A Mitogen-Activated Protein Kinase-Independent Pathway Involved in the Phosphorylation and Activation of Cytosolic Phospholipase A2 in Human Neutrophils Stimulated with Tumor Necrosis Factor-α

Lipopolysaccharide induction of monocyte matrix metalloproteinases is regulated by the tyrosine phosphorylation of cytosolic phospholipase A2

“…Several other studies have pointed out the role of MAP kinases or p38 kinases in cPLA 2 phosphorylation [26,51,52] and showed a great deal of variation between cell types and type of stimulus [25,53,54]. Hence our future studies will determine the role of these and other kinases that may be involved in cPLA 2 phosphorylation in activated human monocytes.…”

Dual role of protein kinase C in the regulation of cPLA2-mediated arachidonic acid release by P2U receptors in MDCK-D1 cells: involvement of MAP kinase-dependent and -independent pathways.

“…Interestingly, in the same cell type, bradykinin receptors regulate cPLA 2 through a phosphorylationdependent mechanism that does not involve MAP kinase and PKC, but may involve a tyrosine kinase (49). Several recent studies also show that certain receptors can promote phosphorylation-dependent activation of cPLA 2 without involvement of MAP kinase and PKC, but the kinases involved remain unidentified (15,16). It appears, therefore, that the mechanisms and the protein kinases involved in the regulation of cPLA 2 vary with receptor types, even in the same cell type.…”

“…Moreover, although a role of MAP kinase has been implicated in the regulation of endogenous cPLA 2 by certain receptors (10,11), in other systems (12)(13)(14) a causal relationship between activation of endogenous cPLA 2 and AA release and activation of MAP kinase has not been established. Recent studies have suggested a dissociation between the activation of cPLA 2 and that of MAP kinase (15)(16)(17). Such results suggest that one cannot yet precisely define the relationships between activation of PKC and MAP kinase in the regulation of cPLA 2 by cellular receptors, particularly G protein-linked receptors.…”

PLIP, a Novel Splice Variant of Tip60, Interacts with Group IV Cytosolic Phospholipase A2, Induces Apoptosis, and Potentiates Prostaglandin Production

“…cPLA 2 has been shown to play a role in many physiological processes, such as ion channel regulation, cell volume regulation, macrophage eicosanoid production, and parturition (9,11,73), as well as pathophysiologic processes, such as mitochondrial dysfunction (51), allergic responses involved in asthma, atopic dermatitis and anaphylaxis, and ischemia-reperfusion injury to the brain (11,73). cPLA 2 expression has been associated with cytotoxicity (30,31,65,75).…”

“…The CaLB domain is homologous to domains found in Ras-GAP, phospholipase C, and PKC␣ (18). cPLA 2 is phosphorylated at a number of sites, including Ser-505, and activated by ERK1/2 (48,54) and p38 mitogenactivated protein kinase (75).…”