AJP - Endocrinology and Metabolism, Vol 261, Issue 1 E109-E114, Copyright © 1991 by American Physiological Society

ARTICLES

Differential effects of omega-3 fish oils on protein kinase activities in vitro

L. A. Speizer, M. J. Watson and L. L. Brunton
Department of Pharmacology, University of California School of Medicine, San Diego, La Jolla 92093.

We studied the in vitro effects of omega-3 fish oils and other fatty acids on the activity of crude protein kinase C from S49 lymphoma cells, on partially purified enzyme from rat cerebrum, on homogeneous protein kinase C from bovine brain, and, for comparison, on type I adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase. In the absence of exogenous phospholipid, the fish oils cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and acid (DCHA) enhance the catalytic cis-4,7,10,13,16,19-docosahexaenoic activity of protein kinase C and support the binding of [3H]phorbol 12,13-dibutyrate, both to approximately 50% of the level supported by phosphatidylserine. In the presence of phosphatidylserine, the omega-3 fatty acids reduce catalytic activity and [3H]phorbol 12,13-dibutyrate binding by about one-half. The effects of the omega-3 fatty acids on enzyme activity suggest that fish oils act as partial agonists competitively with phosphatidylserine. EPA, DCHA, and arachidonate (but not a variety of saturated fatty acids) inhibit the cAMP-dependent protein kinase. Thus dietary fish oils and cellular fatty acids mobilized by the action of phospholipase A2 may differentially modulate the activities of protein kinase C and cAMP-dependent protein kinase. These data suggest means by which unsaturated fatty acids mobilized within cells may act as second messengers.

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				B. Mirnikjoo, S. E. Brown, H. F. S. Kim, L. B. Marangell, J. D. Sweatt, and E. J. Weeber Protein Kinase Inhibition by omega -3 Fatty Acids J. Biol. Chem., March 30, 2001; 276(14): 10888 - 10896. [Abstract] [Full Text] [PDF]