Methylation of nonpolar lipids: Identification and characterization

Zatz, Martin; Engelsen, S.; Kloog, Yoel; Dudley, Peter A.; Markey, Sanford P.

doi:10.1007/978-1-349-06343-7_71

Cited by 5 publications

(9 citation statements)

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“…The major proportion (50-70%) of the chloroform-soluble 3H label was not incorporated in methylated phospholipid (Moore et al, 1982); the 3H-labelled material eluted in 2-5 ml in Fig. 2(a) is mainly neutral lipid (Zatz et al, 1981;Bougnoux et al, 1983). We could detect no increase in the level of any of the methylated phospholipids within 10 min of antigen addition (Fig.…”

Section: Resultsmentioning

confidence: 99%

Calcium signals and phospholipid methylation in eukaryotic cells

Moore¹,

Johannsson²,

Hesketh³

et al. 1984

Biochemical Journal

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Rat basophil leukaemic (2H3) cells, mast cells and mouse thymocytes respond to stimulation by specific ligands with an increase in the free cytosolic Ca2+ concentration. The time courses of these Ca signals and the biological responses have been compared with changes in phospholipid metabolism. Increased phosphoinositide metabolism coincides with the Ca signals and the responses in each cell system, whereas any increase in phospholipid methylation during the response is less than one molecule per receptor and at least 5-50-fold less than the increases reported previously. Furthermore, no significant changes were detected in the concentration of S-adenosylmethionine, the methyl-group donor in the synthesis of methylated phospholipids. The hypothesis that phospholipid methylation is obligatory for receptor-mediated Ca signals is not supported by these data and requires critical re-evaluation.

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Section: Resultsmentioning

confidence: 99%

Calcium signals and phospholipid methylation in eukaryotic cells

Moore¹,

Johannsson²,

Hesketh³

et al. 1984

Biochemical Journal

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“…Non-polar lipid methylation was usually assayed in conjunction with phospholipid methylation as described above. Whenever non-polar methylation alone was assessed it was assayed according to the method of Zatz et al (1981) after heptane extraction of the basolateral membranes.…”

Section: Enzymic Assaysmentioning

confidence: 99%

“…Similar reactions in cultured toad bladder cells (Wisemann et al, 1985) and apical membranes prepared from the cultured amphibian cell line A6 (Sariban-Sohraby et al, 1984) have also been shown to influence electrogenic sodium transport. S-Adenosyl-L-methionine is the methyl donor for most known biological transmethylation reactions (Zatz et al, 1981;Kloog et al, 1982;Pelech & Vance, 1984), including those involved in the methylation of phospholipids, non-polar lipids and protein. Recently, Hattori & Kanfer (1984) have shown that S-adenosyl-Lmethionine inhibited Na++K+-ATPase activity in rat brain microsomes.…”

Section: Introductionmentioning

confidence: 99%

S-adenosyl-l-methionine modulates Na+ + K+-ATPase activity in rat colonic basolateral membranes

Brown

Dudeja

Brasitus

1988

Biochemical Journal

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Rat colonic basolateral membranes were incubated with S-adenosyl-L-[methyl-3H]methionine (0.3 mM) at 37 degrees C for 2 h at pH 9.0. This resulted in an increase in the specific activity of Na+ + K+-ATPase by 60%. Kinetic parameter analysis revealed a 2-fold increase in the Vmax. of this enzymatic activity, whereas the Km for ATP was unchanged. The methylation inhibitor S-adenosyl-L-homocysteine (2 mM) significantly reduced these S-adenosyl-L-methionine-stimulated increases in specific activity and the Vmax. of Na+ + K+-ATPase. S-Adenosyl-L-methionine treatment of basolateral membranes was also found to significantly increase the fluidity of these preparations, as assessed by steady-state fluorescence polarization techniques using the fluorophore 1,6-diphenyl-1,3,5-hexatriene; S-adenosyl-L-homocysteine (2 mM) again markedly reduced this S-adenosyl-L-methionine-induced increase in fluidity. While transmethylation reactions involving phospholipids, non-polar lipids and proteins were all found to exist in rat colonic basolateral membranes, based on a number of observations, the results of the present studies suggest that transmethylation of membrane phospholipids, but not membrane non-polar lipids or proteins, influenced the fluidity of basolateral membranes which, in turn, modified Na+ + K+-ATPase activity in these membranes.

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“…Another source of error in the determination of the kinetics of phospholipid Nmethyltransferase is the possible methylation of lipids other than phospholipids. Several neutral lipids are formed by incubation with AdoMet (Zatz et al, 1981;Alemany et al, 1982a) or by incubation of intact cells with methionine (Rabe & McGee, 1982). Some of these lipids have been identified as methyl esters of fatty acids (Zatz et al, 1981) and as S-methyl-N-oleoyl-mercaptoethylamide (Zatz et al, 1982).…”

Section: Enzymes Involved In Phosphatidylcholine Synthesismentioning

confidence: 99%