Direct activation of phospholipase A2 by GTP-binding protein in human peripheral polymorphonuclear leukocytes. |
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| Authors: | M Ando H Furui K Suzuki F Taki K Takagi |
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| Institution: | 2nd Department of Internal Medicine, Nagoya University School of Medicine, Japan. |
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| Abstract: | In human peripheral polymorphonuclear leukocyte (PMN), 10% of PLA2 activity was found in the particulate fraction. In the particulate fraction, the activity of phospholipase A2 was enhanced 270% by 100 microM guanosine 5'-gamma-thio]triphosphate, a hydrolysis-resistant analog of GTP. In the soluble fraction, such enhancement was not observed. Guanosine 5'-beta-thio]diphosphate (2 mM), which irreversibly inactivates GTP-binding protein, blocked the enhancement in the particulate fraction. Membrane-binding phospholipase A2 activity of PMN would thus appear to be regulated directly by GTP-binding protein. |
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