In:
Journal of Cell Science, The Company of Biologists, Vol. 113, No. 8 ( 2000-04-15), p. 1335-1343
Abstract:
The signal transduction involved in the purinergic stimuli- induced activation of protein kinase C (PKC) in CHO-K1 cells was investigated. Purinergic stimuli such as adenosine triphosphate and uridine triphosphate induced a transient translocation of PKC ε, γ, and δ from the cytoplasm to the plasma membrane. These translocations were blocked by an inhibitor of phosphatidylinositol-specific phospholipase C (PLC), but not by an inhibitor of phosphatidylcholine- specific PLC. A diacylglycerol (DAG) analogue also induced reversible translocations of PKC γ, ε, and δ from the cytoplasm to the plasma membrane, while the calcium ionophore A23187 caused a similar translocation of only the γ subtype. These results confirm that the hydrolysis of phosphatidylinositol-2-phosphate by PLC and the subsequent generation of DAG and increase in Ca2+ are involved in the purinergic stimuli-induced translocation of PKC. A DAG antagonist, 1-o-hexadecyl-2-o-acetyl-glycerol, blocked the DAG analogue-induced translocations of all PKC subtypes tested but failed to inhibit the purinergic stimuli-induced translocations of PKC ε and γ. The DAG antagonist could not block the ATP- and UTP-induced translocation of PKC ε even in the absence of extracellular Ca2+. Co-application of the DAG antagonist and a phospholipase A2 (PLA2) inhibitor such as aristolochic acid, arachidonyltrifluoromethyl ketone, or bromoenol lactone inhibited the purinergic receptor-mediated translocation of PKC ε although each PLA2 inhibitor alone did not block the translocation. In contrast to the ε subtype, ATP-induced translocation of PKC γ was observed in the presence of both the PLA2 inhibitor and the DAG antagonist. However, it is noteworthy that re-translocation of PKC γ was hastened by the PLA2 inhibitor. Furthermore products of PLA2, such as lysophospholipids and fatty acids, induced the translocation of PKC γ and ε in a dose dependent manner, but not δ. These results indicate that, in addition to PLC and DAG, PLA2 and its products are involved in the purinergic stimuli-induced translocation of PKC ε and γ in CHO-K1 cells. Each subtype of PKC in CHO-K1 cell is individually activated in response to a purinergic stimulation.
Type of Medium:
Online Resource
ISSN:
0021-9533
,
1477-9137
DOI:
10.1242/jcs.113.8.1335
Language:
English
Publisher:
The Company of Biologists
Publication Date:
2000
detail.hit.zdb_id:
219171-4
detail.hit.zdb_id:
1483099-1
SSG:
12
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