101
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Chen JC, Tzen JT. An in vitro system to examine the effective phospholipids and structural domain for protein targeting to seed oil bodies. PLANT & CELL PHYSIOLOGY 2001; 42:1245-52. [PMID: 11726710 DOI: 10.1093/pcp/pce160] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
An in vitro system was established to examine the targeting of proteins to maturing seed oil bodies. Oleosin, the most abundant structural protein, and caleosin, a newly identified minor constituent in seed oil bodies, were translated in a reticulocyte lysate system and simultaneously incubated with artificial oil emulsions composed of triacylglycerol and phospholipid. The results suggest that oil body proteins could spontaneously target to artificial oil emulsions in a co-translational mode. Incorporation of oleosin to artificial oil emulsions extensively protected a fragment of approximately 8 kDa from proteinase K digestion. In a competition experiment, in vitro translated caleosin and oleosin preferentially target to artificial oil emulsions instead of microsomal membranes. In oil emulsions with neutral phospholipids, relatively low protein targeting efficiency was observed. The targeting efficiency was substantially elevated when negatively charged phospholipids were supplemented to oil emulsions to mimic the native phospholipid composition of oil bodies. Mutated caleosin lacking various structural domains or subdomains was examined for its in vitro targeting efficiency. The results indicate that the subdomain comprising the proline knot motif is crucial for caleosin targeting to oil bodies. A model of direct targeting of oil-body proteins to maturing oil bodies is proposed.
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Affiliation(s)
- J C Chen
- Graduate Institute of Agricultural Biotechnology, National Chung-Hsing University, Taichung, Taiwan
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102
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Ostermeyer AG, Paci JM, Zeng Y, Lublin DM, Munro S, Brown DA. Accumulation of caveolin in the endoplasmic reticulum redirects the protein to lipid storage droplets. J Cell Biol 2001; 152:1071-8. [PMID: 11238461 PMCID: PMC2198801 DOI: 10.1083/jcb.152.5.1071] [Citation(s) in RCA: 206] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Caveolin-1 is normally localized in plasma membrane caveolae and the Golgi apparatus in mammalian cells. We found three treatments that redirected the protein to lipid storage droplets, identified by staining with the lipophilic dye Nile red and the marker protein ADRP. Caveolin-1 was targeted to the droplets when linked to the ER-retrieval sequence, KKSL, generating Cav-KKSL. Cav-DeltaN2, an internal deletion mutant, also accumulated in the droplets, as well as in a Golgi-like structure. Third, incubation of cells with brefeldin A caused caveolin-1 to accumulate in the droplets. This localization persisted after drug washout, showing that caveolin-1 was transported out of the droplets slowly or not at all. Some overexpressed caveolin-2 was also present in lipid droplets. Experimental reduction of cellular cholesteryl ester by 80% did not prevent targeting of Cav-KKSL to the droplets. Cav-KKSL expression did not grossly alter cellular triacylglyceride or cholesteryl levels, although droplet morphology was affected in some cells. These data suggest that accumulation of caveolin-1 to unusually high levels in the ER causes targeting to lipid droplets, and that mechanisms must exist to ensure the rapid exit of newly synthesized caveolin-1 from the ER to avoid this fate.
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Affiliation(s)
- Anne G. Ostermeyer
- Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, Stony Brook, New York 11794
| | - James M. Paci
- Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, Stony Brook, New York 11794
| | - Youchun Zeng
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Douglas M. Lublin
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Sean Munro
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 2QH, United Kingdom
| | - Deborah A. Brown
- Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, Stony Brook, New York 11794
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103
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Girke T, Todd J, Ruuska S, White J, Benning C, Ohlrogge J. Microarray analysis of developing Arabidopsis seeds. PLANT PHYSIOLOGY 2000; 124:1570-81. [PMID: 11115875 PMCID: PMC59856 DOI: 10.1104/pp.124.4.1570] [Citation(s) in RCA: 213] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2000] [Revised: 06/20/2000] [Accepted: 09/13/2000] [Indexed: 05/18/2023]
Abstract
To provide a broad analysis of gene expression in developing Arabidopsis seeds, microarrays have been produced that display approximately 2,600 seed-expressed genes. DNA for genes spotted on the arrays were selected from >10,000 clones partially sequenced from a cDNA library of developing seeds. Based on a series of controls, sensitivity of the arrays was estimated at one to two copies of mRNA per cell and cross hybridization was estimated to occur if closely related genes have >70% to 80% sequence identity. These arrays have been hybridized in a series of experiments with probes derived from seeds, leaves, and roots of Arabidopsis. Analysis of expression ratios between the different tissues has allowed the tissue-specific expression patterns of many hundreds of genes to be described for the first time. Approximately 25% of the 2, 600 genes were expressed at ratios > or =2-fold higher in seeds than leaves or roots and 10% at ratios > or =10. Included in this list are a large number of proteins of unknown function, and potential regulatory factors such as protein kinases, phosphatases, and transcription factors. The Arabidopsis arrays were also found to be useful for transcriptional profiling of mRNA isolated from developing oilseed rape (Brassica napus) seeds and expression patterns correlated well between the two species.
