scholarly journals Exogenous sphingosine 1-phosphate and sphingosylphosphorylcholine do not stimulate phospholipase D in C6 glioma cells.

1999 ◽  
Vol 46 (1) ◽  
pp. 99-106 ◽  
Author(s):  
A Dygas ◽  
M Sidorko ◽  
M Bobeszko ◽  
J Barańska
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase D ◽  
C6 Glioma Cells ◽  
C6 Cells ◽  
Glioma C6 ◽  
Kinase C ◽  
Sphingosine 1 Phosphate ◽  
Protein Kinase C Inhibitor

In the present study we investigate the effect of exogenous sphingosine, sphingosine 1-phosphate and sphingosylphosphorylcholine on phospholipase D (PLD) activity in glioma C6 cells. The cells were prelabeled with [1-14C]palmitic acid and PLD-mediated synthesis of [14C]phosphatidylethanol was measured. Sphingosine 1-phosphate and sphingosylphosphorylcholine did not stimulate [14C]phosphatidylethanol formation either at low (0.1-10 microM) or high (25-100 microM) concentrations. On the other hand, sphingosine at concentrations of 100-250 microM strongly stimulated PLD activity as compared to the effect of phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA), known as a PLD activator. The effect of TPA on PLD is linked to the activation of protein kinase C. The present study also shows that sphingosine additively enhances TPA-mediated PLD activity. This is in contrast to the postulated role of sphingosine as a protein kinase C inhibitor. These results demonstrate that in glioma C6 cells sphingosine not only affects PLD independently of its effect on protein kinase C, but also is unable to block TPA-mediated PLD activity.

The Role of Ca2+ and Protein Kinase C in Regulation of Phosphatidylserine Synthesis in Glioma C6 Cells

1997 ◽  
pp. 1011-1018
Author(s):  
J. Barańska ◽  
M. Czarny ◽  
P. Sabała ◽  
M. Wiktorek
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
C6 Cells ◽  
Glioma C6 ◽  
Kinase C

Sphingosine, imipramine and propranolol stimulate phospholipase D independently of protein kinase C in glioma C6 cells

2000 ◽  
Vol 28 (5) ◽  
pp. A445-A445
Author(s):  
Marta Bobeszko ◽  
Anna Dygas ◽  
Irena Nalepa ◽  
Jolanta Barańska
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase D ◽  
C6 Cells ◽  
Glioma C6 ◽  
Kinase C

scholarly journals Targeting of Protein Kinase C-ϵ during Fcγ Receptor-dependent Phagocytosis Requires the ϵC1B Domain and Phospholipase C-γ1

2006 ◽  
Vol 17 (2) ◽  
pp. 799-813 ◽  
Author(s):  
Keylon L. Cheeseman ◽  
Takehiko Ueyama ◽  
Tanya M. Michaud ◽  
Kaori Kashiwagi ◽  
Demin Wang ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase C ◽  
Phospholipase D ◽  
Fluorescent Protein ◽  
Wild Type ◽  
Fcγ Receptor ◽  
Kinase C ◽  
Green Fluorescent

Protein kinase C-ϵ (PKC-ϵ) translocates to phagosomes and promotes uptake of IgG-opsonized targets. To identify the regions responsible for this concentration, green fluorescent protein (GFP)-protein kinase C-ϵ mutants were tracked during phagocytosis and in response to exogenous lipids. Deletion of the diacylglycerol (DAG)-binding ϵC1 and ϵC1B domains, or the ϵC1B point mutant ϵC259G, decreased accumulation at phagosomes and membrane translocation in response to exogenous DAG. Quantitation of GFP revealed that ϵC259G, ϵC1, and ϵC1B accumulation at phagosomes was significantly less than that of intact PKC-ϵ. Also, the DAG antagonist 1-hexadecyl-2-acetyl glycerol (EI-150) blocked PKC-ϵ translocation. Thus, DAG binding to ϵC1B is necessary for PKC-ϵ translocation. The role of phospholipase D (PLD), phosphatidylinositol-specific phospholipase C (PI-PLC)-γ1, and PI-PLC-γ2 in PKC-ϵ accumulation was assessed. Although GFP-PLD2 localized to phagosomes and enhanced phagocytosis, PLD inhibition did not alter target ingestion or PKC-ϵ localization. In contrast, the PI-PLC inhibitor U73122 decreased both phagocytosis and PKC-ϵ accumulation. Although expression of PI-PLC-γ2 is higher than that of PI-PLC-γ1, PI-PLC-γ1 but not PI-PLC-γ2 consistently concentrated at phagosomes. Macrophages from PI-PLC-γ2-/-mice were similar to wild-type macrophages in their rate and extent of phagocytosis, their accumulation of PKC-ϵ at the phagosome, and their sensitivity to U73122. This implicates PI-PLC-γ1 as the enzyme that supports PKC-ϵ localization and phagocytosis. That PI-PLC-γ1 was transiently tyrosine phosphorylated in nascent phagosomes is consistent with this conclusion. Together, these results support a model in which PI-PLC-γ1 provides DAG that binds to ϵC1B, facilitating PKC-ϵ localization to phagosomes for efficient IgG-mediated phagocytosis.

scholarly journals Continuous Activation of Gαq in Osteoblasts Results in Osteopenia through Impaired Osteoblast Differentiation

2007 ◽  
Vol 282 (49) ◽  
pp. 35757-35764 ◽  
Author(s):  
Naoshi Ogata ◽  
Hiroshi Kawaguchi ◽  
Ung-il Chung ◽  
Sanford I. Roth ◽  
Gino V. Segre
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Transgenic Mice ◽  
Trabecular Thickness ◽  
Kinase C ◽  
Protein Kinase C Inhibitor ◽  
Skeletal Homeostasis ◽  
Trabecular Bones ◽  
Constitutively Active

We explored the role of Gαq-mediated signaling on skeletal homeostasis by selectively expressing a constitutively active Gαq (mutation of Q209L) in osteoblasts. Continuous signaling via Gαq in mouse osteoblastic MC3T3-E1 cells impaired differentiation. Mice that expressed the constitutively active Gαq transgene in cells of the osteoblast lineage exhibited severe osteopenia in cortical and trabecular bones. Osteoblast number, bone volume, and trabecular thickness were reduced in transgenic mice, but the osteoclasts were unaffected. Osteoblasts from transgenic mice showed impaired differentiation and matrix formation. In the presence of a protein kinase C inhibitor GF109203X, this impairment was not seen, indicating mediation by the protein kinase C pathway. We propose that continuous activation of the Gαq signal in osteoblasts plays a crucial, previously unrecognized role in bone formation.

Protein kinase C is involved in cholecystokinin octapeptide-induced proliferative action in rat glioma C6 cells

Neuropeptides ◽  
1998 ◽  
Vol 32 (2) ◽  
pp. 185-189 ◽  
Author(s):  
R Kaufmann ◽  
H Schafberg ◽  
M Zieger ◽  
P Henklein ◽  
G Nowak
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
C6 Cells ◽  
Cholecystokinin Octapeptide ◽  
Rat Glioma ◽  
Glioma C6 ◽  
Kinase C

Dual regulation of sphingosine 1-phosphate-induced phospholipase D activity through RhoA and protein kinase C-α in C2C12 myoblasts

2001 ◽  
Vol 13 (8) ◽  
pp. 593-598 ◽  
Author(s):  
Elisabetta Meacci ◽  
Chiara Donati ◽  
Francesca Cencetti ◽  
Toru Oka ◽  
Issei Komuro ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase D ◽  
C2c12 Myoblasts ◽  
Kinase C ◽  
Sphingosine 1 Phosphate
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