A phospholipase A2 is transiently synthesized during seed germination and localized to lipid bodies

Christian, May; Preisig‐Müller, Regina; Höhne, Michaela; Gnau, Petra; Kindl, Helmut

doi:10.1016/s0005-2760(98)00081-2

Cited by 50 publications

(59 citation statements)

References 28 publications

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“…It contains a 168-amino-acid-long PATATIN domain, which is common to a family of plant seed storage proteins that have phospholipase and esterase activity (16). One family member is a lipid droplet-associated phospholipase A2 involved in plant seed fat mobilization (17). Adiponutrin, a recently identified adipocyte-specific membrane protein (18), also has a PATATIN domain.…”

Section: Resultsmentioning

confidence: 99%

Chinese Hamster Ovary K2 Cell Lipid Droplets Appear to Be Metabolic Organelles Involved in Membrane Traffic

Liu¹,

Ying²,

Zhao

et al. 2004

Journal of Biological Chemistry

476

487

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The principal lipids in animal cell lipid droplets are cholesterol, cholesterol ester, and triglyceride, but the protein composition of this compartment is largely unknown. Here we report on the proteomic analysis of lipid droplets. Using a combination of mass spectrometry and immunoblotting, we identify nearly 40 specifically associated proteins in droplets isolated from Chinese hamster ovary K2 cells grown in normal medium. The proteins fall in to five groups: structural molecules of the droplet-like adipose differentiation-related protein; multiple enzymes involved in the synthesis, storage, utilization, and degradation of cholesterol esters and triglycerides; multiple, different Rab GTPases known to be involved in regulating membrane traffic; signaling molecules such as p50RhoGAP; and a group of proteins that do not fit any classification but include proteins often found in caveolae/rafts such as caveolin-1 and 2 and flotillin-1. The proteome of droplets isolated from cells grown in the presence of oleate is largely the same except for an increase in the amount of adipose differentiation-related protein, caveolin-1, and a protein thought to be involved in phospholipid recycling called CGI-58. Based on the protein profile, the lipid droplet appears to be a complex, metabolically active organelle that is directly involved in membrane traffic and possibly phospholipid recycling. We propose the name adiposome for this organelle.Lipid droplets are generally regarded as simple storage depots for neutral lipids in animal and plant cells. Their morphologic appearance gives the impression they are inert cellular inclusions that derive metabolic sustenance solely from their association with smooth endoplasmic reticulum, mitochondria, or peroxisomes (1). This is especially true in professional fat storing cells of plant seeds and adipose tissue where they occupy much of the cytoplasmic space.Plant and animal lipid droplets are coated with proteins that may regulate their size. Plant oleosins, a large family of structurally related proteins, form a capsule around seed lipid bodies (2). By contrast, a family of four proteins (ADRP, 1 perilipin, S3-12, and TIP47) that share a 100-amino-acid-long region of homology at the N terminus called the PAT domain are associated with the periphery of animal lipid droplets (3). ADRP, perilipin, and S3-12 are expressed highly in adipocytes. Unlike perilipin and S3-12, ADRP is expressed ubiquitously. Both the oleosins and the PAT domain proteins may function as barriers that control the lipolysis of core lipids (4). Apparently oleosins and PAT domain proteins are not strictly required for the generation and stability of a lipid droplet because these proteins are not found in yeast (Saccharomyces cerevisiae) lipid droplets (5). Instead, the predominant proteins in the lipid droplet fraction of these cells are enzymes involved in sterol and triglyceride metabolism. The localization of these enzymes to yeast lipid droplets suggests that the droplet is a metabolic organelle with a central ...

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Section: Resultsmentioning

confidence: 99%

Chinese Hamster Ovary K2 Cell Lipid Droplets Appear to Be Metabolic Organelles Involved in Membrane Traffic

Liu¹,

Ying²,

Zhao

et al. 2004

Journal of Biological Chemistry

476

487

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“…Phospholipases A partially destruct the granule phospholipid layer, making lipids accessible for degrading enzymes such as depolymerases, thus allowing PHB metabolization (43). Accordingly, May and coworkers previously demonstrated that a plant PLP of Cucumis sativus specifically localized to lipid granules for support of lipid mobilization during seed germination (37). Whether PatD directly facilitates PHB utilization in L. pneumophila requires further work and will be addressed in future studies.…”

Section: Discussionmentioning

confidence: 99%

bdhA-patD Operon as a Virulence Determinant, Revealed by a Novel Large-Scale Approach for Identification of Legionella pneumophila Mutants Defective for Amoeba Infection

