Flagellar membranes are rich in raft-forming phospholipids.
The observation that the membranes of flagella are enriched in sterols and sphingolipids has led to the hypothesis that flagella might be enriched in raft-forming lipids. However, a detailed lipidomic analysis of flagellar membranes is not available. Novel protocols to detach and isolate intact flagella from Trypanosoma brucei procyclic forms in combination with reverse-phase liquid chromatography high-resolution tandem mass spectrometry allowed us to determine the phospholipid composition of flagellar membranes relative to whole cells. Our analyses revealed that phosphatidylethanolamine, phosphatidylserine, ceramide and the sphingolipids inositol phosphorylceramide and sphingomyelin are enriched in flagella relative to whole cells. In contrast, phosphatidylcholine and phosphatidylinositol are strongly depleted in flagella. Within individual glycerophospholipid classes, we observed a preference for ether-type over diacyl-type molecular species in membranes of flagella. Our study provides direct evidence for a preferential presence of raft-forming phospholipids in flagellar membranes of T. brucei.
Institute of Biochemistry & Molecular Medicine, University of Bern, Bern 3012, Switzerland peter.buetikofer@ibmm.unibe.ch mauro.serricchio@utoronto.ca.
Mauro
M
Serricchio
Proteomics Core Facility, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland.
Adrien W
AW
Schmid
Institute of Biochemistry & Molecular Medicine, University of Bern, Bern 3012, Switzerland.
Michael E
ME
Steinmann
Institute of Biochemistry & Molecular Medicine, University of Bern, Bern 3012, Switzerland.
Erwin
E
Sigel
Institute of Biochemistry & Molecular Medicine, University of Bern, Bern 3012, Switzerland.
Monika
M
Rauch
Trypanosome Cell Biology Unit, Pasteur Institute and INSERM U1201, Paris 75015, France.
Daria
D
Julkowska
Trypanosome Cell Biology Unit, Pasteur Institute and INSERM U1201, Paris 75015, France.
Serge
S
Bonnefoy
Trypanosome Cell Biology Unit, Pasteur Institute and INSERM U1201, Paris 75015, France.
Cécile
C
Fort
Trypanosome Cell Biology Unit, Pasteur Institute and INSERM U1201, Paris 75015, France.
Philippe
P
Bastin
Institute of Biochemistry & Molecular Medicine, University of Bern, Bern 3012, Switzerland peter.buetikofer@ibmm.unibe.ch mauro.serricchio@utoronto.ca.
Peter
P
Bütikofer
Flagella; Lipid rafts; Mass spectrometry; Membrane lipids; Sphingolipids; Trypanosoma brucei