title: Nerve growth factor-induced decrease in the cell-free phosphorylation of a soluble protein in PC12 cells.
abstract: Incubation of cell-free extracts from PC12 cells with [32P]ATP leads to the phosphorylation of a 100,000-dalton protein. In extracts from cells treated with nerve growth factor, the labeling of the 100,000-dalton protein is substantially and selectively reduced. Direct quantitation indicates that the reduction is a minimum of 30-50% in the various experiments. The decrease is evident after as little as 15 min of nerve growth factor treatment, and disappears within 2 h after the removal of nerve growth factor. The decrease is dose dependent; a complete response is seen after treatment with 10 ng of nerve growth factor/ml. Some decrease in phosphorylation is also seen after treatment of the cells with epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, or 5'-N-ethylcarboxamideadenosine, a potent adenosine receptor agonist, but not after treatment with insulin. The phosphorylation of the 100,000-dalton protein, in extracts from either control or nerve growth factor-treated cells, leads almost exclusively to the formation of phosphothreonine. The addition of equal amounts of extract from untreated cells and extract from nerve growth factor-treated cells produces a level of phosphorylation exactly intermediate between those of the two extracts used separately, indicating the absence of a soluble kinase inhibitor. The data suggest that nerve growth factor treatment produces either a covalent inhibition or a physical removal of the kinase for the 100,000-dalton protein.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D002460:Cell Line; D002474:Cell-Free System; D000242:Cyclic AMP / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005728:Ganglia, Sympathetic / Q000378:metabolism; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010673:Pheochromocytoma / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors; D051381:Rats; D009418:S100 Proteins / Q000378:metabolism*
chemical_list: D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D047428:Protein Kinase Inhibitors; D009418:S100 Proteins; D019830:Adenosine-5'-(N-ethylcarboxamide); D004815:Epidermal Growth Factor; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D000241:Adenosine