scholarly journals Differential Activation of Cytosolic Phospholipase A2(cPLA2) by Thrombin and Thrombin Receptor Agonist Peptide in Human Platelets. EVIDENCE FOR ACTIVATION OF cPLA2INDEPENDENT OF THE MITOGEN-ACTIVATED PROTEIN KINASES ERK1/2

1995 ◽  
Vol 270 (24) ◽  
pp. 14816-14823 ◽  
Author(s):  
Ruth M. Kramer ◽  
Edda F. Roberts ◽  
Paul A. Hyslop ◽  
Barbara G. Utterback ◽  
Kwan Y. Hui ◽  
...  
Keyword(s):  
Phospholipase A2 ◽  
Protein Kinases ◽  
Receptor Agonist ◽  
Human Platelets ◽  
Cytosolic Phospholipase A2 ◽  
Thrombin Receptor ◽  
Mitogen Activated Protein Kinases ◽  
Agonist Peptide ◽  
Cytosolic Phospholipase ◽  
Mitogen Activated Protein

scholarly journals Thrombin produces phosphorylation of cytosolic phospholipase A2 by a mitogen-activated protein kinase kinase-independent mechanism in the human astrocytoma cell line 1321N1

1997 ◽  
Vol 328 (1) ◽  
pp. 263-269 ◽  
Author(s):  
Marita HERNÁNDEZ ◽  
Yolanda BAYÓN ◽  
Mariano SÁNCHEZ CRESPO ◽  
María Luisa NIETO
Keyword(s):  
Phospholipase A2 ◽  
Map Kinase ◽  
Cell Line ◽  
Cytosolic Phospholipase A2 ◽  
Thrombin Receptor ◽  
Primary Sequence ◽  
Jun Kinase ◽  
Cytosolic Phospholipase ◽  
Astrocytoma Cell ◽  
Mitogen Activated Protein

The release of [3H]arachidonic acid was studied in the 1321N1 astrocytoma cell line upon stimulation with thrombin. The effect of thrombin was antagonized by hirudin only when both compounds were added simultaneously, which suggests activation of thrombin receptor. Evidence that the cytosolic phospholipase A2 (cPLA2) takes part in thrombin-induced arachidonate release was provided by the finding that thrombin induced retardation of the mobility of cPLA2 in SDS/polyacrylamide gels, which is a feature of the activation of cPLA2 by mitogen-activated protein (MAP) kinases. Thrombin induced activation of two members of the MAP kinase family whose consensus primary sequence appears in cPLA2, namely p42-MAP kinase and c-Jun kinase. However, the activation of c-Jun kinase preceded the phosphorylation of cPLA2 more clearly than the activation of p42-MAK kinase did. Both cPLA2 and c-Jun kinase activation were not affected by PD-98059, a specific inhibitor of MAP kinase kinases, which indeed completely blocked p42-MAP kinase shift. Heat shock, a well-known activator of c-Jun kinase, also phosphorylated cPLA2 but not p42-MAP kinase. These data indicate the existence in astrocytoma cells of a signalling pathway triggered by thrombin receptor stimulation that activates a kinase cascade acting on the Pro-Leu-Ser-Pro consensus primary sequence, activates cPLA2, and associates the release of arachidonate with nuclear signalling pathways.

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