Kinase diglyceride

Other enzymes present in myelin include those involved in phosphoinositide metabolism phosphatidylinositol kinase, diphosphoinositide kinase, the corresponding phosphatases and diglyceride kinases. These are of interest because of the high concentration of polyphosphoinositides of myelin and the rapid turnover of their phosphate groups. This area of research has expanded towards characterization of signal transduction system(s), with evidence of G proteins and phospholipases C and D in myelin. 

This enzyme [EC 2.7.1.107], also known as diglyceride kinase, catalyzes the reaction of ATP with a 1,2-diacyl-... 

DIEEUSION WITHIN CELLULAR/ EXTRACELLULAR SPACES Diglyceride kinase,... 

Daleo, G.R. Piras, M.M. Piras, R. Diglyceride kinase activity of microtubules. Characterization and comparison with the protein kinase and ATPase activities associated with vinblastine-isolated tubulin of chick embryonic muscles. Eur. J. Biochem., 68, 339-346 (1976)... 

Bohnenberger, E. Sandermann, H. Diglyceride kinase from Escherichia coli. Purification in organic solvent and some properties of the enzyme. Eur. J. Biochem., 94, 401-407 (1979)... 

Studies on brain have led to new interpretation of the relationship between phosphatidic acid and the sodium pump. The incorporation of into the endoplasmic reticulum of brain is stimulated by acetylcholine, ATP, and diglyceride kinase. Sodium is an absolute requirement for this effect. The addition of sodium to the medium stimulates the incorporation of P into phosphatidic acid, in contrast to potassium, which has no effect. 

Perry, DK, Bielawska, A and Hannun, YA (2000a) Quantitative determination of ceramide using diglyceride kinase. Methods Enzymol, 312, 22-31. 

It is also known from the work of Hokin and Hokin (1959) and Strickland (1962) that phosphatidic acid may be formed by the phosphorylation of D-a, jS-diglyceride from ATP, a reaction catalysed by the enzyme diglyceride kinase ... 

Terbush DR, Holz RW (1986) Effects of phorbol esters, diglyceride, and cholinergic agonists on the subcellular distribution of protein kinase C in intact or digitonin-permeabilized adrenal chromaffin cells. J Biol Chem 261 17099-106... 

IP3 is classified now as a second messenger with considerable influence on calcium movement from intracellular stores in a cell. Furthermore, diglycerides have a considerable and important effect on protein kinase C activity and location (Nishizuka, 1992). This is a classic example of an inactive (precursor) molecule being converted to a biologically active product. This reaction is an excellent example of the role of phospholipids in membrane processes through an enzyme-catalyzed reaction. 

PAF receptor is coupled to the activation of both protein kinase C and tyrosine kinase (Shukla, 1992, Izumi and Shimizu, 1995). PAF receptor antagonists block both pathways. The activation of PKC is through the Imown PLC generated diglyceride -t- Ca pathway (leyasu et. al. 1982). Activation of PKC in platelets (eg. by phrobol myristate acetates) inhibited PAF stimulation of platelets. On the other hand PKC inhibitors (eg. staurosporine) enhanced PAF stimulated IP, production. In rabbit platelets PKC activation by PAF was suggested to be independent of enzyme translocation (Pelech et. al. 1990). Human platelets have 6 PKC isozymes (alpha, p, 8, zeta, eta and theta). PAF stimulated 200% and 175% increase in the levels of membrane - bound PKC eta and theta... 

The 2,4-dinitrobenzyl diglyceride (85) has been synthesized as a means of photoactivating protein kinase C (PKC). PKC is inactive in the cytoplasm until its primary activator, a diacylglycerol, is produced by phospholipase C. Upon photolysis (85) releases dioctanoylglycerol, and thus provides an approach to the controlled activation of PKC. 

Although it is beyond the scope of this chapter to review all the effects of protein kinase C-mediated phosphorylation of cellular constituents, it is important to realize that the synergistic actions of diglyceride and calcium ion on protein kinase C activity have profound biological sequelae. 

Precursors of membrane phospholipids are diglycerides formed from glycerol 3-phosphate. These molecules are made by reducing dihydroxyacetone phosphate from glycolysis with NADH in the cytoplasm. In the liver, glycerol 3-phosphate is also produced from glycerol itself by ATP-dependent phosphorylation via glycerol kinase. This enzyme is notably absent from other tissues. 

Bass, DA, McPhail, LC, Schmitt, ID, Morris-Natschke, S, McCall, CE and Wykle, RL (1988) Selective priming of rate and duration of the respiratory burst of neutrophils by 1,2-diacyl and 1 -O-alkyl-2-acyl diglycerides. Possible relation to effects on protein kinase C. Journal of Biological Chemistry, 263, 19610-19617. 

Ford, DA, Miyake, R, Glaser, PE and Gross, RW (1989) Activation of protein kinase C by naturally occurring ether-linked diglycerides. J Biol Chem, 264, 13818-13824. 

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