title: A constitutive effector region on the C-terminal side of switch I of the Ras protein.
abstract: The "switch I" region (Asp30-Asp38) of the Ras protein takes remarkably different conformations between the GDP- and GTP-bound forms and coincides with the so-called "effector region." As for a region on the C-terminal side of switch I, the V45E and G48C mutants of Ras failed to promote neurite outgrowth of PC12 cells (Fujita-Yoshigaki, J., Shirouzu, M., Koide, H., Nishimura, S., and Yokoyama, S. (1991) FEBS Lett. 294, 187-190). In the present study, we performed alanine-scanning mutagenesis within the region Lys42-Ile55 of Ras and found that the K42A, I46A, G48A, E49A, and L53A mutations significantly reduced the neurite-inducing activity. This is an effector region by definition, but its conformation is known to be unaffected by GDP-->GTP exchange. So, this region is referred to as a "constitutive" effector (Ec) region, distinguished from switch I, a "switch" effector (Es) region. The Ec region mutants exhibiting no neurite-inducing activity were found to be correlatably unable to activate mitogen-activated protein (MAP) kinase in PC12 cells. Therefore, the Ec region is essential for the MAP kinase activation in PC12 cells, whereas mutations in this region only negligibly affect the binding of Ras to Raf-1 (Shirouzu, M., Koide, H., Fujita-Yoshigaki, J., Oshio, H., Toyama, Y., Yamasaki, K., Fuhrman, S. A., Villafranca, E., Kaziro, Y., and Yokoyama, S. (1994) Oncogene 9, 2153-2157).
authors.affiliation: Department of Biophysics and Biochemistry, School of Science, University of Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Fujita-Yoshigaki
authors.forename: M
authors.initials: M
authors.lastname: Shirouzu
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
authors.forename: S
authors.initials: S
authors.lastname: Hattori
authors.forename: S
authors.initials: S
authors.lastname: Furuyama
authors.forename: S
authors.initials: S
authors.lastname: Nishimura
authors.forename: S
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D004252:DNA Mutational Analysis; D004789:Enzyme Activation; D020558:GTP Phosphohydrolases / Q000378:metabolism; D020690:GTPase-Activating Proteins; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D016297:Mutagenesis, Site-Directed; D016501:Neurites; D027384:Oncogene Proteins v-raf; D016716:PC12 Cells; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism; D051381:Rats; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics; D020703:ras GTPase-Activating Proteins; D018631:ras Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D020690:GTPase-Activating Proteins; D011506:Proteins; D015682:Retroviridae Proteins, Oncogenic; D020703:ras GTPase-Activating Proteins; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D027384:Oncogene Proteins v-raf; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D020558:GTP Phosphohydrolases; D018631:ras Proteins