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Novel biosynthetic pathways in Trypanosoma brucei: Biosynthesis of phospholipids and modification of eEF1A

Applicant Bütikofer Peter
Number 130815
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 01.08.2010 - 31.10.2013
Approved amount 375'000.00
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All Disciplines (2)

Discipline
Biochemistry
Molecular Biology

Keywords (15)

Trypanosoma brucei; Phospholipid synthesis; Cardiolipin; Phosphatidylethanolamine; Phosphatidylserine; Eukaryotic elongation factor 1A; Protein modification; Trypanosomes; membranes; phospholipids; biosynthesis; mitochondrium; eEF1A; Lipids; Metabolism

Lay Summary (English)

Lead
Lay summary
African trypanosomes are protozoan parasites causing human African sleeping sickness and a related disease, Nagana, in cattle. These diseases have a major impact on human and animal health by severely affecting social and economic development among the poorest, mostly rural, populations in sub-Saharan Africa. During their complex life cycles, Trypanosoma brucei parasites alternate between the mammalian bloodstream and the insect host, the tsetse fly. Interestingly, research on trypanosomes has led to the discovery of several important biological phenomena, such as RNA editing, trans-splicing, GPI-anchoring and antigenic variation, which were subsequently found to occur in other eukaryotic organisms as well.A major focus of our research is to study the biosynthesis and metabolism of phospholipids, the major building blocks of most biological membranes, in T. brucei parasites. This area of research that has received little attention in the past, but is currently investigated as potential drug target to fight sleeping sickness, and other neglected tropical diseases. We have recently shown that the structure of the major energy-producing organelle, the mitochondrion, in T. brucei is severely affected by changes in the cellular phospholipid composition. We now focus on establishing in T. brucei parasites the biosynthetic pathways required for the production of several phospholipid classes that have been shown to be important for the functional integrity of mitochondria in eukaryotes.Another research focus of our laboratory, using T. brucei as a eukaryotic model organism, is on a rare protein modification, i.e. ethanolamine phosphoglycerol (EPG) bound to eukaryotic elongation factor 1A (eEF1A). Such modifications often regulate the biological function of a protein, its distribution within a cell, and interactions with partner molecules. We are currently studying the protein sequence requirement for EPG attachment to eEF1A, its pathway of synthesis, and functional significance. The results from these studies will delineate a novel pathway for protein modification and, hopefully, shed light on its importance for eEF1A function.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Characterization of choline uptake in Trypanosoma brucei procyclic and bloodstream forms.
Macêdo Juan P, Schmidt Remo S, Mäser Pascal, Rentsch Doris, Vial Henri J, Sigel Erwin, Bütikofer Peter (2013), Characterization of choline uptake in Trypanosoma brucei procyclic and bloodstream forms., in Molecular and biochemical parasitology, 190(1), 16-22.
Glycoprotein biosynthesis in a eukaryote lacking the membrane protein Rft1.
Jelk Jennifer, Gao Ningguo, Serricchio Mauro, Signorell Aita, Schmidt Remo S, Bangs James D, Acosta-Serrano Alvaro, Lehrman Mark A, Bütikofer Peter, Menon Anant K (2013), Glycoprotein biosynthesis in a eukaryote lacking the membrane protein Rft1., in The Journal of biological chemistry, 288(28), 20616-23.
Increased placental phospholipid levels in pre-eclamptic pregnancies.
Huang Xiao, Jain Arjun, Baumann Marc, Körner Meike, Surbek Daniel, Bütikofer Peter, Albrecht Christiane (2013), Increased placental phospholipid levels in pre-eclamptic pregnancies., in International journal of molecular sciences, 14(2), 3487-99.
Lipid synthesis in protozoan parasites: A comparison between kinetoplastids and apicomplexans.
Ramakrishnan Srinivasan, Serricchio Mauro, Striepen Boris, Bütikofer Peter (2013), Lipid synthesis in protozoan parasites: A comparison between kinetoplastids and apicomplexans., in Progress in lipid research, 52(4), 488-512.
Phosphatidylglycerophosphate synthase associates with a mitochondrial inner membrane complex and is essential for growth of Trypanosoma brucei.
Serricchio Mauro, Bütikofer Peter (2013), Phosphatidylglycerophosphate synthase associates with a mitochondrial inner membrane complex and is essential for growth of Trypanosoma brucei., in Molecular microbiology, 87(3), 569-79.
The ins and outs of phosphatidylethanolamine synthesis in Trypanosoma brucei.
Farine Luce, Bütikofer Peter (2013), The ins and outs of phosphatidylethanolamine synthesis in Trypanosoma brucei., in Biochimica et biophysica acta, 1831(3), 533-42.
Unique posttranslational modifications in eukaryotic translation factors and their roles in protozoan parasite viability and pathogenesis.
Mittal Nimisha, Subramanian Gowri, Bütikofer Peter, Madhubala Rentala (2013), Unique posttranslational modifications in eukaryotic translation factors and their roles in protozoan parasite viability and pathogenesis., in Molecular and biochemical parasitology, 187(1), 21-31.
An essential bacterial-type cardiolipin synthase mediates cardiolipin formation in a eukaryote.