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Affiliation(s)
- T Girke
- Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan 48824, USA
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104
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Naested H, Frandsen GI, Jauh GY, Hernandez-Pinzon I, Nielsen HB, Murphy DJ, Rogers JC, Mundy J. Caleosins: Ca2+-binding proteins associated with lipid bodies. PLANT MOLECULAR BIOLOGY 2000; 44:463-76. [PMID: 11197322 DOI: 10.1023/a:1026564411918] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We have previously identified a rice gene encoding a 27 kDa protein with a single Ca2+-binding EF-hand and a putative membrane anchor. We report here similar genes termed caleosins, CLO, in other plants and fungi; they comprise a multigene family of at least five members in Arabidopsis (AtClo1-5). Northern hybridization demonstrated that AtClo2-4 mRNAs levels were low in various tissues, while AtClo1 mRNA levels were high in developing embryos and mature seeds. Analysis of transgenic Arabidopsis plants expressing the GUS reporter under control of the AtClo1 promoter showed strong levels of expression in developing embryos and also in root tip cells. Antibodies raised against AtCLO1 were used to detect caleosin in cellular fractions of Arabidopsis and rapeseed. This indicated that caleosins are a novel class of lipid body proteins, which may also be associated with an ER subdomain.
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Affiliation(s)
- H Naested
- Institute of Molecular Biology, Oester Farimagsgade 2A, Copenhagen, Denmark
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105
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Zweytick D, Athenstaedt K, Daum G. Intracellular lipid particles of eukaryotic cells. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1469:101-20. [PMID: 10998572 DOI: 10.1016/s0005-2736(00)00294-7] [Citation(s) in RCA: 260] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this review article we describe characterization of intracellular lipid particles of three different eukaryotic species, namely mammalian cells, plants and yeast. Lipid particles of all types of cells share a general structure. A hydrophobic core of neutral lipids is surrounded by a membrane monolayer of phospholipids which contains a minor amount of proteins. Whereas lipid particles from mammalian cells and plants harbor specific classes of polypeptides, mainly perilipins and oleosins, respectively, yeast lipid particles contain a more complex set of enzymes which are involved in lipid biosynthesis. Function of lipid particles as storage compartment and metabolic organelle, and their interaction with other subcellular fractions are discussed. Furthermore, models for the biogenesis of lipid particles are presented and compared among the different species.
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Affiliation(s)
- D Zweytick
- Institut für Biochemie und Lebensmittelchemie, Technische Universität, Petersgasse 12/II, A-8010, Graz, Austria
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106
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Weselake RJ, Taylor DC. The study of storage lipid biosynthesis using microspore-derived cultures of oil seed rape. Prog Lipid Res 1999; 38:401-60. [PMID: 10793890 DOI: 10.1016/s0163-7827(99)00011-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- R J Weselake
- Department of Chemistry and Biochemistry, University of Lethbridge, Alberta, Canada.
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107
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Abstract
Vegetable oils are a major component of human diets, comprising as much as 25% of average caloric intake. Until recently, it was not possible to exert significant control over the chemical composition of vegetable oils derived from different plants. However, the advent of genetic engineering has provided novel opportunities to tailor the composition of plant-derived lipids so that they are optimized with respect to food functionality and human dietary needs. In order to exploit this new capability, it is essential for food scientists and nutritionists to define the lipid compositions that would be most desirable for various purposes.
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Affiliation(s)
- P Broun
- Mendel Biotechnology, Hayward, California 94545, USA.
