AN EVALUATION OF THE ROLE OF PHOSPHOLIPASE D ENZYMES IN BLOOD CELLS AND POSSIBLE IMPLICATIONS FOR HEALTH HOMEOSTASIS
*Manoj G. Tyagi
The enzyme Phospholipase D (PLD) is expressed in many blood cells like the erythrocytes, lymphocytes and platelets and may have critical roles in physiology and patho-physiology. The major substrate for the action of PLD is the Phosphatidylcholine. This enzymatic pathway induces the production of phosphatidic acid selectively. Phosphatidic acid is the precursor for diacylglycerol and lysophosphatidic acid. On the other hand, Guanine nucleotides also stimulate PLD enzyme in blood cells. Furthermore, tyrosine kinase may also be involved in platelet PLD regulation. It seems that multiple signals acting sequentially or in parallel converge on PLD enzyme. PLD is also present in platelet percursormegakaryocytric cells and can be activated by platelet agonists. In these cells both PKC and G-proteins (e.g. Rho) may regulate PLD activity. The significance of PLD in blood cells still requires thorough investigation. Recent research offer new avenues to further elucidate the biochemistry of this enzyme in blood cells. This review investigates the role of phospholipase D enzyme in lymphocytes and its implications in health homeostasis.
Keywords: Phospholipase D, lymphocytes, platelets, erythrocytes, growth factors, enzyme.
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