scholarly journals Effect of cis-unsaturated fatty acids on aortic protein kinase C activity

1989 ◽  
Vol 258 (1) ◽  
pp. 171-175 ◽  
Author(s):  
K R Dell ◽  
D L Severson
Keyword(s):  
Fatty Acids ◽  
Protein Kinase C ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Unsaturated Fatty Acids ◽  
Acid Activation ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Fatty Acid Activation

Long-chain cis-unsaturated fatty acids could substitute for phosphatidylserine and activate bovine aortic protein kinase C in assays with histone as substrate. The optimal concentration was 24-40 microM for oleic, linoleic and arachidonic acids. With arachidonic acid, the Ka for Ca2+ was 130 microM and kinase activity was maximal at 0.5 mM-Ca2+. Diolein only slightly activated the oleic acid-stimulated enzyme at low physiological Ca2+ concentrations (0.1 and 10 microM). Oleic acid also stimulated kinase C activity, determined with a Triton X-100 mixed-micellar assay. Under these conditions, the fatty acid activation was absolutely dependent on the presence of diolein, but a Ca2+ concentration of 0.5 mM was still required for maximum kinase C activity. The effect of fatty acids on protein kinase C activity was also investigated with the platelet protein P47 as a substrate, since the properties of kinase C can be influenced by the choice of substrate. In contrast with the results with histone, fatty acids did not stimulate the phosphorylation of P47 by the aortic protein kinase C. Activation of protein kinase C by fatty acids may allow the selective phosphorylation of substrates, but the physiological significance of fatty acid activation is questionable because of the requirement for high concentrations of Ca2+.

scholarly journals Phosphatidylcholine-dependent protein kinase C activation. Effects of cis-fatty acid and diacylglycerol on synergism, autophosphorylation and Ca2+-dependency

1992 ◽  
Vol 284 (1) ◽  
pp. 221-226 ◽  
Author(s):  
S G Chen ◽  
D Kulju ◽  
S Halt ◽  
K Murakami
Keyword(s):  
Protein Kinase C ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Acid Activation ◽  
Type Iii ◽  
Kinase C ◽  
Synergistic Activation ◽  
Protein Kinase C Activity ◽  
Fatty Acid Activation ◽  
Protein Kinase C Activation

A long-chain neutral phospholipid, dioleoylphosphatidylcholine, was found to support protein kinase C activation by cis-fatty acid and diacylglycerol (DAG). This effect of phosphatidylcholine (PC) is totally dependent on the presence of cis-fatty acid; PC greatly stimulates the cis-fatty acid-induced protein kinase C activity, but it does not activate protein kinase C at all, even in the presence of DAG, if cis-fatty acid is absent. DAG, however, plays a modulatory role in the presence of Ca2+; it further enhances the PC-potentiated cis-fatty acid activation of protein kinase C. Although the activities of all three protein kinase C subtypes tested (types I, II and III) are supported by this PC mechanism, type III is most sensitive to the DAG effect, and it is activated synergistically by cis-fatty acid and DAG. The potency of PC to support the synergistic activation of this subtype is equivalent to that of phosphatidylserine (PS). There are several differences, however, between PC- and PS-supported synergism observed in type III protein kinase C: (1) Ca(2+)-sensitivity is different; PC requires higher concentrations of Ca2+ (10-20 microM-Ca2+) than those required for PS (micromolar Ca2+); (2) PC/cis-fatty acid/DAG-induced autophosphorylation of protein kinase C subtypes (types I, II and III) is very weak, whereas PS/cis-fatty acid/DAG strongly stimulate autophosphorylation of these subtypes under the conditions at which both PC and PS systems fully activate the protein kinase C in terms of histone phosphorylation. These observations suggest that a neutral phospholipid such as PC may also participate in the activation and differential regulation of protein kinase C.

scholarly journals Cytoplasmic lipid bodies of neutrophils: formation induced by cis-unsaturated fatty acids and mediated by protein kinase C.

