Evidence for a platelet-activating factor receptor on human lymphoblastoid B cells: activation of the phosphatidylinositol cycle and induction of calcium mobilization |
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Authors: | P G Schulam G Putcha J Franklin-Johnson W T Shearer |
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Affiliation: | Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030. |
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Abstract: | In this report we demonstrate evidence which strongly suggests that a receptor for platelet-activating factor (PAF) exists on a lymphoblastoid B cell line, LA350. PAF ranging in concentration from 10(-6)-10(-9)M initiated the incorporation of 32P into phosphatidic acid (PA) and phosphatidylinositol (PI) with no change in phosphatidylethanolamine (PE) and phosphatidylcholine (PC) over baseline. Lyso-PAF, the inactive precursor, at 10(-7)M had no effect on membrane phospholipid metabolism. In addition, PAF from 10(-6)-10(-8)M when added to Fura-2 containing B cells induced a rapid and significant rise of calcium within the cell, with lyso-PAF having no effect. These data suggest that PAF binds to a receptor on B cells and induces the hydrolysis of PI and a subsequent increase of intracellular calcium. |
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