Auraß

Pless

Rydzewski

et al. 2009

Appl Environ Microbiol

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Legionella pneumophila, the causative agent of Legionnaires' disease, is an intracellular parasite of eukaryotic cells. In the environment, it colonizes amoebae. After being inhaled into the human lung, the bacteria infect and damage alveolar cells in a way that is mechanistically similar to the amoeba infection. Several L. pneumophila traits, among those the Dot/Icm type IVB protein secretion machinery, are essential for exploiting host cells. In our search for novel Legionella virulence factors, we developed an agar plate assay, designated the scatter screen, which allowed screening for mutants deficient in infecting Acanthamoeba castellanii amoebae. Likewise, an L. pneumophila clone bank consisting of 23,000 transposon mutants was investigated here, and 19 different established Legionella virulence genes, for example, dot/icm genes, were identified. Importantly, 70 novel virulence-associated genes were found. One of those is L. pneumophila bdhA, coding for a protein with homology to established 3-hydroxybutyrate dehydrogenases involved in poly-3-hydroxybutyrate metabolism. Our study revealed that bdhA is cotranscribed with patD, encoding a patatin-like protein of L. pneumophila showing phospholipase A and lysophospholipase A activities. In addition to strongly reduced lipolytic activities and increased poly-3-hydroxybutyrate levels, the L. pneumophila bdhA-patD mutant showed a severe replication defect in amoebae and U937 macrophages. Our data suggest that the operon is involved in poly-3-hydroxybutyrate utilization and phospholipolysis and show that the bdhA-patD operon is a virulence determinant of L. pneumophila. In summary, the screen for amoeba-sensitive Legionella clones efficiently isolated mutants that do not grow in amoebae and, in the case of the bdhA-patD mutant, also human cells.

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“…The oxylipin products of the octadecanoid pathway, in particular jasmonic acid and methyl jasmonate, regulate a number of cellular processes, including wound and defense responses (Dhondt et al, 2000;Schaller, 2001). Phospholipase A2 is also up-regulated during flower development (Kim et al, 1999;Lee et al, 2003) and, in addition, has been detected in lipid bodies, implicating its involvement in lipid mobilization during seed germination (May et al, 1998). Recently, the DEFECTIVE IN ANTHER DEHISCENCE1 (DAD1) gene in Arabidopsis (Arabidopsis thaliana) has been shown to encode phospholipase A1, an enzyme that catalyzes deesterification of the sn1 fatty acid of phospholipids (Ishiguro et al, 2001).…”

Section: -X-[livafy]-[liamvst]-g-[hywv]-s-x-g-[gstac]mentioning

confidence: 99%

Characterization of a Plastid Triacylglycerol Lipase from Arabidopsis

et al. 2007

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Full-length cDNA corresponding to Arabidopsis (Arabidopsis thaliana) gene At2g31690, which has been annotated in GenBank as a putative triacylglycerol (TAG) lipase, was obtained by reverse transcription-polymerase chain reaction using RNA from senescing rosette leaves of Arabidopsis as a template. The cognate protein was found to contain the lipase active site sequence, and corresponding recombinant protein proved capable of deesterifying TAG. In vitro chloroplast import assays indicated that the lipase is targeted to chloroplasts. This was confirmed by confocal microscopy of rosette leaf tissue treated with fluorescein isocyanate-labeled, lipase-specific antibody, which revealed that lipase protein colocalizes with plastoglobular neutral lipids. Western-blot analysis indicated that the lipase is expressed in roots, inflorescence stems, flowers, siliques, and leaves and that it is strongly up-regulated in senescing rosette leaf tissue. Transgenic plants with suppressed lipase protein levels were obtained by expressing At2g31690 cDNA in antisense orientation under the regulation of a constitutive promoter. Transgenic plants bolted and flowered at the same time as wild-type plants, but were severely stunted and exhibited delayed rosette senescence. Moreover, the stunted growth phenotype correlated with irregular chloroplast morphology. The chloroplasts of transgenic plants were structurally deformed, had reduced abundance of thylakoids that were abnormally stacked, and contained more plastoglobular neutral lipids than chloroplasts of wild-type plants. These observations collectively indicate that this TAG lipase plays a role in maintaining the structural integrity of chloroplasts, possibly by mobilizing the fatty acids of plastoglobular TAG.

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A phospholipase A2 is transiently synthesized during seed germination and localized to lipid bodies

Cited by 50 publications

References 28 publications

Chinese Hamster Ovary K2 Cell Lipid Droplets Appear to Be Metabolic Organelles Involved in Membrane Traffic

Chinese Hamster Ovary K2 Cell Lipid Droplets Appear to Be Metabolic Organelles Involved in Membrane Traffic

bdhA-patD Operon as a Virulence Determinant, Revealed by a Novel Large-Scale Approach for Identification of Legionella pneumophila Mutants Defective for Amoeba Infection

Characterization of a Plastid Triacylglycerol Lipase from Arabidopsis

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