Molecular, cellular, and physiological responses to phosphatidic acid formation in plants

The acylation of 1-acyl-sn-glycero-3-phosphate to form phosphatidic acid was studied using a neuronal nuclear fraction N1 and microsomal fractions P3, R (rough), S (smooth), and P (neuronal microsomes from nerve cell bodies) isolated from cerebral cortices of 15-day-old rabbits. The assays contained this lysophospholipid, ATP, CoA, MgCl2, NaF, dithiothreitol, and radioactive palmitate, oleate, or arachidonate. Of the subfractions, N1 and R had the highest specific activities (expressed per micromole phospholipid in the fraction). The rates with oleate were two to four times the values seen for phosphatidic acid formation from sn-[3H]glycero-3-phosphate and oleoyl-CoA. Using oleate or palmitate, fraction R had superior specific rates to N1 at low lysophosphatidic acid concentrations. With increasing lysophospholipid concentrations the specific rates of N1 and R came closer together and maintained at least a twofold superiority over fraction P. Fraction S had the lowest specific rates of phosphatidic acid formation. Fractions N1, R, and P showed a preference for palmitate and oleate over arachidonate, particularly at low concentrations of lysophosphatidic acid. For N1 and R, the preference was also more marked at higher concentrations of fatty acid. Thus a selectivity for saturated and monounsaturated fatty acids was shown in the formation of phosphatidic acid, as was a concentration of acylating activity in the neuronal nucleus and the rough endoplasmic reticulum.Key words: 1-acyl-sn-glycero-3-phosphate, acylation, neuronal nuclei, microsomes, cerebral cortex.

Download Full-text

Fatty Acid Binding Protein: Stimulation of Microsomal Phosphatidic Acid Formation

Archives of Biochemistry and Biophysics ◽

10.1006/abbi.1997.9957 ◽

1997 ◽

Vol 341 (1) ◽

pp. 112-121 ◽

Cited By ~ 81

Author(s):

Christopher A. Jolly ◽

Timothy Hubbell ◽

William D. Behnke ◽

Friedhelm Schroeder

Keyword(s):

Fatty Acid ◽

Phosphatidic Acid ◽

Fatty Acid Binding Protein ◽

Binding Protein ◽

Acid Formation ◽

Fatty Acid Binding ◽

Acid Binding Protein ◽

Stimulation Of

Download Full-text

Phospholipase D1 regulates high-affinity IgE receptor-induced mast cell degranulation

Blood ◽

10.1182/blood-2004-06-2091 ◽

2004 ◽

Vol 104 (13) ◽

pp. 4122-4128 ◽

Cited By ~ 21

Author(s):

Tomohiro Hitomi ◽

Juan Zhang ◽

Liliana M. Nicoletti ◽

Ana Cristina G. Grodzki ◽

Maria C. Jamur ◽

...

Keyword(s):

Mast Cell ◽

Phosphatidic Acid ◽

Mast Cell Degranulation ◽

Dominant Negative ◽

Acid Formation ◽

Wild Type ◽

High Affinity ◽

Phospholipase D1 ◽

High Affinity Ige Receptor

Abstract To investigate the role of phospholipase D (PLD) in FcϵRI signaling, the wild-type or the catalytically inactive forms of PLD1 or PLD2 were stably overexpressed in RBL-2H3 mast cells. FcϵRI stimulation resulted in the activation of both PLD1 and PLD2. However, PLD1 was the source of most of the receptor-induced PLD activity. There was enhanced FcϵRI-induced degranulation only in cells that overexpressed the catalytically inactive PLD1. This dominant-negative PLD1 enhanced FcϵRI-induced tyrosine phosphorylations of early signaling molecules such as the receptor subunits, Syk and phospholipase C-γ which resulted in faster release of Ca2+ from intracellular sources. Therefore, PLD1 negatively regulates signals upstream of the Ca2+ response. However, FcϵRI-induced PLD activation required Syk and was downstream of the Ca2+response, suggesting that basal PLD1 activity rather than that activated by cell stimulation controlled these early signaling events. Dominant-negative PLD1 reduced the basal phosphatidic acid formation in unstimulated cells, which was accompanied by an increase in FcϵRI within the lipid rafts. These results indicate that constitutive basal PLD1 activity by regulating phosphatidic acid formation controls the early signals initiated by FcϵRI aggregation that lead to mast cell degranulation. (Blood. 2004;104:4122-4128)

Download Full-text

Verapamil inhibits phosphatidic acid formation and modifies phosphoinositide metabolism in stimulated platelets

European Journal of Pharmacology ◽

10.1016/0014-2999(90)90042-5 ◽

1990 ◽

Vol 182 (3) ◽

pp. 457-464 ◽

Cited By ~ 3

Author(s):

Sheryl T. Homa ◽

Shah Nawaz Khan ◽

Dolores M. Conroy ◽

Andrew E. Speak ◽

Anthony D. Smith

Keyword(s):

Phosphatidic Acid ◽

Acid Formation ◽

Phosphoinositide Metabolism

Download Full-text

THE INCORPORATION OF α-GLYCEROPHOSPHATE-32P INTO THE LIPIDS OF RAT BRAIN PREPARATIONS: II. ON THE BIOSYNTHESIS OF MONOPHOSPHOINOSITIDE

