Cellular signaling events elicited by v-abl associated with growth factor independence in an interleukin-3-dependent cell line.
A temperature-sensitive mutant of the v-abl oncoprotein has previously been shown to have markedly reduced tyrosine protein kinase activity in interleukin 3 (IL-3)-dependent cells grown at restrictive (39 degrees C), compared to permissive (32 degrees C) temperatures. Transfection of this mutant v-abl into the IC2.9 cell line, generated the IC.DP subclone which was dependent on IL-3 for survival at 39 degrees C, but not at 32 degrees C. Furthermore, IC.DP cells cultured at 32 degrees C exhibited IL-3-independent thymidine incorporation, which was not apparent at 39 degrees C. Switching cells from the restrictive to the permissive temperature resulted in an increase in cellular inositol-1,4,5-trisphosphate, choline phosphate and diacylglycerol levels in the IC.DP cell line. These increases were only observed after a lag period of 4 h. Within 2 h of switching IC.DP cells previously maintained at 32 to 39 degrees C, there was a significant decrease in all three metabolites. Temperature switches had no effect upon these metabolites in the parent IC2.9 cell line. Down-regulation of protein kinase C inhibited v-abl-stimulated DNA synthesis in IC.DP cells cultured at 32 degrees C. IC.DP cells cultured at 32 degrees C were found to have a constitutively activated Na+/H+ antiport, although this activation was inhibited by the down-modulation of protein kinase C. These data indicate a role for phospholipid hydrolysis and protein kinase C activation in V-ABL-mediated abrogation of IL-3 dependence.
Department of Biochemistry and Applied Molecular Biology, University of Manchester, United Kingdom.
P J
PJ
Owen
P
P
Musk
C A
CA
Evans
A D
AD
Whetton
D002352:Carrier Proteins / Q000378:metabolism; D002455:Cell Division; D002460:Cell Line; D016313:Genes, abl; D006133:Growth Substances / Q000378:metabolism*; D007377:Interleukin-3 / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction; D017923:Sodium-Hydrogen Exchangers
D002352:Carrier Proteins; D006133:Growth Substances; D007377:Interleukin-3; D010743:Phospholipids; D017923:Sodium-Hydrogen Exchangers; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C