Human interleukin-3 stimulates a phosphatidylcholine specific phospholipase C and protein kinase C translocation.
Human interleukin-3 binds to a high affinity receptor composed of alpha- and beta-subunits. The beta-subunit is responsible for signal transduction but does not contain any intrinsic tyrosine kinase activity or other consensus motifs related to intracellular signaling. Previous work using IL-3 dependent MO7E cells has suggested a major role only for non-receptor tyrosine kinase activation in IL-3 signal transduction. We have shown, however, that engagement of the human interleukin-3 receptor induces the translocation of protein kinase C from the cytosol to the cell membrane in MO7E cells. This translocation is accompanied by rapid (2-5 min) accumulation of 1'2'-diacylglycerol (twice control values) in the absence of an increase in intracellular Ca2+. Prelabeling cells with [3H]glycerol or [3H]-choline demonstrated rapid release of [3H]phosphorylcholine and a decrease in [3H]glycerol-labeled phosphatidylcholine in response to IL-3 stimulation. In addition, IL-3 did not induce phosphatidic acid accumulation, and the IL-3 induced diacylglycerol accumulation was blocked by p-bromophenacylbromide (a phospholipase C inhibitor). It is thus likely that interleukin-3 is activating a phosphatidylcholine specific phospholipase C rather than a phospholipase D. Finally, genistein and herbimycin, specific tyrosine kinase inhibitors, inhibited both IL-3 induced protein kinase C translocation and the accumulation of diacylglycerol. Thus, IL-3 induced tyrosine phosphorylation may result in activation of a phosphatidylcholine phospholipase C and protein kinase C.
Rao
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American Red Cross, Holland Laboratory, Cell Biology Department, Rockville, MD 20855.
Mufson
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D000595:Amino Acid Sequence; D016227:Benzoquinones; D002462:Cell Membrane / Q000201:enzymology; D004075:Diglycerides / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D019833:Genistein; D006801:Humans; D006868:Hydrolysis; D007377:Interleukin-3 / Q000494:pharmacology*; D007529:Isoflavones / Q000494:pharmacology; D047029:Lactams, Macrocyclic; D008969:Molecular Sequence Data; D010712:Phosphatidic Acids / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism*; D011493:Protein Kinase C / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D011809:Quinones / Q000494:pharmacology; D017828:Rifabutin / Q000031:analogs & derivatives; D012680:Sensitivity and Specificity; D013268:Stimulation, Chemical; D013920:Thrombocythemia, Essential / Q000201:enzymology; D014178:Translocation, Genetic / Q000187:drug effects*; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism
C011439:1,2-diacylglycerol; D016227:Benzoquinones; D004075:Diglycerides; D007377:Interleukin-3; D007529:Isoflavones; D047029:Lactams, Macrocyclic; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D011809:Quinones; D017828:Rifabutin; C020754:herbimycin; D019833:Genistein; D011493:Protein Kinase C; D010738:Type C Phospholipases