Characterization of Ras effector mutant interactions with the NF1-GAP related domain

The GTPase activating proteins Ras GAP and the neurofibromatosis-type 1 (NF1) gene product have been implicated as both potential mediators and regulators of the mitogenic effects of the ras proteins. In this study, the interactions of selected Ras effector mutants with the NF1-GAP related domain (NF1-GRD) were investigated. The NF1-GRD was unable to stimulate the GTPase of Ras[Asn33], Ras[Ser35] or Ras[Asn38], all transformation defective mutants. Each of these mutants had reduced but detectable binding to the NF1-GRD (apparent K D of 9 μM, 4 μM and 2 μM respectively, vs 0.5 μM for normal Ha-ras)