An important new mechanism in the regulation platelet aggregation was uncovered with the discovery of the protein kinase-C mediated activation of the """"""""release"""""""" reaction from platelet granules. The activation of protein kinase-C leads to the phosphorylation of a 40 KD protein presumed to be necessary for the release of various platelet proaggregatory substances from the granules. Indeed platelets can be activated towards aggregation by the simple addition of certain diglycerides. This new kinase is transiently activated by the presence of 1,2-sn-diglycerides, which are themselves products of polyphosphatidylinositol turnover. This specific activation by 1,2-sn-diglycerides means that specific antagonists of this enzyme can be designed. It is the purpose of this grant request to explore the medicinal chemistry of protein kinase-C activation and inhibition. Novel diglyceride analogs will be synthesized and structure-activity studies on these molecules as agonists and antagonists of protein kinase-C activity will be performed. The prototypical structures of agonists and antagonists will be determined. Both kinds of molecules will be tested for their activities to cause and interfere with platelet aggregation in vitro. Active antagonists will serve as a basis for the rational design of drugs which interfere with platelet aggregation to be utilized as antithrombotic drugs in the treatment of thrombotic and thromboembolic disease primarily of the arterial type.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
Project #
Application #
Study Section
Bio-Organic and Natural Products Chemistry Study Section (BNP)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Harvard University
Schools of Medicine
United States
Zip Code
Ma, Y T; Gilbert, B A; Rando, R R (1995) Farnesylcysteine analogs to probe role of prenylated protein methyltransferase. Methods Enzymol 250:226-34
Gilbert, B A; Lim, Y H; Ding, J et al. (1995) Farnesyl thiotriazole, a potent neutrophil agonist and structurally novel activator of protein kinase C. Biochemistry 34:3916-20
Ding, J; Lu, D J; Perez-Sala, D et al. (1994) Farnesyl-L-cysteine analogs can inhibit or initiate superoxide release by human neutrophils. J Biol Chem 269:16837-44
Ma, Y T; Shi, Y Q; Lim, Y H et al. (1994) Mechanistic studies on human platelet isoprenylated protein methyltransferase: farnesylcysteine analogs block platelet aggregation without inhibiting the methyltransferase. Biochemistry 33:5414-20
Shi, Y Q; Rando, R R (1992) Kinetic mechanism of isoprenylated protein methyltransferase. J Biol Chem 267:9547-51
Rando, R R; Kishi, Y (1992) Structural basis of protein kinase C activation by diacylglycerols and tumor promoters. Biochemistry 31:2211-8
Kong, F H; Kishi, Y; Perez-Sala, D et al. (1991) The pharmacophore of debromoaplysiatoxin responsible for protein kinase C activation. Proc Natl Acad Sci U S A 88:1973-6
Kong, F; Kishi, Y; Perez-Sala, D et al. (1990) The stereochemical requirement for protein kinase C activation by 3-methyldiglycerides matches that found in naturally occurring tumor promoters aplysiatoxins. FEBS Lett 274:203-6
Nakamura, H; Kishi, Y; Pajares, M A et al. (1989) Structural basis of protein kinase C activation by tumor promoters. Proc Natl Acad Sci U S A 86:9672-6
Rando, R R (1988) Regulation of protein kinase C activity by lipids. FASEB J 2:2348-55

Showing the most recent 10 out of 11 publications