1991 ◽  
Vol 113 (1) ◽  
pp. 137-146 ◽  
Author(s):  
P F Weller ◽  
S W Ryeom ◽  
S T Picard ◽  
S J Ackerman ◽  
A M Dvorak
Keyword(s):  
Fatty Acids ◽  
Protein Kinase C ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Unsaturated Fatty Acids ◽  
Lipid Body ◽  
Lipid Bodies ◽  
Myristate Acetate ◽  
Body Formation ◽  
Kinase C

Lipid bodies, nonmembrane-bound cytoplasmic inclusions, serve as repositories of esterified arachidonate and are increased in cells associated with inflammatory reactions. We have evaluated stimuli and mechanisms responsible for lipid body formation within human polymorphonuclear leukocytes (PMNs). Arachidonic acid and oleic acid stimulated dose-dependent formation of lipid bodies over 0.5-1 h. Other C20 and C18 fatty acids were less active and demonstrated rank orders as follows: cis-unsaturated fatty acids were much more active than trans-fatty acids, and activity diminished with decreasing numbers of double bonds. Lipid bodies elicited in vitro with cis-fatty acids were ultrastructurally identical to lipid bodies present in PMNs in vivo. Lipid body induction was not because of fatty acid-elicited oxidants or fatty acid-induced ATP depletion. Cis-fatty acid-induced activation of protein kinase C (PKC) was involved in lipid body formation as evidenced by the capacity of other PKC activators, 1-oleoyl-2-acetyl-glycerol and two active phorbol esters, phorbol myristate acetate, and phorbol 12,13 dibutyrate, but not an inactive phorbol, to induce lipid body formation. The PKC inhibitor, 1-O-hexadecyl-2-O-methyl-glycerol, inhibited PMN lipid body formation induced by oleic and arachidonic acids and by 1-oleoyl-2-acetyl-glycerol and phorbol myristate acetate. Other PKC inhibitors (staurosporine, H-7) also inhibited lipid body formation. Formation of lipid bodies in PMNs is a specific cellular response, stimulated by cis-fatty acids and diglycerides and apparently mediated by PKC, which results in the mobilization and deposition of lipids within discrete, ultrastructurally defined cytoplasmic domains.

scholarly journals Regulation of epidermal-growth-factor-receptor signal transduction by cis-unsaturated fatty acids. Evidence for a protein kinase C-independent mechanism

1991 ◽  
Vol 278 (3) ◽  
pp. 679-687 ◽  
Author(s):  
X Casabiell ◽  
A Pandiella ◽  
F F Casanueva
Keyword(s):  
Signal Transduction ◽  
Fatty Acids ◽  
Protein Kinase C ◽  
Oleic Acid ◽  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Cell Lines ◽  
Kinase C ◽  
Epidermal Growth

The effect of acute treatment with non-esterified fatty acids (NEFA) on transmembrane signalling has been investigated in three different cell lines. In EGFR T17 cells, pretreatment with cis-unsaturated (oleic and palmitoleic acids) NEFA, but not with saturated or trans-unsaturated NEFA, inhibited the epidermal-growth-factor (EGF)-induced increases in cytosolic [Ca2+], membrane potential and Ins(1,4,5)P3 generation. The blocking effect was found to be time- and dose-dependent and rapidly reversible after washout. However, oleic acid treatment did not block either binding of 125I-EGF to its receptor or EGF-induced autophosphorylation of the EGF receptor. The mechanism of action of NEFA could not be attributed to protein kinase C activation, since (i) down-regulation of the enzyme by long-term treatment with phorbol esters did not prevent blockade by oleic acid, and (ii) the effects of acutely administered phorbol ester and oleic acid were additive. In this cell line, signalling at bradykinin and bombesin receptors was also impaired by oleic acid. In A431 cells, oleic acid also blocked signal transduction at the EGF and B2 bradykinin receptors. Finally, in PC12 cells, oleic acid blocked the Ca2+ influx mediated by the activation of B2 bradykinin receptors. In conclusion: (1) NEFA block signal transduction by interfering with receptor-phospholipase C or phospholipase C-substrate interaction without preventing ligand binding; (2) NEFA do not act by a protein kinase C-mediated mechanism; (3) the effect of NEFA is dependent on their configuration rather than hydrophobicity or chain length; (4) this effect is evident in several different cell lines and receptor systems.

scholarly journals Inhibitory effects of omega-3 fatty acids on protein kinase C activity in vitro

2001 ◽  
Vol 6 (2) ◽  
pp. 246-248 ◽  
Author(s):  
H F Seung Kim ◽  
E J Weeber ◽  
J D Sweatt ◽  
A L Stoll ◽  
L B Marangell
Keyword(s):  
Fatty Acids ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Omega 3 Fatty Acids ◽  
Omega 3 ◽  
Inhibitory Effects ◽  
Kinase C ◽  
Protein Kinase C Activity
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