Decrease in Coupling of Gs in v-src-Transformed NIH-3T3 Fibroblasts: Possible Involvement of Tyrosine Phosphorylation of Gs by pp60v-src
| Autor: | Y. Tokumitsu, Yasuyuki Nomura, H. Akiho, M. Noda |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Gs alpha subunit
G protein Biophysics In Vitro Techniques Biology Biochemistry Oncogene Protein pp60(v-src) Adenylyl cyclase Mice chemistry.chemical_compound GTP-Binding Proteins Receptors Adrenergic beta Cyclic AMP Animals Iodocyanopindolol Phosphorylation Phosphotyrosine Protein kinase A Molecular Biology Membrane Proteins Tyrosine phosphorylation 3T3 Cells Protein-Tyrosine Kinases Cell Transformation Viral Phosphoproteins Molecular biology Genes src chemistry Pindolol v-Src Tyrosine Adenylyl Cyclases Signal Transduction Proto-oncogene tyrosine-protein kinase Src |
| Zdroj: | Archives of Biochemistry and Biophysics. 304:235-241 |
| ISSN: | 0003-9861 |
| Popis: | In Rous sarcoma virus (RSV)-transformed NIH-3T3 fibroblasts expressing pp60 v- src as tyrosine protein kinase, isoproterenol-stimulated cAMP accumulation was much lower than in normal cells. The reduction in v- src -transformed cells seemed to be mainly due to a decrease in the number of β 2 -adrenoceptors. When the membranes were phosphorylated with ATP, however, the binding affinity of isoproterenol to β 2 -adrenoceptors was reduced in transformed cell membranes by 34% compared to that in normal cell membranes. The reduction in transformed cell membranes was restored to the level of normal cell membranes by treatment of membranes with anti-pp60 v- src antibody. GTPγS- and cholera toxin-stimulated adenylyl cyclase activities were reduced with no change in forskolin-stimulated adenylyl cyclase activity in transformed cell membranes. The reduced effect of GTPγS was also restored by treatment with anti-pp60 v- src antibody or by adding staurosporine, which inhibits a variety of protein kinases, including tyrosine protein kinase. One of the 32 P-phosphoproteins phosphorylated with [γ- 32 P]ATP in v- src -transformed cell membranes was bound to GTP-agarose, and was a 46-kDa molecule on a sodium dodecyl sulfate-polyacrylamide gel. This 46-kDa 32 P-labeled phosphoprotein was immunoprecipitated with anti-phosphotyrosine antibody or anti-stimulatory GTP-binding protein (anti-G s ) antibody. These results suggest that pp60 v- src phosphorylates the α-subunit of G s and consequently causes a decrease in the coupling of β 2 -receptors to G s and in the coupling of G s to adenylyl cyclase. |
| Databáze: | OpenAIRE |
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