Identification of neurofibromin mutants that exhibit allele specificity or increased Ras affinity resulting in suppression of activated ras alleles.
Identification of neurofibromin mutants that exhibit allele specificity or increased Ras affinity resulting in suppression of activated ras alleles.
复制标题
鉴定表现出等位基因特异性或 Ras 亲和力增加的神经纤维蛋白突变体，从而抑制激活的 ras 等位基因。
DOI：
10.1128/mcb.16.5.2496
复制
发表时间：
1996
影响因子：
5.3
通讯作者：
Tamanoi,F
中科院分区：
文献类型：
--
作者：
Morcos,P;Thapar,N;Tusneem,N;Stacey,D;Tamanoi,F
Neurofibromin plays a critical role in the downregulation of Ras proteins in neurons and Schwann cells. Thus, the ability of neurofibromin to interact with Ras is crucial for its function, as mutations in NF1 that abolish this interaction fail to maintain function. To investigate the neurofibromin-Ras interaction in a systematic manner, we have carried out a yeast two-hybrid screen using a mutant of H-ras, H-rasD92K, defective for interaction with the GTPase-activated protein-related domain (GRD) of NF1. Two screens of a randomly mutagenized NF1-GRD library led to the identification of seven novel NF1 mutants. Characterization of the NF1-GRD mutants revealed that one class of mutants are allele specific for H-rasD92K. These mutants exhibit increased affinity for H-rasD92Kand significantly reduced affinity for wild-type H-ras protein. Furthermore, they do not interact with another H-ras mutant defective for interaction with GTPase-activating proteins. Another class of mutants are high-affinity mutants which exhibit dramatically increased affinity for both wild-type and mutant forms of Ras. They also exhibit a striking ability to suppress the heat shock sensitive traits of activated RAS2G19Vin yeast cells. Five mutations cluster within a region encompassing residues 1391 to 1436 (region II). Three NF1 patient mutations have previously been identified in this region. Two mutations that we identified occur in a region encompassing residues 1262 to 1276 (region I). Combining high-affinity mutations from both regions results in even greater affinity for Ras. These results demonstrate that two distinct regions of NF1-GRD are involved in the Ras interaction and that single amino acid changes can affect NF1’s affinity for Ras.
