The catalytic domain of the neurofibromatosis type 1 gene product stimulates ras GTPase and complements ira mutants of S. cerevisiae.
Sequencing of the neurofibromatosis gene (NF1) revealed a striking similarity among NF1, yeast IRA proteins, and mammalian GAP (GTPase-activating protein). Using both genetic and biochemical assays, we demonstrate that this homology domain of the NF1 protein interacts with ras proteins. First, expression of this NF1 domain suppressed the heat shock-sensitive phenotype of yeast ira1 and ira2 mutants. Second, this NF1 domain, after purification as a glutathione S-transferase (GST) fusion protein, strongly stimulated the GTPase activity of yeast RAS2 and human H-ras proteins. The GST-NF1 protein, however, did not stimulate the GTPase activity of oncogenic mutant ras proteins, H-rasVal-12 and yeast RAS2Val-19 mutants, or a yeast RAS2 effector mutant. These results establish that this NF1 domain has ras GAP activity similar to that found with IRA2 protein and mammalian GAP, and therefore may also regulate ras function in vivo.
Xu
G F
GF
Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City 84132.
Lin
B
B
Tanaka
K
K
Dunn
D
D
Wood
D
D
Gesteland
R
R
White
R
R
Weiss
R
R
Tamanoi
F
F
D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics; D020690:GTPase-Activating Proteins; D005800:Genes, Fungal; D011905:Genes, ras; D006801:Humans; D009456:Neurofibromatosis 1 / Q000235:genetics*; D025542:Neurofibromin 1; D010957:Plasmids; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D012689:Sequence Homology, Nucleic Acid; D018631:ras Proteins
D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; C064960:IRA2 protein, S cerevisiae; D025542:Neurofibromin 1; D011506:Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; C489015:RAS2 protein, S cerevisiae; D018631:ras Proteins