scholarly journals Synergistic activation of type III protein kinase C by cis-fatty acid and diacylglycerol

1992 ◽  
Vol 282 (1) ◽  
pp. 33-39 ◽  
Author(s):  
S G Chen ◽  
K Murakami
Keyword(s):  
Protein Kinase C ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Second Messengers ◽  
Type I ◽  
Physiological Concentration ◽  
Type Iii ◽  
Kinase C ◽  
Synergistic Activation ◽  
Protein Kinase C Activation

Micromolar concentrations of cis-fatty acid synergistically activate type III protein kinase C with diacylglycerol. This synergistic effect occurs at low concentrations of cis-fatty acid and diacylglycerol, and it is capable of inducing almost full activation of this protein kinase C subtype at a physiologically relevant Ca2+ concentration (2 microM). The synergistic activation mode can be observed even in the absence of Ca2+, but micromolar Ca2+ significantly enhances the type III protein kinase C activation. cis-Fatty acid also augments the diacylglycerol-induced activation of other subtypes (type I and II), although the effect is smaller than that observed in type III. Neither the diacylglycerol- nor the cis-fatty acid-dependent mode of activation can fully activate any of these subtypes at a physiological concentration of Ca2+ (2 microM). Our results suggest that the generation of three second messengers, i.e. the increase in intracellular Ca2+ concentration and the generation of both cis-fatty acid and diacylglycerol in the cell, may be necessary signals for protein kinase C activation, particularly for type III protein kinase C.

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 Differential localization of protein kinase C isozymes in retinal neurons.

1991 ◽  
Vol 112 (6) ◽  
pp. 1241-1247 ◽  
Author(s):  
N Usuda ◽  
Y Kong ◽  
M Hagiwara ◽  
C Uchida ◽  
M Terasawa ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Bipolar Cells ◽  
Type I ◽  
Rabbit Retina ◽  
Type Ii ◽  
Retinal Neurons ◽  
Type Iii ◽  
Kinase C ◽  
Rod Bipolar Cells

We report the immunohistochemical localization of protein kinase C isozymes (types I, II, and III) in the rabbit retina using the monospecific monoclonal antibodies MC-1a, MC-2a, and MC-3a. Using immunoblot analysis of partially purified protein kinase C preparations of rabbit retina, types II and III isozymes alone were detected. The activity of type III was the stronger. By light microscopic immunohistochemical analysis, retinal neurons were negative for type I and positive for type II and type III isozymes. Type II was more diffusely distributed through the retinal layers, but was distinctive in ganglion cells, bipolar cells, and outer segments. The immunoreactivity was stronger for type III isozyme, and it was observed in mop (rod) bipolar cells and amacrine cells. By using immunoelectron microscopy, the cytoplasm of the cell body, the axon, and dendrites of the mop bipolar cells were strongly immunoreactive for type III. The so-called rod bipolar cells were for the first time seen to form synapses with rod photoreceptor cells. These differential localizations of respective isozymes in retinal neurons suggest that each isozyme has a different site of function in each neuron.

scholarly journals Purification of PKC-I, an endogenous protein kinase C inhibitor, and types II and III protein kinase C isoenzymes from human neutrophils

1992 ◽  
Vol 284 (2) ◽  
pp. 399-405 ◽  
Author(s):  
K J Balazovich ◽  
E L McEwen ◽  
M L Lutzke ◽  
L A Boxer ◽  
T White
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Human Neutrophils ◽  
Type I ◽  
Dependent Manner ◽  
Type Ii ◽  
Western Blots ◽  
Type Iii ◽  
Kinase C ◽  
Endogenous Protein

Human neutrophil protein kinase C (PKC) activity is inhibited by an endogenous protein found primarily in the pellet fraction from homogenized specific granules, which was both heat- and proteinase-sensitive [Balazovich, Smolen & Boxer (1986) J. Immunol. 137, 1665-1673]. We now report that two PKC isoenzymes and the endogenous PKC inhibitor, which we named PKC-I, were purified from human neutrophils. A neutrophil soluble fraction that was subjected to DEAE-Sephacel chromatography yielded highly enriched PKC because, by definition, enzymic activity was strictly dependent on Ca2+ and phosphatidylserine. Hydroxyapatite chromatography resolved two peaks of PKC activity. Type II and Type III PKC isoenzymes were each identified on Western blots by using isoenzyme-specific monoclonal antibodies. Unlike rat brain, from which PKC isoenzymes were also purified, Type I PKC was not detected in human neutrophils. Western blots indicated that both Type II and Type III PKC isoenzymes had molecular masses near 80 kDa. In agreement with other reports, PKC was autophosphorylated in vitro. PKC-I, an endogenous neutrophil inhibitor of PKC, was purified to apparent homogeneity by DEAE-Sephacel and S-400 Sephacel chromatography. PKC-I had a molecular mass of 41 kDa. PKC-I inhibited purified PKC activity stimulated by 1,2-diacylglycerols in a concentration-dependent manner, and inhibited PKC-dependent phosphorylation of proteins present in neutrophil cytosol.

Free fatty acids and protein kinase C activation induce GPR120 (free fatty acid receptor 4) phosphorylation

2014 ◽  
Vol 723 ◽  
pp. 368-374 ◽  
Author(s):  
Omar B. Sánchez-Reyes ◽  
M. Teresa Romero-Ávila ◽  
Jean A. Castillo-Badillo ◽  
Yoshinori Takei ◽  
Akira Hirasawa ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Protein Kinase C ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Protein Kinase ◽  
Free Fatty Acids ◽  
Acid Receptor ◽  
Kinase C ◽  
Free Fatty Acid Receptor ◽  
Protein Kinase C Activation
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