Abstract
The cellular response to 1-beta-D-arabinofuranosylcytosine (ara-C) includes activation of Jun/AP-1, induction of c-jun transcription, and programmed cell death. The stress-activated protein (SAP) kinases stimulate the transactivation function of c-jun by amino terminal phosphorylation. The present work demonstrates that ara-C activates p54 SAP kinase. The finding that SAP kinase is also activated by alkylating agents (mitomycin C and cisplatinum) and the topoisomerase I inhibitor 9-amino-camptothecin supports DNA damage as an initial signal in this cascade. The results demonstrate that ara-C also induces binding of SAP kinase to the SH2/SH3-containing adapter protein Grb2. SAP kinase binds to the SH3 domains of Grb2, while interaction of the p85 alpha-subunit of phosphatidylinositol 3-kinase complex. The results also demonstrate that ara-C treatment is associated with inhibition of lipid and serine kinase activities of PI 3-kinase. The potential significance of the ara-C-induced interaction between SAP kinase and PI 3-kinase is further supported by the demonstration that Wortmannin, an inhibitor of PI 3-kinase, stimulates SAP kinase activity. The finding that Wortmannin treatment is also associated with internucleosomal DNA fragmentation may support a potential link between PI 3-kinase and regulation of both SAP kinase and programmed cell death.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Androstadienes / pharmacology
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Antimetabolites, Antineoplastic / toxicity*
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Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
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Cell Line
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Cytarabine / toxicity*
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DNA Damage*
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Enzyme Activation
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Enzyme Inhibitors / pharmacology
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GRB2 Adaptor Protein
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Glutathione Transferase / metabolism
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Humans
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JNK Mitogen-Activated Protein Kinases
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Leukemia, Myeloid
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Mitogen-Activated Protein Kinases*
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Phosphatidylinositol 3-Kinases
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Phosphotransferases (Alcohol Group Acceptor) / metabolism
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Protein Kinases / isolation & purification
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Protein Kinases / metabolism*
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Proteins / metabolism
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Proto-Oncogene Proteins c-jun / isolation & purification
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Proto-Oncogene Proteins c-jun / metabolism
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / metabolism
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Stress, Physiological
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Tumor Cells, Cultured
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Wortmannin
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p38 Mitogen-Activated Protein Kinases
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src Homology Domains
Substances
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Adaptor Proteins, Signal Transducing
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Androstadienes
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Antimetabolites, Antineoplastic
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Enzyme Inhibitors
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GRB2 Adaptor Protein
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GRB2 protein, human
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Proteins
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Proto-Oncogene Proteins c-jun
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Recombinant Proteins
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Cytarabine
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Glutathione Transferase
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Protein Kinases
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Phosphatidylinositol 3-Kinases
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Phosphotransferases (Alcohol Group Acceptor)
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Calcium-Calmodulin-Dependent Protein Kinases
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JNK Mitogen-Activated Protein Kinases
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Mitogen-Activated Protein Kinases
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p38 Mitogen-Activated Protein Kinases
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Wortmannin