TY - JOUR
T1 - Differential interaction of the ras family GTP-binding proteins H-Ras, Rap1A, and R-Ras with the putative effector molecules Raf kinase and Ral-guanine nucleotide exchange factor
AU - Herrmann, C.
AU - Horn, G.
AU - Spaargaren, M.
AU - Wittinghofer, A.
PY - 1996
Y1 - 1996
N2 - The interactions of H-Ras, R-Ras, and Rap1A with the Ras-binding domains (RBD) of the c-Raf kinase and of the Ral guanine nucleotide exchange factor (RGF) was studied biochemically in solution. From deletion cloning the RGF-RBD was defined as a 97-amino acid-long fragment from the C-terminal end of the human RGF, which is an independent folding domain with high stability. Interestingly, whereas H-Ras binds with high affinity (KD = 20 nM) to Raf-RBD and with low affinity (KD = 1 microM) to RGF-RBD, Rap1A shows the opposite behavior. The binding of both RBDs to R-Ras is weak and shows no specificity. The interaction between Rap1A and RGF-RBD shows similar characteristics to the Ras-Raf interaction because it is blocked by mutations in the effector region (D38A) and it inhibits the dissociation of guanine nucleotide, which is the basis for the quantitative measurements in this work. Furthermore, the binding of RGF-RBD inhibits the interaction between Rap1A and Rap-GAP. As long as the cellular localizations of the different proteins and their biological functions are not clarified, these biochemical data seem to indicate that Ral-guanine nucleotide exchange factors is an effector molecule of Rap1A rather than of H-Ras
AB - The interactions of H-Ras, R-Ras, and Rap1A with the Ras-binding domains (RBD) of the c-Raf kinase and of the Ral guanine nucleotide exchange factor (RGF) was studied biochemically in solution. From deletion cloning the RGF-RBD was defined as a 97-amino acid-long fragment from the C-terminal end of the human RGF, which is an independent folding domain with high stability. Interestingly, whereas H-Ras binds with high affinity (KD = 20 nM) to Raf-RBD and with low affinity (KD = 1 microM) to RGF-RBD, Rap1A shows the opposite behavior. The binding of both RBDs to R-Ras is weak and shows no specificity. The interaction between Rap1A and RGF-RBD shows similar characteristics to the Ras-Raf interaction because it is blocked by mutations in the effector region (D38A) and it inhibits the dissociation of guanine nucleotide, which is the basis for the quantitative measurements in this work. Furthermore, the binding of RGF-RBD inhibits the interaction between Rap1A and Rap-GAP. As long as the cellular localizations of the different proteins and their biological functions are not clarified, these biochemical data seem to indicate that Ral-guanine nucleotide exchange factors is an effector molecule of Rap1A rather than of H-Ras
M3 - Article
C2 - 8636102
SN - 0021-9258
VL - 271
SP - 6794
EP - 6800
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 12
ER -