Oleosin Is Bifunctional Enzyme That Has Both Monoacylglycerol Acyltransferase and Phospholipase Activities

Parthibane, Velayoudame; Rajakumari, Sona; Venkateshwari, Varadarajan; Ramachandiran, Iyappan; Rajasekharan, Ram

doi:10.1074/jbc.m111.309955

Cited by 98 publications

(74 citation statements)

References 36 publications

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“…d-SL2 oleosin, which is amphipathic and contains a hydrophobic hairpin, may act as a fortuitous lipid-binding mediator in transformed yeast cells in vivo and in microsomes in vitro, such that an intrinsic membraneassociated acyltransferase or phospholipase is activated and/or has its substrate specificity modified. This hypothetical mediator activity could be altered when the HX 4 D motif or the N-or C-terminal peptide was removed or after phosphorylation (Parthibane et al, 2012a(Parthibane et al, , 2012b. A demonstration that Arachis.d-SL2 oleosin alone on artificial LDs or liposomes has bifunctional activities of acyltransferase and phospholipase would eliminate the mediator possibility.…”

Section: Oleosin Transcripts Are Present In Fruit Mesocarp Of Avocadomentioning

confidence: 99%

“…Conversely, oleosins could act only as a physical barrier preventing LDs from contacting lipase and glyoxysomes until germination and only after they have been phosphorylated or proteolyzed (Parthibane et al, 2012a;Deruyffelaere et al, 2015). Recently, a peanut oleosin (named OLE3 then and Arach.d-SL2 here) was shown to be a bifunctional enzyme exhibiting oleoyl-CoA:monoacylglycerol acyltransferase and phosphatidylcholine acylhydrolase (phospholipase) activities in transformed quadruple mutant yeast (Saccharomyces cerevisiae) in vivo or in isolated microsomes (Parthibane et al, 2012b). The peanut oleosin has the major motifs of HX 4 D of acyltransferases and GXSXG of lipases.…”

Section: Oleosin Transcripts Are Present In Fruit Mesocarp Of Avocadomentioning

confidence: 99%

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Bioinformatics Reveal Five Lineages of Oleosins and the Mechanism of Lineage Evolution Related to Structure/Function from Green Algae to Seed Plants

Huang

2015

Plant Physiol.

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Plant cells contain subcellular lipid droplets with a triacylglycerol matrix enclosed by a layer of phospholipids and the small structural protein oleosin. Oleosins possess a conserved central hydrophobic hairpin of approximately 72 residues penetrating into the lipid droplet matrix and amphipathic amino-and carboxyl (C)-terminal peptides lying on the phospholipid surface. Bioinformatics of 1,000 oleosins of green algae and all plants emphasizing biological implications reveal five oleosin lineages: primitive (in green algae, mosses, and ferns), universal (U; all land plants), and three in specific organs or phylogenetic groups, termed seed low-molecular-weight (SL; seed plants), seed high-molecular-weight (SH; angiosperms), and tapetum (T; Brassicaceae) oleosins. Transition from one lineage to the next is depicted from lineage intermediates at junctions of phylogeny and organ distributions. Within a species, each lineage, except the T oleosin lineage, has one to four genes per haploid genome, only approximately two of which are active. Primitive oleosins already possess all the general characteristics of oleosins. U oleosins have C-terminal sequences as highly conserved as the hairpin sequences; thus, U oleosins including their C-terminal peptide exert indispensable, unknown functions. SL and SH oleosin transcripts in seeds are in an approximately 1:1 ratio, which suggests the occurrence of SL-SH oleosin dimers/multimers. T oleosins in Brassicaceae are encoded by rapidly evolved multitandem genes for alkane storage and transfer. Overall, oleosins have evolved to retain conserved hairpin structures but diversified for unique structures and functions in specific cells and plant families. Also, our studies reveal oleosin in avocado (Persea americana) mesocarp and no acyltransferase/lipase motifs in most oleosins.

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Section: Oleosin Transcripts Are Present In Fruit Mesocarp Of Avocadomentioning

confidence: 99%

Section: Oleosin Transcripts Are Present In Fruit Mesocarp Of Avocadomentioning

confidence: 99%

Bioinformatics Reveal Five Lineages of Oleosins and the Mechanism of Lineage Evolution Related to Structure/Function from Green Algae to Seed Plants

Huang

2015

Plant Physiol.