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108
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Cramer CL, Boothe JG, Oishi KK. Transgenic plants for therapeutic proteins: linking upstream and downstream strategies. Curr Top Microbiol Immunol 1999; 240:95-118. [PMID: 10394717 DOI: 10.1007/978-3-642-60234-4_5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We have described two very different and innovative plant-based production systems--postharvest production and recovery of recombinant product from tobacco leaves using an inducible promoter and oleosin-mediated recovery of recombinant product from oilseeds using a seed-specific promoter. Both base technologies are broadly applicable to numerous classes of pharmaceutical and industrial proteins. As with any emerging technology, the key to success may lie in identifying those products and applications that would most benefit from the unique advantages offered by each system. The postharvest tobacco leaf system appears effective for proteins requiring complex posttranslational processing and endomembrane targeting. Because of the remarkable fecundity and biomass production capacity of tobacco, biomass scale-up is very rapid and production costs are low. Clearly the development of equally cost-effective extraction and purification technologies will be critical for full realization of the commercial opportunities afforded by transgenic plant-based bioproduction. The recovery of protein from tobacco leaves or oleosin-partitioned proteins by oil-body separations represent significant break-throughs for cost-effective commercialization strategies. Additional low-cost, high-affinity separation technologies need to be developed for effective scale-up purification of plant-synthesized recombinant proteins. Clearly successful commercialization of plant-synthesized biopharmaceuticals must effectively link upstream strategies involving gene and protein design with downstream strategies for reproducible GMP-level recovery of bioactive recombinant protein. Both the tobacco and oilseed systems are uniquely designed to address issues of biomass storage, product recovery, quality assurance, and regulatory scrutiny in addition to issues of transgene expression and protein processing.
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Affiliation(s)
- C L Cramer
- CropTech Corp., Virginia Tech Corporate Research Center, Blacksburg 24060, USA
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109
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Abstract
Most organisms transport or store neutral lipids as lipid bodies - lipid droplets that usually are bounded by specific proteins and (phospho)lipid. Neutral-lipid bodies vary considerably in their morphology and are associated with an extremely diverse range of proteins. However, the mechanisms by which they are generated in plants, animals and microorganisms appear to share many common features: lipid bodies probably arise from microdomains of the endoplasmic reticulum (or the plasma membrane in prokaryotes) that contain lipid-biosynthesis enzymes, and their synthesis and size appear to be controlled by specific protein components.
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Affiliation(s)
- D J Murphy
- Dept of Brassica and Oilseeds Research, John Innes Centre, Norwich Research Park, Norwich, UK NR4 7UH.
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110
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Galili G, Sengupta-Gopalan C, Ceriotti A. The endoplasmic reticulum of plant cells and its role in protein maturation and biogenesis of oil bodies. PLANT MOLECULAR BIOLOGY 1998. [PMID: 9738958 DOI: 10.1023/a:1006011919671] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The endoplasmic reticulum (ER) is the port of entry of proteins into the endomembrane system, and it is also involved in lipid biosynthesis and storage. This organelle contains a number of soluble and membrane-associated enzymes and molecular chaperones, which assist the folding and maturation of proteins and the deposition of lipid storage compounds. The regulation of translocation of proteins into the ER and their subsequent maturation within the organelle have been studied in detail in mammalian and yeast cells, and more recently also in plants. These studies showed that in general the functions of the ER in protein synthesis and maturation have been highly conserved between the different organisms. Yet, the ER of plants possesses some additional functions not found in mammalian and yeast cells. This compartment is involved in cell to cell communication via the plasmodesmata, and, in specialized cells, it serves as a storage site for proteins. The plant ER is also equipped with enzymes and structural proteins which are involved in the process of oil body biogenesis and lipid storage. In this review we discuss the components of the plant ER and their function in protein maturation and biogenesis of oil bodies. Due to the large number of cited papers, we were not able to cite all individual references and in many cases we refer the readers to reviews and references therein. We apologize to the authors whose references are not cited.
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Affiliation(s)
- G Galili
- Department of Plant Sciences, The Weizmann Institute of Science, Rehovot, Israel
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111
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Boothe JG, Saponja JA, Parmenter DL. Molecular farming in plants: Oilseeds as vehicles for the production of pharmaceutical proteins. Drug Dev Res 1997. [DOI: 10.1002/(sici)1098-2299(199711/12)42:3/4<172::aid-ddr9>3.0.co;2-n] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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