Serricchio Mauro, Bütikofer Peter (2012), An essential bacterial-type cardiolipin synthase mediates cardiolipin formation in a eukaryote., in Proceedings of the National Academy of Sciences of the United States of America, 109(16), E954-E961.
Ethanolamine phosphoglycerol attachment to eEF1A is not essential for normal growth of Trypanosoma brucei.
Greganova Eva, Bütikofer Peter (2012), Ethanolamine phosphoglycerol attachment to eEF1A is not essential for normal growth of Trypanosoma brucei., in Scientific reports, 2, 254-254.
Eukaryotic translation elongation factor 1A (eEF1A) domain I from S. cerevisiae is required but not sufficient for inter-species complementation.
Eltschinger Sandra, Greganova Eva, Heller Manfred, Bütikofer Peter, Altmann Michael (2012), Eukaryotic translation elongation factor 1A (eEF1A) domain I from S. cerevisiae is required but not sufficient for inter-species complementation., in PloS one, 7(7), 42338-42338.
myo-Inositol uptake is essential for bulk inositol phospholipid but not glycosylphosphatidylinositol synthesis in Trypanosoma brucei.
Gonzalez-Salgado Amaia, Steinmann Michael E, Greganova Eva, Rauch Monika, Mäser Pascal, Sigel Erwin, Bütikofer Peter (2012), myo-Inositol uptake is essential for bulk inositol phospholipid but not glycosylphosphatidylinositol synthesis in Trypanosoma brucei., in The Journal of Biological Chemistry, 287(16), 13313-23.
Trypanosoma brucei: a model micro-organism to study eukaryotic phospholipid biosynthesis
Serricchio Mauro, Bütikofer Peter (2011), Trypanosoma brucei: a model micro-organism to study eukaryotic phospholipid biosynthesis, in FEBS J., 278, 1035-1046.
Unique modifications of translation elongation factors.
Greganova Eva, Altmann Michael, Bütikofer Peter (2011), Unique modifications of translation elongation factors., in The FEBS Journal, 278(15), 2613-24.
A structural domain mediates attachment of ethanolamine phosphoglycerol to eukaryotic elongation factor 1A in Trypanosoma brucei.
Greganova Eva, Heller Manfred, Bütikofer Peter (2010), A structural domain mediates attachment of ethanolamine phosphoglycerol to eukaryotic elongation factor 1A in Trypanosoma brucei., in PloS one, 5(3), 9486-9486.
Lipid metabolism in Trypanosoma brucei.
Smith Terry K, Bütikofer Peter (2010), Lipid metabolism in Trypanosoma brucei., in Molecular and biochemical parasitology, 172(2), 66-79.
Lipid remodelling of glycosylphosphatidylinositol (GPI) glycoconjugates in procyclic-form trypanosomes: biosynthesis and processing of GPIs revisited.
Bütikofer Peter, Greganova Eva, Liu Yuk-Chien, Edwards Ian J, Lehane Michael J, Acosta-Serrano Alvaro (2010), Lipid remodelling of glycosylphosphatidylinositol (GPI) glycoconjugates in procyclic-form trypanosomes: biosynthesis and processing of GPIs revisited., in The Biochemical journal, 428(3), 409-18.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
11th Euro Fed Lipid Congress Talk given at a conference Contributions of different biosynthetic pathways to PE formation in T. brucei 27.10.2013 Antalya, Turkey Farine Luce;
Cardiolipin as Key Lipid of Mitochondria in Health and Disease Talk given at a conference The essential role of a bacterial-type cardiolipin synthase in a eukaryote 17.09.2013 Bari, Italy Bütikofer Peter;
53rd International Conference on the Biosciences of Lipids (ICBL) Poster The essential bacterial-type cardiolipin synthase of Trypanosoma brucei localizes to a mitochondrial complex 04.09.2013 Banff, Canada Serricchio Mauro; Bütikofer Peter;
5th Kinetoplast Molecular Cell Biology Conference Poster Phosphatidylethanolamine synthesis in Trypanosoma brucei 21.04.2013 Woods Hole, United States of America Bütikofer Peter; Farine Luce;
30th Swiss Trypanosomatid Meeting Talk given at a conference Contribution of alternative substrate sources and pathways to de novo synthesis of PE in T. brucei 23.01.2013 Leysin, Switzerland Farine Luce;
30th Swiss Trypanosomatid Meeting Poster Elucidating the Composition of the Cardiolipin Synthase Complex in T. brucei 23.01.2013 Leysin, Switzerland Weber Petra; Serricchio Mauro;
Southeast Regional Lipid Conference Talk given at a conference Trypnaosoma brucei: a model organism to study eukaryotic phospholipid synthesis 09.11.2012 Cashiers, NC, United States of America Bütikofer Peter;
29th Swiss Trypanosomatid Meeting Talk given at a conference The phospholipid cardiolipin is required for mitochondrial protein complex stability in T. brucei 25.01.2012 Leysin, Switzerland, Switzerland Serricchio Mauro;
Indo-Swiss Symposium on Parasitic Diseases / Infectious Diseases Talk given at a conference The Ins and Outs of Phospholipid Biosynthesis in Trypanosoma brucei 03.11.2011 New Delhi, India, India Bütikofer Peter;
4th Kinetoplast Molecular Cell Biology Conference Poster Identification of an essential myo-inositol transporter in T. brucei 08.04.2011 Woods Hole, MA, USA, United States of America Bütikofer Peter;
28th Swiss Trypanosomatid Meeting Talk given at a conference Biosynthesis of the mitochondrial phospholipid, cardiolipin, is essential in T. brucei 26.01.2011 Leysin, Switzerland, Switzerland Serricchio Mauro;
51st International Conference on the Biosciences of Lipids (ICBL) Poster Cardiolipin synthesis by a bacterial-type enzyme in a eukaryote 07.09.2010 Bilbao, Spain, Spain Bütikofer Peter; Serricchio Mauro;


