The phospholipid methyltransferases in yeast

Kanipes, Margaret I.; Henry, Susan A.

doi:10.1016/s0005-2760(97)00121-5

Cited by 57 publications

(46 citation statements)

References 29 publications

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Section: Discussionmentioning

confidence: 99%

“…Three separate enzymes are required to convert P-EA to P-Cho in nerve tissues (9), and two separate enzymes carry out the Ptd-EA 3 Ptd-MME and Ptd-MME 33 Ptd-Cho steps in fungi (7). Fungal Ptd-EA methyltransferases contain regions (Ϸ100 residues) of internal duplication, but the functional significance of this is not known, and these enzymes mediate only one methylation (7). R. sphaeroides and liver have enzymes that mediate all three methylations in Ptd-Cho synthesis, but these are small (22)(23) proteins that appear to have only one methyltransferase domain (6,8).…”

Section: Discussionmentioning

confidence: 99%

“…The cho2 gene product mediates the first of these, Ptd-EA 3 Ptd-MME (Fig. 1B) and cho2 Ϫ mutants require MME, DME, or Cho for growth (7). S. pombe incorporates preformed Cho or other free bases into phospholipids via the CDP base or Kennedy pathway, i.e.…”

Section: Peamt Cloning By Complementation Of a S Pombe Cho2mentioning

confidence: 99%

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cDNA Cloning of PhosphoethanolamineN-Methyltransferase from Spinach by Complementation inSchizosaccharomyces pombe and Characterization of the Recombinant Enzyme

Nuccio¹,

Ziemak²,

Henry³

et al. 2000

Journal of Biological Chemistry

101

139

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The N-methylation of phosphoethanolamine is the committing step in choline biogenesis in plants and is catalyzed by S-adenosyl-L-methionine:phosphoethanolamine N-methyltransferase (PEAMT, EC 2.1.1.103). A spinach PEAMT cDNA was isolated by functional complementation of a Schizosaccharomyces pombe cho2؊ mutant and was shown to encode a protein with PEAMT activity and without ethanolamine-or phosphatidylethanolamine N-methyltransferase activity. The PEAMT cDNA specifies a 494-residue polypeptide comprising two similar, tandem methyltransferase domains, implying that PEAMT arose by gene duplication and fusion. Data base searches suggested that PEAMTs with the same tandem structure are widespread among flowering plants. Size exclusion chromatography of the recombinant enzyme indicates that it exists as a monomer. PEAMT catalyzes not only the first N-methylation of phosphoethanolamine but also the two subsequent N-methylations, yielding phosphocholine. Monomethyl-and dimethylphosphoethanolamine are detected as reaction intermediates. A truncated PEAMT lacking the C-terminal methyltransferase domain catalyzes only the first methylation. Phosphocholine inhibits both the wild type and the truncated enzyme, although the latter is less sensitive. Salinization of spinach plants increases PEAMT mRNA abundance and enzyme activity in leaves by about 10-fold, consistent with the high demand in stressed plants for choline to support glycine betaine synthesis.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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cDNA Cloning of PhosphoethanolamineN-Methyltransferase from Spinach by Complementation inSchizosaccharomyces pombe and Characterization of the Recombinant Enzyme

Nuccio¹,

Ziemak²,

Henry³

et al. 2000

Journal of Biological Chemistry

101

139

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“…The ELO1 gene has two structural and functional homologs in S. cerevisiae, FEN1/ELO2 and SUR4/ELO3. Elo2p is involved in elongation of fatty acids up to C 22 and C 24 , while Elo3p has a broader substrate specificity and is required for conversion of C 24 to C 26 (37). Neither Elo2p nor Elo3p confers essential functions by itself; however, elo2⌬ elo3⌬ double mutants are inviable (37).…”

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confidence: 99%

Tsc13p Is Required for Fatty Acid Elongation and Localizes to a Novel Structure at the Nuclear-Vacuolar Interface in Saccharomyces cerevisiae

Kohlwein

Eder

et al. 2001

Molecular and Cellular Biology

213

245

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The TSC13/YDL015c gene was identified in a screen for suppressors of the calcium sensitivity of csg2⌬ mutants that are defective in sphingolipid synthesis. The fatty acid moiety of sphingolipids in Saccharomyces cerevisiae is a very long chain fatty acid (VLCFA) that is synthesized by a microsomal enzyme system that lengthens the palmitate produced by cytosolic fatty acid synthase by two carbon units in each cycle of elongation. The TSC13 gene encodes a protein required for elongation, possibly the enoyl reductase that catalyzes the last step in each cycle of elongation. The tsc13 mutant accumulates high levels of long-chain bases as well as ceramides that harbor fatty acids with chain lengths shorter than 26 carbons. These phenotypes are exacerbated by the deletion of either the ELO2 or ELO3 gene, both of which have previously been shown to be required for VLCFA synthesis. Compromising the synthesis of malonyl coenzyme A (malonyl-CoA) by inactivating acetyl-CoA carboxylase in a tsc13 mutant is lethal, further supporting a role of Tsc13p in VLCFA synthesis. Tsc13p coimmunoprecipitates with Elo2p and Elo3p, suggesting that the elongating proteins are organized in a complex. Tsc13p localizes to the endoplasmic reticulum and is highly enriched in a novel structure marking nuclear-vacuolar junctions.

