Evidence for a platelet-activating factor receptor on human lymphoblastoid B cells: activation of the phosphatidylinositol cycle and induction of calcium mobilization.
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.
Schulam
P G
PG
Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030.
Putcha
G
G
Franklin-Johnson
J
J
Shearer
W T
WT
D001402:B-Lymphocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D006801:Humans; D008563:Membrane Lipids / Q000378:metabolism; D010712:Phosphatidic Acids / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010972:Platelet Activating Factor / Q000031:analogs & derivatives / Q000494:pharmacology*; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled
D008563:Membrane Lipids; C029271:O-deacetyl platelet activating factor; D010712:Phosphatidic Acids; D010716:Phosphatidylinositols; D010972:Platelet Activating Factor; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; C039351:platelet activating factor receptor; D002118:Calcium