A 32-kD GTP-binding protein associated with the CD4-p56lck and CD8-p56lck T cell receptor complexes |
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Authors: | J C Telfer C E Rudd |
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Institution: | Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA. |
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Abstract: | The guanosine triphosphate (GTP)-binding proteins include signal-transducing heterotrimeric G proteins (for example, Gs, Gi), smaller GTP-binding proteins that function in protein sorting, and the oncogenic protein p21ras. The T cell receptor complexes CD4-p56lck and CD8-p56lck were found to include a 32- to 33-kilodalton phosphoprotein (p32) that was recognized by an antiserum to a consensus GTP-binding region in G proteins. Immunoprecipitated CD4 and CD8 complexes bound GTP and hydrolyzed it to guanosine diphosphate (GDP). The p32 protein was covalently linked to alpha-32P]GTP by ultraviolet photoaffinity labeling. These results demonstrate an interaction between T cell receptor complexes and an intracellular GTP-binding protein. |
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