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“…For instance, three-step methylation reactions of phosphatidylethanolamine (Ptd-EA), Ptdmonomethyl-EA, and Ptd-dimethyl-EA have been catalyzed by a single Ptd-EA N-methyltransferase in the cases of Rhodobacter sphaeroides and liver (30,31). However, in yeast, these reactions are catalyzed by two enzymes, one mediating the first methylation of Ptd-EA and another mediating the last two (32). In the phospho-base pathway, presence of three separate N-methyltransferases has been reported in nerve tissues (33), whereas in plants, three-step methylation reactions were catalyzed by a single enzyme comprising two similar tandem methyltransferase domains (27).…”

Section: Discussionmentioning

confidence: 99%

Isolation and Functional Characterization ofN-Methyltransferases That Catalyze Betaine Synthesis from Glycine in a Halotolerant Photosynthetic Organism Aphanothece halophytica

Waditee¹,

Tanaka²,

Aoki³

et al. 2003

Journal of Biological Chemistry

116

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Glycine betaine (N,N,N-trimethylglycine) is an important osmoprotectant and is synthesized in response to abiotic stresses. Although almost all known biosynthetic pathways of betaine are two-step oxidation of choline, here we isolated two N-methyltransferase genes from a halotolerant cyanobacterium Aphanothece halophytica. The most known biosynthetic pathways of betaine are the two-step oxidation of choline. Many bacteria, plants, and animals accumulate glycine betaine (here after betaine) under abiotic stress conditions (1-3). In these organisms, it was shown that betaine is synthesized by two steps, choline 3 betaine aldehyde 3 glycine betaine. The enzyme involved in the second step seems to be the same in plants, animals, and bacteria, namely NAD ϩ -dependent betaine-aldehyde dehydrogenase (4 -6). By contrast, different enzymes are involved for the first step. In plants, it was catalyzed by a novel Rieske-type iron-sulfur enzyme choline monooxygenase (7,8). In animals and many bacteria, the first step is catalyzed by membranebound choline dehydrogenase or soluble choline oxidase (9 -11). In some bacteria, choline dehydrogenase and choline oxidase also catalyze the second oxidation step (9 -11).It was suggested that betaine might be synthesized from glycine by a series of methylation reactions in archaebacterium Methanohalophilus portucalensis (12) and anaerobic phototrophic sulfur bacterium Ectothiorhodospira halochloris (13). Betaine synthesis from simple carbon sources has also been suggested in aerobic heterotrophic eubacterium Actinopolyspora halophila (13) and halotolerant cyanobacterium of Aphanothece halophytica (14). Recently, the methyltransferase genes that are involved in betaine synthesis have been isolated from E. halochloris and A. halophila (15). Two methyltransferase genes were involved in E. halochloris. One of gene products catalyzed the methylation reactions of glycine and sarcosine to sarcosine and dimethylglycine, respectively (EcGSMT), 1 whereas the other one catalyzed the methylations of sarcosine and dimethylglycine to dimethylglycine and betaine, respectively (EcSDMT) (15,16). By contrast, one ORF was found in A. halophila of which the N-and C-terminal parts had homologous sequences to those of EcGSMT and EcSDMT, respectively (15). The functionality of A. halophila methyltransferase was not well shown due to the formation of cell pellet when expressed in Escherichia coli.Glycine N-methyltransferase (GMT) catalyzing the methylation of glycine to sarcosine is known in mammalian cells although the enzymes catalyzing the further methylation steps do not occur (17,18). The homology of amino acid sequences between mammalian GMT and EcGSMT was low. No homologous sequences to those of EcGSMT, EcSDMT, and A. halophila methyltransferase could be found. Therefore, it was interesting to examine whether betaine is synthesized from glycine by three-step methylation reactions in other organisms.

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The phospholipid methyltransferases in yeast

Cited by 57 publications

References 29 publications

cDNA Cloning of PhosphoethanolamineN-Methyltransferase from Spinach by Complementation inSchizosaccharomyces pombe and Characterization of the Recombinant Enzyme

cDNA Cloning of PhosphoethanolamineN-Methyltransferase from Spinach by Complementation inSchizosaccharomyces pombe and Characterization of the Recombinant Enzyme

Tsc13p Is Required for Fatty Acid Elongation and Localizes to a Novel Structure at the Nuclear-Vacuolar Interface in Saccharomyces cerevisiae

Isolation and Functional Characterization ofN-Methyltransferases That Catalyze Betaine Synthesis from Glycine in a Halotolerant Photosynthetic Organism Aphanothece halophytica

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