Canadian Journal of Biochemistry ◽

10.1139/o67-007 ◽

1967 ◽

Vol 45 (1) ◽

pp. 63-70 ◽

Cited By ~ 10

Author(s):

F. Possmayer ◽

K. P. Strickland

Keyword(s):

Phosphatidic Acid ◽

Rat Brain ◽

Isotope Dilution ◽

Time Course ◽

Acid Formation ◽

Dilution Experiments ◽

Phosphatide Acid

Previous investigations conducted in this laboratory showed a number of differences in the cytosine nucleotide requirement for the incorporation of α-glycerophosphate (α-G32P) into the monophosphoinositide of rat brain preparations compared to the pathway described by Paulus and Kennedy, where α-glycerophosphate → phosphatide acid → CDP-diglyceride → monophosphoinositide, and CTP is specifically required. Experiments were carried out with rat brain preparations to determine the nature of the mechanism whereby CDP-choline is as effective as or more effective than CTP in stimulating the incorporation of α-G32P into monophosphoinositide. Isotope dilution experiments in which unlabeled phosphatidic acid and CDP-diglyceride were used, yielded results consistent with the view that both of these compounds are intermediates in the incorporation of a-G32P into monophosphoinositide stimulated by either CTP or CDP-choline. Time-course experiments where cytosine nucleotides were added either at the beginning or after 20 minutes produced a pattern of labeling which could be fitted into the above interpretation, provided that newly formed radioactive molecules of phosphatide acid could be used selectively and CTP in some way inhibits phosphatide acid formation or accumulation. The latter could account for the observation that monophosphoinositide becomes far more actively labeled than phosphatidic acid in the presence of added CTP.

Download Full-text

Thrombin-induced platelet responses differ in requirement for receptor occupancy. Evidence for tight coupling of occupancy and compartmentalized phosphatidic acid formation.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)68772-7 ◽

1981 ◽

Vol 256 (18) ◽

pp. 9393-9396

Author(s):

H. Holmsen ◽

C.A. Dangelmaier ◽

H.K. Holmsen

Keyword(s):

Phosphatidic Acid ◽

Receptor Occupancy ◽

Acid Formation ◽

Tight Coupling

Download Full-text

Action of guanosine 5′-[β-thio]diphosphate on thrombin-induced activation and Ca2+ mobilization in saponin-permeabilized and intact human platelets

Biochemical Journal ◽

10.1042/bj2550885 ◽

1988 ◽

Vol 255 (3) ◽

pp. 885-893 ◽

Cited By ~ 14

Author(s):

K S Authi ◽

G H R Rao ◽

B J Evenden ◽

N Crawford

Keyword(s):

Phosphatidic Acid ◽

Phospholipase C ◽

G Protein ◽

Protein Function ◽

Low Dose ◽

Shape Change ◽

Acid Formation ◽

Functional Responses ◽

Permeabilized Cells ◽

Fura 2

The non-hydrolysable guanine analogues guanosine 5′-[gamma-thio]triphosphate (GTP[S]) and guanosine 5′-[beta-thio]diphosphate (GDP[S]) have been used extensively (as promoters and inhibitors respectively) to probe the importance of G-protein function. We report on the use of GDP[S] in permeabilized and intact platelets. The stimulatory analogue GTP[S] (9-60 microM) induces shape change, aggregation and 5-hydroxy[14C]-tryptamine secretion when added to saponin (12-14 micrograms/ml)-permeabilized platelets, but not to intact platelets. In line with the activation responses in permeabilized cells, GTP[S] induces an increase in [32P]-phosphatidic acid, which is indicative of phospholipase C activity. GDP[S] (greater than 400 microM) totally inhibits GTP[S] (90 microM)-stimulated phospholipase C activity and functional responses in saponized platelets. GDP[S] (1 mM) was also effective at inhibiting low-dose thrombin (0.1 unit/ml)-induced aggregation and secretion responses (without affecting shape change) in permeabilized platelets with inhibition of [32P]-phosphatidic acid formation. At higher doses of thrombin (greater than 0.5 unit/ml), both functional responses and [32P]phosphatidic acid formation are restored in the presence of GDP[S]. Studies on intact cells revealed that GDP[S] was as effective at inhibiting low-dose thrombin-induced functional responses as in the permeabilized cells, but there was no inhibition of [32P]phosphatidic acid formation, indicating that the agent is nonmembrane-penetrating. This reflected the fact that GDP[S] has additional inhibitory sites on the surface of platelets. In Fura-2-loaded cells GDP[S] inhibited thrombin-induced Ca2+ mobilization, as measured by Fura-2 fluorescence, in a dose-dependent manner. In studies with and without Ca2+ present on the outside, the effect of GDP[S] was to block Ca2+ influx. These studies indicate that, although GDP[S] is a valuable tool in studying G-protein function in permeabilized cells, it also has inhibitory activities on the surface of platelets, and one of these has been identified as an effect on the Ca2+-influx channel after agonist stimulation.

Download Full-text