Phospholipid polar head group manipulation modulates concanavalin A agglutinability of LM fibroblasts

Schroeder, Friedhelm

doi:10.1021/bi00269a026

Cited by 16 publications

(4 citation statements)

References 43 publications

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“…Consistent with the latter postulate are the observations indicating that methylation of membrane phospholipids plays a role in both signal transduction (12,13) and receptor modulation (14). In fibroblasts, the manipulation of the membrane composition of methylated phospholipids altered the binding properties of Con A (15). Furthermore, increasing the ratio of highly methylated to total phospholipids lowered the affinity of Con A for its receptor and increased the number of sites per cell.…”

Section: Resultssupporting

confidence: 58%

Phospholipid methylation in starfish spermatozoa is linked to sperm chemoattraction.

Tezón¹,

Miller²,

Bardin³

1986

Proc. Natl. Acad. Sci. U.S.A.

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The mechanism whereby ovarian peptides cause sperm attraction was studied in the starfish. Phospholipid methylation and protein-O-carboxyl methylation, reactions linked to chemotactic responses in a variety of systems, were studied in starfish sperm. When sperm were preincubated with [methyl-3H]methionine and then exposed to the attractant, a rapid drop in radioactivity occurred in the phospholipid fraction. Methylated phospholipids decreased by 90% in the first 2 sec; however, no change was observed in endogenous methylation of protein carboxyl groups. The effect on phospholipid methylation was dose dependent, with a 40% reduction in radioactive phospholipids in sperm occurring with the minimal amount of attractant necessary to obtain a positive response in a sperm attraction bioassay. Attractants from species of starfish with little or no cross-reactivity in the bioassay had a limited effect on phospholipid methylation. The transmethylase inhibitor, homocysteine, caused a marked decrease in the accumulation of methylated phospholipids under basal conditions, which was correlated with as much as a 50-fold increase in sperm sensitivity to the attractant. The addition of chemoattractant resulted in a reduction in the amount of all individual methylated phospholipids, but the amount of phosphatidylmono[3H]methylethanolamine relative to the other methylated phospholipid decreased by a factor of 4 after stimulation. Homocysteine had the same effect. The reduction in methylated phospholipids by attractants suggests that phospholipid methylation is linked to the mechanism of action of these peptides. Methylation of phospholipids may play a role in the rapid desensitization of sperm cells to the attractant, which would be required for the orientation of the spermatozoa in the gradient of ovarian peptide.Sperm chemotaxis has been demonstrated in Asteroidea, a major class ofechinoderms (1). The substance responsible for the attraction is produced by the ovaries and is of low molecular weight, highly polar, sensitive to proteases, and stable to heat and acid (T. Punnett and R.L.M., unpublished data). The affected spermatozoa swim up a gradient of the chemoattractant, which is specific at least at the family level in starfish. This response leads to more efficient and appropriate sperm-egg interaction in the open sea, where fertilization normally takes place in these animals. However, the mechanism by which these attractants exert their effect on sperm is not known.Transmethylase reactions are involved in a variety of chemotactic responses (for review, see ref.2). In bacteria, membrane-associated proteins are methylated by a proteincarboxyl methyltransferase as a requirement for chemotaxis (3,4). Many cells such as cellular slime molds (5), guinea pig macrophages (6), and rabbit neutrophils (2) exhibit changes in the phospholipid composition of the plasma membrane consistent with the activation of phospholipid methyltransferases after exposure to specific attractants. Because of the well-known involvement of transm...

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Section: Resultssupporting

confidence: 58%

Phospholipid methylation in starfish spermatozoa is linked to sperm chemoattraction.

Tezón¹,

Miller²,

Bardin³

1986

Proc. Natl. Acad. Sci. U.S.A.

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“…It is well established that experimental changes in fluidity of the whole LM cell plasma membrane result in many functional changes including endocytosis (Schroeder, 1981b;Schroeder & Kier, 1983), lectin binding and agglutination (Schroeder, 1982), transport (F. Schroeder, unpublished observation), and adenylate cyclase activity (Engelhard! et al, 1976).…”

Section: Discussionmentioning

confidence: 99%

Charged anesthetics selectively alter plasma membrane order

Sweet¹,

Wood²,

Schroeder³

1987

Biochemistry

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Although indirect evidence supporting differential lipid fluidity in the two monolayers of plasma membranes has accumulated, unambiguous demonstration of this difference has been difficult to obtain. In the present study, the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH), selective quenching of fluorescence by trinitrophenyl groups, and differential polarized phase fluorescence techniques were used to directly examine the static (order) and dynamic (rotational rate) components of lipid motion in the exofacial and cytofacial leaflets of LM fibroblast plasma membranes. The limiting anisotropy (0.137), the order parameter (0.590), and the rotational relaxation time (1.20 ns) of DPH in the plasma membranes (inner plus outer leaflet) indicated rapid but restricted probe motion in the lipid environment. However, the statics and dynamics of DPH motion in the individual monolayers were significantly (p less than 0.025) different. The limiting anisotropy, order parameter, and rotational relaxation time of DPH in the cytofacial monolayer were 0.036, 0.08, and 0.16 ns, respectively, greater than calculated for the exofacial monolayer of the LM plasma membrane. At appropriate concentrations, phenobarbital and, to a lesser degree, pentobarbital preferentially reduced the limiting anisotropy of DPH calculated for the exofacial leaflet while prilocaine reduced the limiting anisotropy of DPH in the cytofacial leaflet of LM fibroblast plasma membranes. In contrast, the putative cytofacial anesthetic procaine failed to show any preference for either leaflet. Arrhenius plots of DPH fluorescence in LM plasma membranes showed a prominent characteristic break point near 30-32 degrees C. Phenobarbital, pentobarbital, and procaine did not affect this break point while prilocaine selectively abolished it. The break point was therefore assigned to the inner monolayer of the LM plasma membrane.

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“…This approach has been used for modification of the phospholipid composition in yeast (Ratcliffe et al, 1973), protozoa (Smith, 1983), Friend cells (Kaiho and Mizuno, 1984), rat hepdtocytes (Akesson, 19771, neuroblastoma cells (Yavin, 1977j, M, cells (Honma et al, 1982, LM cells (Gilmore et al, 1979;Schroeder, 19821, and monolayer nerve cell cultures (Robert et al, 1978;Yavin, 1985). Changes o f t h e polar moiety of phospholipids can affect the phase transition temperature (Boyle and Dean, 1982) and fluidity of cell membranes (Gilmore et al, 1979;Hirata and Axelrod, 1980;Schroeder, 1982).…”

Section: Modifications Of Membrane Lipid Compositionmentioning

confidence: 99%

Effect of Modification of Membrane Phospholipid Composition on Phospholipid Methylation in Aggregating Cell Culture

Dainous¹,

Kanfer²

1986

Enzymes of Lipid Metabolism II

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Phospholipid polar head group manipulation modulates concanavalin A agglutinability of LM fibroblasts

Abstract: The effect of phospholipid polar head group manipulation in LM fibroblasts on fluoresceinylconcanavalin A binding, concanavalin A mediated hemadsorption, and concanavalin A mediated agglutination was determined. Choline

Cited by 16 publications

References 43 publications

Phospholipid methylation in starfish spermatozoa is linked to sperm chemoattraction.

Phospholipid methylation in starfish spermatozoa is linked to sperm chemoattraction.

Charged anesthetics selectively alter plasma membrane order

Effect of Modification of Membrane Phospholipid Composition on Phospholipid Methylation in Aggregating Cell Culture

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