Calmodulin modulates phospholipid methylation in

Gil, Merche García; Alemany, Susana; Cao, Dolores Marín; Castaño, José G.; Mato, JoséM.

doi:10.1016/0006-291x(80)90564-1

Cited by 25 publications

(6 citation statements)

References 7 publications

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“…Glucagon administered in vivo has been shown to increase the phosphorylation of PLMT [10], and this effect was mimicked in vitro by cyclic AMP-dependent protein kinase [11]. PLMT is also activated by a Ca2+-dependent mechanism [3,[12][13][14][15]. In hepatocytes, the activation of PLMT by angiotensin is associated with phosphorylation of PLMT [16] on a residue different from that phosphorylated by cyclic AMP-dependent protein kinase, and in adipocytes the stimulatory effect of oxytocin on PLMT is additive with that caused by isoprenaline [12].…”

Section: Introductionmentioning

confidence: 99%

Stimulation of adipocyte phospholipid methyltransferase activity by phorbol 12-myristate 13-acetate. Differential regulation of phospholipid methyltransferase and lipolysis

Kelly¹

1987

Biochemical Journal

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The present studies demonstrate that treatment of rat adipocytes with the phorbol ester phorbol 12-myristate 13-acetate (PMA) causes a dose-dependent stimulation of phospholipid methyltransferase (PLMT) activity. The stimulatory effect of PMA was not additive with that of isoprenaline or forskolin. The sensitivity of stimulated PLMT activity to inhibition by insulin, however, was decreased in the presence of PMA. The inhibitory effect of a maximal concentration of insulin on PLMT was unchanged in the presence of PMA. In contrast with the effects on PLMT, the lipolytic response of adipocytes to isoprenaline and the anti-lipolytic response to insulin were unaffected by PMA. These data suggest that PLMT is, whereas hormone-sensitive lipase is not, an intracellular target for the action of PMA. The lack of effect of PMA on lipolysis suggests that PLMT and hormone-sensitive lipase can be regulated by separate mechanisms. Furthermore, phorbol esters do not interfere in the regulatory pathway whereby insulin inhibits PMLT or lipolysis.

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Section: Introductionmentioning

confidence: 99%

Stimulation of adipocyte phospholipid methyltransferase activity by phorbol 12-myristate 13-acetate. Differential regulation of phospholipid methyltransferase and lipolysis

Kelly¹

1987

Biochemical Journal

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“…No evidence supporting this hypothesis was however given. Furthermore, the addition of exogenous phosphatidylethanolamine (2mg/ml) does not change the enzyme activity of homogenates from either control or glucagon-treated hepatocytes (Castafio et al, 1980); similarly, phosphatidylethanolamine added to rat liver microsomes does not stimulate methylation (Schneider & Vance, 1979); and the N-methylation of phosphatidylethanolamine to phosphatidylcholine in rat hepatocytes remains constant when the rate of phosphatidylethanolamine synthesis is varied up to 8-fold (Sundler & Akesson, 1975). These results indicate that, as reported by Bremer (1969), in hepatocytes isolated from normally fed rats the concentration of phosphatidylethanolamine is enough to saturate the methylation reaction.…”

Section: Cpt-campmentioning

confidence: 93%

What is the function of phospholipid N-methylation?

Mato¹,

Alemany²

1983

Biochemical Journal

117

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“…PtdCho and lyso-PtdCho were quantified after separation by t.l.c. on silica gel-60 plates (Garcia Gil et al, 1980). [1-3H]Ethanolamine and [3-3Hlserine were added at concentrations of respectively 2,Ci/ml and 20,uCi/ml.…”

mentioning

confidence: 99%

“…PtdEtn, PtdCho and PtdSer were quantified after separation by t.l.c. on silica gel-60 plates as described by Garcia Gil et al (1980).…”

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confidence: 99%

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Phospholipid turnover during phagocytosis in human polymorphonuclear leucocytes

Gil

Alonso

Chiva

et al. 1982

Biochemical Journal

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We have previously observed that the phagocytosis of zymosan particles coated with complement by human polymorphonuclear leucocytes is accompanied by a time-and dose-dependent inhibition of phosphatidylcholine synthesis by transmethylation [Garcia Gil, Alonso, Sanchez Crespo & Mato (1981) Biochem. Biophys. Res. Commun. 101, 740-7481. The present studies show that phosphatidylcholine synthesis by a cholinephosphotransferase reaction is enhanced, up to 3-fold, during phagocytosis by polymorphonuclear cells. This effect was tested by both measuring the incorporation of radioactivity into phosphatidylcholine in cells labelled with choline, and by assaying the activity of CDP-choline:diacylglycerol cholinephosphotransferase. The time course of CDP-choline:diacylglycerol cholinephosphotransferase activation by zymosan mirrors the inhibition of phospholipid methyltransferase activity previously reported. The extent of incorporation of radioactivity into phosphatidylcholine induced by various doses of zymosan correlates with the physiological response of the cells to this stimulus. This effect was specific for phosphatidylcholine, and phosphatidylethanolamine turnover was not affected by zymosan. The purpose of this enhanced phosphatidylcholine synthesis is not to provide phospholipid molecules rich in arachidonic acid. The present studies show that about 80% of the arachidonic acid generated in response to zymosan derives from phosphatidylinositol. A transient accumulation of arachidonoyldiacylglycerol has also been observed, which indicates that a phospholipase C is responsible, at least in part, for the generation of arachidonic acid. Finally, isobutylmethylxanthine and quinacrine, inhibitors of phosphatidylinositol turnover, inhibit both arachidonic acid generation and phagocytosis, indicating a function for this pathway during this process.PtdCho can be synthesized either by a cholinephosphotransferase reaction or by transmethylation. The first pathway involves the transfer of a phosphocholine group from CDP-choline to a 1,2-diacylglycerol molecule (Kennedy & Weiss, 1956). The second pathway involves the addition of three methyl groups into the amino group of a PtdEtn molecule, with S-adenosylmethionine as the methyl donor (Bremer & Greenberg, 1961). The purpose of these two pathways for PtdCho synthesis remains unclear. In rat hepatocytes cyclic AMP

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Calmodulin modulates phospholipid methylation in

Cited by 25 publications

References 7 publications

Stimulation of adipocyte phospholipid methyltransferase activity by phorbol 12-myristate 13-acetate. Differential regulation of phospholipid methyltransferase and lipolysis

Stimulation of adipocyte phospholipid methyltransferase activity by phorbol 12-myristate 13-acetate. Differential regulation of phospholipid methyltransferase and lipolysis

What is the function of phospholipid N-methylation?

Phospholipid turnover during phagocytosis in human polymorphonuclear leucocytes

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