title: Proteome analysis of cytoplasmatic and plastidic β-carotene lipid droplets in Dunaliella bardawil.
abstract: The halotolerant green alga Dunaliella bardawil is unique in that it accumulates under stress two types of lipid droplets: cytoplasmatic lipid droplets (CLD) and β-carotene-rich (βC) plastoglobuli. Recently, we isolated and analyzed the lipid and pigment compositions of these lipid droplets. Here, we describe their proteome analysis. A contamination filter and an enrichment filter were utilized to define core proteins. A proteome database of Dunaliella salina/D. bardawil was constructed to aid the identification of lipid droplet proteins. A total of 124 and 42 core proteins were identified in βC-plastoglobuli and CLD, respectively, with only eight common proteins. Dunaliella spp. CLD resemble cytoplasmic droplets from Chlamydomonas reinhardtii and contain major lipid droplet-associated protein and enzymes involved in lipid and sterol metabolism. The βC-plastoglobuli proteome resembles the C. reinhardtii eyespot and Arabidopsis (Arabidopsis thaliana) plastoglobule proteomes and contains carotene-globule-associated protein, plastid-lipid-associated protein-fibrillins, SOUL heme-binding proteins, phytyl ester synthases, β-carotene biosynthesis enzymes, and proteins involved in membrane remodeling/lipid droplet biogenesis: VESICLE-INDUCING PLASTID PROTEIN1, synaptotagmin, and the eyespot assembly proteins EYE3 and SOUL3. Based on these and previous results, we propose models for the biogenesis of βC-plastoglobuli and the biosynthesis of β-carotene within βC-plastoglobuli and hypothesize that βC-plastoglobuli evolved from eyespot lipid droplets.
authors.affiliation: Department of Biological Chemistry (L.D., U.P.), Nancy and Stephen Grand Israel National Center for Personalized Medicine (Y.L.), and Biological Services Unit (S.B.-D.), Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Lital
authors.initials: L
authors.lastname: Davidi
authors.affiliation: Department of Biological Chemistry (L.D., U.P.), Nancy and Stephen Grand Israel National Center for Personalized Medicine (Y.L.), and Biological Services Unit (S.B.-D.), Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Yishai
authors.initials: Y
authors.lastname: Levin
authors.affiliation: Department of Biological Chemistry (L.D., U.P.), Nancy and Stephen Grand Israel National Center for Personalized Medicine (Y.L.), and Biological Services Unit (S.B.-D.), Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Shifra
authors.initials: S
authors.lastname: Ben-Dor
authors.affiliation: Department of Biological Chemistry (L.D., U.P.), Nancy and Stephen Grand Israel National Center for Personalized Medicine (Y.L.), and Biological Services Unit (S.B.-D.), Weizmann Institute of Science, Rehovot 76100, Israel uri.pick@weizmann.ac.il.
authors.forename: Uri
authors.initials: U
authors.lastname: Pick
mesh_terms: D020418:Algal Proteins / Q000032:analysis* / Q000235:genetics; D000460:Chlorophyta / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D003593:Cytoplasm / Q000737:chemistry*; D008055:Lipids / Q000032:analysis; D010802:Phylogeny; D018087:Plastids / Q000737:chemistry*; D020543:Proteome / Q000032:analysis*; D017421:Sequence Analysis; D019207:beta Carotene / Q000032:analysis* / Q000096:biosynthesis
chemical_list: D020418:Algal Proteins; D008055:Lipids; D020543:Proteome; D019207:beta Carotene