Phospholipases and acyltransferases in macrophages.
In contrast to many other cells, macrophages contain a phospholipase A2, which preferentially liberates arachidonic acid from the main phospholipids. In unstimulated macrophages this acylchain-specific phospholipase A2 is localized in the lipid-free cytosol and thus without function. After activation of protein kinase C with diacylglycerols, the cytosolic phospholipase A2 is translocated to cellular membranes. The same activator of protein kinase C causes an inhibition of the acyl-CoA: lysophosphatide acyltransferase. This enzyme regulates the availability of free arachidonic acid for eicosanoid synthesis by reacylation into phospholipids. Thus protein kinase C seems to regulate the level of free arachidonic acid by opposite effects on the two major enzymes, which are responsible for the control of free arachidonic acid.
Flesch
I
I
Max-Planck-Institut für Immunbiologie, Freiburg.
Schonhardt
T
T
Ferber
E
E
D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000378:metabolism; D000217:Acyltransferases / Q000378:metabolism*; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D006801:Humans; D008264:Macrophages / Q000201:enzymology*; D010740:Phospholipases / Q000378:metabolism*
D001095:Arachidonic Acids; D016718:Arachidonic Acid; D000217:Acyltransferases; D008243:1-Acylglycerophosphocholine O-Acyltransferase; D010740:Phospholipases