Arabidopsis thaliana expresses two functional isoforms of Arvp, a protein involved in the regulation of cellular lipid homeostasis

Forés, Oriol; Arró, Montserrat; Pahissa, Albert; Ferrero, S.; Germann, Melody; Stukey, Joseph; McDonough, Virginia; Nickels, Joseph T.; Campos, Narciso; Ferrer, Albert

doi:10.1016/j.bbalip.2006.03.025

Cited by 22 publications

(18 citation statements)

References 34 publications

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“…To examine their identity, we cotransfected 1S:GFP with T3RE, which is a Discosoma spp. red fluorescent protein derivative targeted to the ER lumen (Forés et al, 2006). In N. benthamiana, Arabidopsis, and onion epidermal cells, there was a perfect match between 1S:GFP and T3RE fluorescence in the ER network, nuclear envelope, and spherical structures (Fig.…”

Section: Resultsmentioning

confidence: 99%

Proliferation and Morphogenesis of the Endoplasmic Reticulum Driven by the Membrane Domain of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase in Plant Cells

et al. 2015

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The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) has a key regulatory role in the mevalonate pathway for isoprenoid biosynthesis and is composed of an endoplasmic reticulum (ER)-anchoring membrane domain with low sequence similarity among eukaryotic kingdoms and a conserved cytosolic catalytic domain. Organized smooth endoplasmic reticulum (OSER) structures are common formations of hypertrophied tightly packed ER membranes devoted to specific biosynthetic and secretory functions, the biogenesis of which remains largely unexplored. We show that the membrane domain of plant HMGR suffices to trigger ER proliferation and OSER biogenesis. The proliferating membranes become highly enriched in HMGR protein, but they do not accumulate sterols, indicating a morphogenetic rather than a metabolic role for HMGR. The N-terminal MDVRRRPP motif present in most plant HMGR isoforms is not required for retention in the ER, which was previously proposed, but functions as an ER morphogenic signal. Plant OSER structures are morphologically similar to those of animal cells, emerge from tripartite ER junctions, and mainly build up beside the nuclear envelope, indicating conserved OSER biogenesis in high eukaryotes. Factors other than the OSER-inducing HMGR construct mediate the tight apposition of the proliferating membranes, implying separate ER proliferation and membrane association steps. Overexpression of the membrane domain of Arabidopsis (Arabidopsis thaliana) HMGR leads to ER hypertrophy in every tested cell type and plant species, whereas the knockout of the HMG1 gene from Arabidopsis, encoding its major HMGR isoform, causes ER aggregation at the nuclear envelope. Our results show that the membrane domain of HMGR contributes to ER morphogenesis in plant cells.

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Section: Resultsmentioning

confidence: 99%

Proliferation and Morphogenesis of the Endoplasmic Reticulum Driven by the Membrane Domain of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase in Plant Cells

et al. 2015

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“…Plasmids coding for the different GFP-SQS1 fusions were co-introduced together with plasmid pT3RE, which codes for an ER-targeted variant of the Discosoma red fluorescent protein (DsRed.T3), into onion epidermal cells by micro-bombardment. Onion pieces were kept in darkness at 22°C for 16 h and epidermal cells were examined by laser confocal-scanning fluorescence microscopy as described (Forés et al 2006).…”

Section: Antibody Production and Western Blot Analysismentioning

confidence: 99%

Arabidopsis thaliana contains a single gene encoding squalene synthase

et al. 2008

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Squalene synthase (SQS) catalyzes the condensation of two molecules of farnesyl diphosphate (FPP) to produce squalene (SQ), the first committed precursor for sterol, brassinosteroid, and triterpene biosynthesis. Arabidopsis thaliana contains two SQS-annotated genomic sequences, At4g34640 (SQS1) and At4g34650 (SQS2), organized in a tandem array. Here we report that the SQS1 gene is widely expressed in all tissues throughout plant development, whereas SQS2 is primarily expressed in the vascular tissue of leaf and cotyledon petioles, and the hypocotyl of seedlings. Neither the complete A. thaliana SQS2 protein nor the chimeric SQS resulting from the replacement of the 69 C-terminal residues of SQS2 by the 111 C-terminal residues of the Schizosaccharomyces pombe SQS were able to confer ergosterol prototrophy to a Saccharomyces cerevisiae erg9 mutant strain lacking SQS activity. A soluble form of SQS2 expressed in Escherichia coli and purified was unable to synthesize SQ from FPP in the presence of NADPH and either Mg2+ or Mn2+. These results demonstrated that SQS2 has no SQS activity, so that SQS1 is the only functional SQS in A. thaliana. Mutational studies revealed that the lack of SQS activity of SQS2 cannot be exclusively attributed to the presence of an unusual Ser replacing the highly conserved Phe at position 287. Expression of green fluorescent protein (GFP)-tagged versions of SQS1 in onion epidermal cells demonstrated that SQS1 is targeted to the endoplasmic reticulum (ER) membrane and that this location is exclusively dependent on the presence of the SQS1 C-terminal hydrophobic trans-membrane domain.

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“…The ARV1-encoded pathway was first identified in yeast as essential in cells lacking sterol esterification due to deletions in the two acyl-coenzyme A cholesterol acyltransferase-related enzymes, ARE1 and ARE2. Orthologs of yeast ARV1 have been identified in all eukaryotic organisms queried thus far (33)(34)(35). We describe here studies that implicate the ARV1 gene product as a modulator of cellular fatty acid levels, a process that plays a role in progression of many lipotoxic diseases.…”

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confidence: 97%

A Functional, Genome-wide Evaluation of Liposensitive Yeast Identifies the “RE2 Required for Viability” (ARV1) Gene Product as a Major Component of Eukaryotic Fatty Acid Resistance

Ruggles

Garbarino

Liu

et al. 2014

Journal of Biological Chemistry

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Background: Obesity-related diseases result from accumulation of lipids in nonadipose tissues. Results: Mutations in 167 yeast genes confer fatty acid sensitivity. Loss of yeast and mammalian ARV1 results in pronounced lipid hypersensitivity, lipoapoptosis, and reduced triglyceride synthesis. Conclusion: 75 evolutionarily conserved components of obesity-related disorders were identified. Significance: Understanding lipid sensitivity may lead to treatment of numerous human metabolic diseases.

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Arabidopsis thaliana expresses two functional isoforms of Arvp, a protein involved in the regulation of cellular lipid homeostasis

Cited by 22 publications

References 34 publications

Proliferation and Morphogenesis of the Endoplasmic Reticulum Driven by the Membrane Domain of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase in Plant Cells

Proliferation and Morphogenesis of the Endoplasmic Reticulum Driven by the Membrane Domain of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase in Plant Cells

Arabidopsis thaliana contains a single gene encoding squalene synthase

A Functional, Genome-wide Evaluation of Liposensitive Yeast Identifies the “RE2 Required for Viability” (ARV1) Gene Product as a Major Component of Eukaryotic Fatty Acid Resistance

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