial Henri, Maeser Pascal, Roditi Isabel, Schneider Andre, Buetikofer Peter (2015), An Atypical Mitochondrial Carrier That Mediates Drug Action in Trypanosoma brucei, in PLOS PATHOGENS, 11(5), e1004875.
Flagellar membranes are rich in raft-forming phospholipids
Serricchio Mauro, Schmid Adrien W., Steinmann Michael E., Sigel Erwin, Rauch Monika, Julkowska Daria, Bonnefoy Serge, Fort Cecile, Bastin Philippe, Buetikofer Peter (2015), Flagellar membranes are rich in raft-forming phospholipids, in BIOLOGY OPEN, 4(9), 1143-1153.
Phosphatidylethanolamine and phosphatidylcholine biosynthesis by the Kennedy pathway occurs at different sites in Trypanosoma brucei
Farine Luce, Niemann Moritz, Schneider Andre, Buetikofer Peter (2015), Phosphatidylethanolamine and phosphatidylcholine biosynthesis by the Kennedy pathway occurs at different sites in Trypanosoma brucei, in SCIENTIFIC REPORTS, 5, 16787.
TrypanoCyc: a community-led biochemical pathways database for Trypanosoma brucei
Shameer Sanu, Logan-Klumpler Flora J., Vinson Florence, Cottret Ludovic, Merlet Benjamin, Achcar Fiona, Boshart Michael, Berriman Matthew, Breitling Rainer, Bringaud Fredrric, Butikofer Peter, Cattanach Amy M., Bannerman-Chukualim Bridget, Creek Darren J., Crouch Kathryn, de Koning Harry P., Denise Hubert, Ebikeme Charles, Fairlamb Alan H., Ferguson Michael A. J., Ginger Michael L., Hertz-Fowler Christiane, Kerkhoven Eduard J., Maeser Pascal, Michels Paul A. M. (2015), TrypanoCyc: a community-led biochemical pathways database for Trypanosoma brucei, in NUCLEIC ACIDS RESEARCH, 43(D1), 637-644.
Trypanosoma brucei Bloodstream Forms Depend upon Uptake of myo-Inositol for Golgi Complex Phosphatidylinositol Synthesis and Normal Cell Growth
Gonzalez-Salgado Amaia, Steinmann Michael, Major Louise L., Sigel Erwin, Reymond Jean-Louis, Smith Terry K., Buetikofer Peter (2015), Trypanosoma brucei Bloodstream Forms Depend upon Uptake of myo-Inositol for Golgi Complex Phosphatidylinositol Synthesis and Normal Cell Growth, in EUKARYOTIC CELL, 14(6), 616-624.
Autophagy in Trypanosoma brucei: Amino Acid Requirement and Regulation during Different Growth Phases
Schmidt Remo S., Buetikofer Peter (2014), Autophagy in Trypanosoma brucei: Amino Acid Requirement and Regulation during Different Growth Phases, in PLOS ONE, 9(4), e93875.

Collaboration

Group / person Country
Types of collaboration
Prof. Dennis Voelker, National Jewish Health, Denver United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Dr. Adrien Schmid, EPFL, Lausanne Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. André Schneider, Departement für Chemie & Biochemie, Universität Bern, Bern Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Biozentrum, Universität Würzburg Individual talk Trypanosoma brucei cardiolipin: one head, two backbones, four legs and many functions 28.04.2016 Würzburg, Germany Bütikofer Peter;
33rd Annual Swiss Trypanosomatid Meeting Poster Cardiolipin synthesis in T. brucei: a protein interaction study 20.01.2016 Leysin, Switzerland Bütikofer Peter; Weber Petra;
33rd Annual Swiss Trypanosomatid Meeting Talk given at a conference Role of phosphatidic acid phosphatase in lipid metabolism in T. brucei 20.01.2016 Leysin, Switzerland Dawoody Nejad Ladan;
33rd Annual Swiss Trypanosomatid Meeting Talk given at a conference Discovery of novel cardiolipin-dependent proteins in T. brucei 20.01.2016 Leysin, Switzerland Schädeli David;
Cardiolipin as Key Lipid of Mitochondria in Health and Disease Talk given at a conference Cardiolipin synthase in Trypanosoma brucei: a model system to study cardiolipin-dependent protein expression and identify interaction partners 01.10.2015 Florenz, Italy Schädeli David; Bütikofer Peter;
Cardiolipin as Key Lipid of Mitochondria in Health and Disease Poster Impact of cardiolipin depletion on mitochondrial respiratory chain complexes in Trypanosoma brucei 01.10.2015 Florenz, Italy Bütikofer Peter; Schädeli David;
ASBMB Annual Meeting Poster The Perinuclear Endoplasmic Reticulum as the Site of Phosphatidylethanolamine Synthesis in a Model Eukaryote 29.03.2015 Boston, United States of America Bütikofer Peter;
32nd Annual Swiss Trypanosomatid Meeting Talk given at a conference The mitochondrion ER interface in trypanosomes - myth or truth? 21.01.2015 Leysin, Switzerland Bütikofer Peter;
32nd Annual Swiss Trypanosomatid Meeting Poster Impact of cardiolipin depletion on protein levels and protein complexes in T. brucei 21.01.2015 Leysin, Switzerland Bütikofer Peter; Schädeli David;
32nd Annual Swiss Trypanosomatid Meeting Poster Role of phosphatidic acid phosphatase in lipid metabolism in T. brucei 21.01.2015 Leysin, Switzerland Bütikofer Peter; Dawoody Nejad Ladan;
Virologisch – parasitologisches Seminar, Philipps-Universität Marburg Individual talk Trypanosoma brucei Cardiolipin Synthase: An Essential Bacterial-type Enzyme in a Eukaryote 30.01.2014 Marburg, Germany Bütikofer Peter;
31st Annual Swiss Trypanosomatid Meeting Poster Effects of cardiolipin depletion on mitochondrial respiratory complex activities 22.01.2014 Leysin, Switzerland Bütikofer Peter; Schädeli David;
31st Annual Swiss Trypanosomatid Meeting Talk given at a conference Functional complementation of cardiolipin synthase-deficient yeast and E. coli with T. brucei cardiolipin synthase 22.01.2014 Leysin, Switzerland Weber Petra;
31st Annual Swiss Trypanosomatid Meeting Talk given at a conference Localization and characterization of key enzymes involved in PE biosynthesis in T. brucei 22.01.2014 Leysin, Switzerland Bütikofer Peter;


