The P34G mutation reduces the transforming activity of K-Ras and N-Ras in NIH 3T3 cells but not of H-Ras
Ras proteins (H-, N-, and K-Ras) operate as molecular switches in signal transduction cascades controlling cell proliferation, differentiation, or apoptosis. The interaction of Ras with its effectors is mediated by the effector-binding loop, but different data about Ras location to plasma membrane s...
| Autores: | , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2004 |
| País: | España |
| Institución: | Instituto de Salud Carlos III (ISCIII) |
| Repositorio: | Repisalud |
| Idioma: | inglés |
| OAI Identifier: | oai:repisalud.isciii.es:20.500.12105/9698 |
| Acceso en línea: | http://hdl.handle.net/20.500.12105/9698 |
| Access Level: | acceso abierto |
| Palabra clave: | Animals Binding Sites DNA-Binding Proteins Enzyme Activation Gene Expression Genes, ras Humans Mice Mitogen-Activated Protein Kinase 1 Mitogen-Activated Protein Kinase 3 Mitogen-Activated Protein Kinases NIH 3T3 Cells Phosphatidylinositol 3-Kinases Phospholipase D Protein Isoforms Protein-Serine-Threonine Kinases Proto-Oncogene Proteins Proto-Oncogene Proteins c-akt Proto-Oncogene Proteins c-raf Signal Transduction Structure-Activity Relationship Transcription Factors Transfection ets-Domain Protein Elk-1 rac1 GTP-Binding Protein ral GTP-Binding Proteins ral Guanine Nucleotide Exchange Factor ras Proteins Mutation |
| Sumario: | Ras proteins (H-, N-, and K-Ras) operate as molecular switches in signal transduction cascades controlling cell proliferation, differentiation, or apoptosis. The interaction of Ras with its effectors is mediated by the effector-binding loop, but different data about Ras location to plasma membrane subdomains and new roles for some docking/scaffold proteins point to signaling specificities of the different Ras proteins. To investigate the molecular mechanisms for these specificities, we compared an effector loop mutation (P34G) of three Ras isoforms (H-, N-, and K-Ras4B) for their biological and biochemical properties. Although this mutation diminished the capacity of Ras proteins to activate the Raf/ERK and the phosphatidylinositol 3-kinase/AKT pathways, the H-Ras V12G34 mutant retained the ability to cause morphological transformation of NIH 3T3 fibroblasts, whereas both the N-Ras V12G34 and the K-Ras4B V12G34 mutants were defective in this biological activity. On the other hand, although both the N-Ras V12G34 and the K-Ras4B V12G34 mutants failed to promote activation of the Ral-GDS/Ral A/PLD and the Ras/Rac pathways, the H-Ras V12G34 mutant retained the ability to activate these signaling pathways. Interestingly, the P34G mutation reduced specifically the N-Ras and K-Ras4B in vitro binding affinity to Ral-GDS, but not in the case of H-Ras. Thus, independently of Ras location to membrane subdomains, there are marked differences among Ras proteins in the sensitivity to an identical mutation (P34G) affecting the highly conserved effector-binding loop. |
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