title: Proteomic profiling of oil bodies isolated from the unicellular green microalga Chlamydomonas reinhardtii: with focus on proteins involved in lipid metabolism.
abstract: Oil bodies are sites of energy and carbon storage in many organisms including microalgae. As a step toward deciphering oil accumulation mechanisms in algae, we used proteomics to analyze purified oil bodies from the model microalga Chlamydomonas reinhardtii grown under nitrogen deprivation. Among the 248 proteins (≥ 2 peptides) identified by LC-MS/MS, 33 were putatively involved in the metabolism of lipids (mostly acyl-lipids and sterols). Compared with a recently reported Chlamydomonas oil body proteome, 19 new proteins of lipid metabolism were identified, spanning the key steps of the triacylglycerol synthesis pathway and including a glycerol-3-phosphate acyltransferase (GPAT), a lysophosphatidic acid acyltransferase (LPAT) and a putative phospholipid:diacylglycerol acyltransferase (PDAT). In addition, proteins putatively involved in deacylation/reacylation, sterol synthesis, lipid signaling and lipid trafficking were found to be associated with the oil body fraction. This data set thus provides evidence that Chlamydomonas oil bodies are not only storage compartments but also are dynamic structures likely to be involved in processes such as oil synthesis, degradation and lipid homeostasis. The proteins identified here should provide useful targets for genetic studies aiming at increasing our understanding of triacyglycerol synthesis and the role of oil bodies in microalgal cell functions.
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction of Life Sciences, Institute of Environmental Biology and Biotechnology, CEA Cadarache, Saint-Paul-lez-Durance, France.
authors.forename: Hoa M
authors.initials: HM
authors.lastname: Nguyen
authors.forename: Mathieu
authors.initials: M
authors.lastname: Baudet
authors.forename: Stéphan
authors.initials: S
authors.lastname: Cuiné
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Adriano
authors.forename: Damien
authors.initials: D
authors.lastname: Barthe
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Billon
authors.forename: Christophe
authors.initials: C
authors.lastname: Bruley
authors.forename: Fred
authors.initials: F
authors.lastname: Beisson
authors.forename: Gilles
authors.initials: G
authors.lastname: Peltier
authors.forename: Myriam
authors.initials: M
authors.lastname: Ferro
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Li-Beisson
mesh_terms: D016825:Chlamydomonas reinhardtii / Q000737:chemistry* / Q000378:metabolism; D050356:Lipid Metabolism; D058086:Microalgae / Q000737:chemistry* / Q000378:metabolism; D015388:Organelles / Q000737:chemistry / Q000378:metabolism; D010940:Plant Proteins / Q000032:analysis* / Q000378:metabolism; D020543:Proteome / Q000032:analysis* / Q000378:metabolism; D040901:Proteomics
chemical_list: D010940:Plant Proteins; D020543:Proteome