Exchange Factors of the RasGRP Family Mediate Ras Activation in the Golgi
| Autor: | María J. Caloca, Xosé R. Bustelo, José L. Zugaza |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Amino Acid Motifs
Genetic Vectors Molecular Sequence Data Golgi Apparatus Guanosine GTPase Biology Endoplasmic Reticulum Transfection Biochemistry Cell Line Mice symbols.namesake chemistry.chemical_compound Anti-apoptotic Ras signalling cascade Animals Guanine Nucleotide Exchange Factors Endomembrane system Amino Acid Sequence HRAS Molecular Biology Sequence Homology Amino Acid Cell Membrane Zinc Fingers 3T3 Cells Cell Biology Golgi apparatus Cell biology DNA-Binding Proteins Microscopy Fluorescence chemistry COS Cells ras Proteins symbols Guanosine Triphosphate Guanine nucleotide exchange factor Signal transduction Plasmids Signal Transduction |
| Zdroj: | Journal of Biological Chemistry. 278:33465-33473 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m302807200 |
| Popis: | H-Ras and N-Ras become activated both at the plasma membrane and in endomembrane structures such as the Golgi apparatus. This compartmentalized activation is relevant from a signaling standpoint, because effector molecules can become activated differently depending on the region of the cell where Ras proteins are activated. An unsolved question in this new regulatory mechanism is the understanding of how Ras proteins become activated in endomembranes. To approach this problem, we have studied the subcellular distribution and activities of a number of Ras guanosine nucleotide exchange factors. Our results indicate that Ras activation at the plasma membrane and endoplasmic reticulum is an unspecific process that can be achieved by most Ras activators. In contrast, GTP loading of Ras at the Golgi is only induced by members of the Ras guanosine nucleotide releasing protein family. In agreement with these observations, Ras guanosine nucleotide releasing proteins are the only Ras activators showing localization in the Golgi. These results indicate that the compartmentalized activation of effector pathways by Ras proteins depends not only on the specific localization of the GTPases but also in the availability of GDP/GTP exchange factors capable of activating Ras proteins in specific subcellular compartments. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|