Associated projects

Number Title Start Funding scheme
141913 Transporters of Trypanosoma brucei: Phylogeny - Physiology - Pharmacology 01.06.2013 Sinergia
130815 Novel biosynthetic pathways in Trypanosoma brucei: Biosynthesis of phospholipids and modification of eEF1A 01.08.2010 Project funding (Div. I-III)
169355 Mitochondrial lipid synthesis in Trypanosoma brucei: protein complexes forming lipids and lipids forming protein complexes 01.11.2016 Project funding (Div. I-III)

Abstract

The World Health Organisation has classified human African sleeping sickness as neglected tropical disease and has implemented several programs to control its spread and transmission. The disease is caused by the protozoan parasite, Trypanosoma brucei, which is transmitted between mammalian hosts by the tsetse insect vector. Because of a threat of emerging resistance against key drugs against African trypanosomes, and because currently available drugs show potentially life-threatening toxicity and efficacy problems, major efforts to identify novel trypanosome candidate target molecules or pathways for drug development are needed.T. brucei has also emerged as valuable model organism to study general biological processes, such as antigenic variation, glycosylphosphatidylinositol-anchoring, membrane and organelle formation, and cell differentiation. Trypanosomes can easily be propagated in vitro and are amenable to reverse genetic approaches, including inducible RNAi-mediated silencing of gene expression and gene knock-out by homologous recombination. During the last decade, we have worked on the elucidation of pathways involved in lipid modifications of proteins and de novo synthesis of phospholipids in T. brucei. We have experimentally established the enzymatic reaction sequences leading to the production of phosphatidylethanolamine (PE), a major membrane phospholipid in T. brucei, and more recently, of phosphatidylglycerol (PG) and cardiolipin (CL), two signature lipids of mitochondria. Our results have demonstrated that de novo formation of PE, PG and CL is essential for growth of T. brucei procyclic (insect) and bloodstream form parasites in culture, validating the enzymes and metabolites involved in these pathways as potential drug targets.It is well known that PE, PG and CL are required for proper function of several mitochondrial membrane proteins, in particular those belonging to the respiratory chain. In addition, they are involved in the formation and/or stability of high molecular mass protein complexes of the inner mitochondrial membrane. The availability in our laboratory of inducible knock-out and knock-down trypanosomes deficient in de novo PE, PG and CL synthesis will allow us to study the roles of these phospholipids in protein function and stability in a controlled, i.e. inducible and time-dependent, and thus more detailed way than in other eukaryotic model organisms. We plan to characterize the substrate specificity of T. brucei cardiolipin synthase, the first ever exerimentally identified prokaryotic-type CL synthase in a eukaryote, and study if the trypanosome enzyme is able to complement CL synthase-deficient yeast or bacterial strains. In addition, we aim to partially purify and characterize the protein complexes associated with CL synthase and phosphatidylglycerophosphate synthase and investigate the effects of CL and PG depletion on T. brucei mitochondrial membrane complex formation.Another focus of the grant application addresses the localization of key enzymes involved in de novo PE synthesis and proposes to determine the contributions of different routes, such as the CDP-ethanolamine pathway, phosphatidylserine decarboxylation and degradation of sphingolipids, to PE formation in T. brucei.
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