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“…These four proteins have signifi cant differences as compared with the LPCAT activity of Prdx6. by guest, on May 11, 2018 www.jlr.org Downloaded from ( 49 ). Oleosin contains acyl transferase and lipase motifs, as described for Prdx6, but appears to be involved predominantly in the pathway for synthesis of neutral lipids rather than phospholipids .…”

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confidence: 99%

A novel lysophosphatidylcholine acyl transferase activity is expressed by peroxiredoxin 6

Fisher

Dodia

Sorokina

et al. 2016

Journal of Lipid Research

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as short chain hydroperoxides) using GSH as an electron donor and for hydrolysis of phospholipids; i.e., it exhibits both GSH peroxidase (GPx) and phospholipase A 2 (PLA 2 ) activities ( 1 ). These activities require the binding of Prdx6 to phospholipids in a specifi c orientation in relation to cys47, the active site for GPx activity, and to S32-H26-D140, the catalytic triad for PLA 2 activity ( 2, 3 ). The GPx activity of Prdx6 plays a key role in the antioxidant defense of the lung, as well as other organs ( 4-8 ), and has been shown recently to participate in the repair of peroxidized cell membranes by reduction of phospholipid hydroperoxides ( 3, 9 ). The PLA 2 activity of Prdx6 also participates in the repair of peroxidized cell membranes by liberating the sn -2 oxidized fatty acid to generate lysophosphatidylcholine (LPC) ( 9, 10 ). Additionally, the PLA 2 activity participates in the turnover of lung surfactant phospholipids with a major function in phospholipid remodeling to generate the dipalmitoylphosphatidylcholine (DPPC) that is the surface-active lipid component of the lung surfactant (11)(12)(13)(14)(15). Both the repair of peroxidized cell membrane phospholipids and a pathway for DPPC synthesis require the combined activity of PLA 2 followed by a LPC acyl transferase (LPCAT) activity in order to either regenerate a reduced membrane phospholipid or to remodel phosphatidylcholine (PC) to produce DPPC . This pathway that combines PLA 2 activity followed by LPCAT activity has been designated as the remodeling pathway for PC synthesis (Lands cycle) ( 16 ).These metabolic functions of PLA 2 that are associated with phospholipid turnover and membrane repair are clearly compartmentalized within cells. While DPPC synthesis via the de novo (Kennedy) pathway occurs in the Peroxiredoxin (Prdx)6 is a 1-cys member of the Prdx family that has the unique combination of activities for both reduction of phospholipid hydroperoxides (as well

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“…It is generally agreed that oleosins cover the OB surface, with their central hydrophobic domain inserted in the TAG through the phospholipid layer . Besides their structural function in OBs, oleosins may serve as docking stations for other proteins at its surface and may participate in the biosynthesis and mobilization of plant oils (Parthibane et al, 2012a(Parthibane et al, , 2012b. Oleosins are probably involved in OB stability (Leprince et al, 1998;Shimada et al, 2008) and in the regulation of OB repulsion (Heneen et al, 2008), preventing the coalescence of OBs into a single organelle (Schmidt and Herman, 2008).…”

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confidence: 99%

Specialization of Oleosins in Oil Body Dynamics during Seed Development in Arabidopsis Seeds

et al. 2014

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Oil bodies (OBs) are seed-specific lipid storage organelles that allow the accumulation of neutral lipids that sustain plantlet development after the onset of germination. OBs are covered with specific proteins embedded in a single layer of phospholipids. Using fluorescent dyes and confocal microscopy, we monitored the dynamics of OBs in living Arabidopsis (Arabidopsis thaliana) embryos at different stages of development. Analyses were carried out with different genotypes: the wild type and three mutants affected in the accumulation of various oleosins (OLE1, OLE2, and OLE4), three major OB proteins. Image acquisition was followed by a detailed statistical analysis of OB size and distribution during seed development in the four dimensions (x, y, z, and t). Our results indicate that OB size increases sharply during seed maturation, in part by OB fusion, and then decreases until the end of the maturation process. In single, double, and triple mutant backgrounds, the size and spatial distribution of OBs are modified, affecting in turn the total lipid content, which suggests that the oleosins studied have specific functions in the dynamics of lipid accumulation.The seed is a complex, specific structure that allows a quiescent plant embryo to cope with unfavorable germinating conditions and also permits dissemination of the species. To achieve these functions, seeds accumulate reserve compounds that will ensure the survival of the embryo and fuel the growth of the plantlet upon germination. Accumulation of lipids occurs in many eukaryotic cells and is a rather common means of storing carbon and energy. Lipid droplets (LDs) can be found in all eukaryotes, such as yeast (Saccharomyces cerevisiae;

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Oleosin Is Bifunctional Enzyme That Has Both Monoacylglycerol Acyltransferase and Phospholipase Activities

Cited by 98 publications

References 36 publications

Bioinformatics Reveal Five Lineages of Oleosins and the Mechanism of Lineage Evolution Related to Structure/Function from Green Algae to Seed Plants

Bioinformatics Reveal Five Lineages of Oleosins and the Mechanism of Lineage Evolution Related to Structure/Function from Green Algae to Seed Plants

A novel lysophosphatidylcholine acyl transferase activity is expressed by peroxiredoxin 6

Specialization of Oleosins in Oil Body Dynamics during Seed Development in Arabidopsis Seeds

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