Self-organised

Title Date Place
Microbial Lipids: Diversity in Structure and Function (FEBS Workshop) 16.05.2012 Bern, Switzerland, Switzerland

Communication with the public

Communication Title Media Place Year
Media relations: print media, online media Hoffnung im Kampf gegen die Schlafkrankheit NZZ German-speaking Switzerland International 2012
Media relations: print media, online media Möglicher Ansatz zur Bekämpfung der Schlafkrankheit entdeckt Pressemitteilung German-speaking Switzerland International 2012

Awards

Title Year
Dr. Lutz Zwillenberg Preis der Universität Bern 2013
29th Swiss Trypanosomatid Meeting - Best Oral Presentation 2012
ICBL - Best Poster Award 2010

Associated projects

Number Title Start Funding scheme
139231 Advancement of functional genomics research at the University of Bern by extension of LC-MS platform 01.07.2012 R'EQUIP
149353 Mitochondrial lipid synthesis in the model eukaryote, Trypanosoma brucei: identification of lipid biosynthesis complexes and contributions of individual pathways to mitochondrial structure and function 01.11.2013 Project funding (Div. I-III)
141913 Transporters of Trypanosoma brucei: Phylogeny - Physiology - Pharmacology 01.06.2013 Sinergia
127300 Functional genomics of nutrient transporters in Trypanosoma brucei: From physiology to pharmacology 01.01.2010 Sinergia
116627 Analysis of novel biosynthetic pathways in trypanosoma brucei: ethanolamine incorporation into proteins and lipids 01.07.2007 Project funding (Div. I-III)

Abstract

African trypanosomes are protozoan parasites causing human African sleeping sickness and a related disease, nagana, in animals. Despite the devastating impact of the diseases on human and animal health in rural sub-Saharan Africa, research on trypanosomes has received little recognition among the scientific community for decades. However, the discovery of several important biological phenomena in trypanosomes, such as RNA editing, trans-splicing, glycosylphosphatidylinositol-anchoring and antigenic variation, which were subsequently found to occur in other eukaryotic organisms as well, has changed the attitude towards trypanosomes and they have become a valuable model organism to study basic questions in biology.Because African trypanosomes are human and animal pathogens, research on trypanosomes has often focused on identifying cellular and metabolic events that may have the potential to become drug targets to inhibit parasite proliferation. We decided to focus our research on two aspects in trypanosome biology that have received little attention in the past, the modification of eukaryotic elongation factor 1A (eEF1A) by ethanolamine phosphoglycerol (EPG) and the metabolism of phospholipids in Trypanosoma brucei. Although EPG modification of eEF1A has been discovered more than two decades ago, the pathway for EPG synthesis and attachment to protein, and its functional significance, have remained elusive. We plan to address these questions by introducing eEF1A constructs, containing amino acid point mutations or deletions, into T. brucei procyclic forms to study functional complementation of these mutant proteins and their interactions with other cellular components. In addition, since we recently demonstrated a direct link between EPG modification and phospholipid metabolism, by showing that the ethanolamine moiety of EPG derives from the phospholipid, phosphatidylethanolamine, we plan to identify and characterize selected metabolic pathways involved in phospholipid synthesis in T. brucei. Based on our previously published observation that the parasite mitochondrium is particularly sensitive to changes in lipid composition, we will focus on characterizing the reactions involved in the biosynthesis of cardiolipin, a characteristic and functionally important phospholipid in mitochondria. Our preliminary observation that one reaction in the synthesis of cardiolipin in T. brucei may involve the action of a bacterial-type, rather than eukaryotic-type, enzyme offers the possibility that this pathway may represent a potential drug target against trypanosomes. In addition, since alterations in membrane lipid composition, induced by experimentally interfering with biosynthetic pathways, are expected to cause pleiotropic or lethal effects in T. brucei, our studies will contribute to a better understanding of the general roles of phospholipids in eukaryotes.Together, our studies have the potential to reveal unique, i.e. parasite-specific, pathways for phospholipid synthesis and turnover in T. brucei and, in addition, shed light on the biosynthesis and function of the EPG modification of eEF1A in a eukaryotic model organism.
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