v-Abl-mediated apoptotic suppression is associated with SHC phosphorylation without concomitant mitogen-activated protein kinase activation.
A temperature-sensitive mutant of the v-Abl protein has previously been shown to exhibit tyrosine protein kinase activity in Interleukin 3 (IL-3)-dependent IC.DP cells grown at the permissive temperature (32 degrees C) but not at the restrictive temperature (39 degrees C). These IC.DP cells are dependent on IL-3 for suppression of apoptosis at 39 degrees C, but at 32 degrees C cells will survive without added growth factor. Both IL-3 and v-Abl stimulated the tyrosine phosphorylation of SHC and GTPase-activating protein. However, while IL-3 stimulated similar levels of tyrosine phosphorylation in p46shc and p52shc, v-Abl preferentially phosphorylated p52shc, an event that occurred within 1 h of temperature switch. v-Abl also differentially associated with p46shc in a temperature-independent manner. In contrast, only IL-3 stimulated detectable increases in both myelin basic protein kinase and mitogen-activated protein (MAP) kinase kinase in in vitro assays, although in more specific MAP kinase activity assays a very slight increase in the activity of this enzyme was observed after 6 h at the permissive temperature. Time course studies suggest that phosphorylation and association of SHC with v-Abl is insufficient to lead to significant activation of MAP kinase and that activation of the MAP kinase kinase/MAP kinase pathway is not required for apoptotic suppression.
Owen-Lynch
P J
PJ
Department of Biochemistry and Applied Molecular Biology, University of Manchester, United Kingdom.
Wong
A K
AK
Whetton
A D
AD
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival; D002999:Clone Cells; D004789:Enzyme Activation; D020690:GTPase-Activating Proteins; D016313:Genes, abl; D038362:Glycogen Synthase Kinase 3; D006801:Humans; D007377:Interleukin-3 / Q000096:biosynthesis / Q000378:metabolism / Q000494:pharmacology; D007700:Kinetics; D020929:Mitogen-Activated Protein Kinase Kinases; D016296:Mutagenesis; D016374:Oncogene Proteins v-abl / Q000096:biosynthesis / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine; D011494:Protein Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D013696:Temperature; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis
D020690:GTPase-Activating Proteins; D007377:Interleukin-3; D016374:Oncogene Proteins v-abl; D011506:Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D010738:Type C Phospholipases