Document Detail


A dominant negative RAS-specific guanine nucleotide exchange factor reverses neoplastic phenotype in K-ras transformed mouse fibroblasts.
MedLine Citation:
PMID:  10815806     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Ras proteins are small GTPases playing a pivotal role in cell proliferation and differentiation. Their activation state depends on the competing action of GTPase Activating Proteins (GAP) and Guanine nucleotide Exchange Factors (GEF). A tryptophan residue (Trp1056 in CDC25Mm-GEF), conserved in all ras-specific GEFs identified so far has been previously shown to be essential for GEF activity. Its substitution with glutamic acid results in a catalytically inactive mutant, which is able to efficiently displace wild-type GEF from p21ras and to originate a stable ras/GEF binary complex due to the reduced affinity of the nucleotide-free ras/GEF complex for the incoming nucleotide. We show here that this 'ras-sequestering property' can be utilized to attenuate ras signal transduction pathways in mouse fibroblasts transformed by oncogenic ras. In fact overexpression of the dominant negative GEFW1056E in stable transfected cells strongly reduces intracellular ras-GTP levels in k-ras transformed fibroblasts. Accordingly, the transfected fibroblasts revert to wild-type phenotype on the basis of morphology, cell cycle and anchorage independent growth. The reversion of the transformed phenotype is accompanied by DNA endoreduplication. The possible use of dominant negative ras-specific GEFs as a tool to down-regulate tumor growth is discussed.
Authors:
P Bossù; M Vanoni; V Wanke; M P Cesaroni; F Tropea; G Melillo; C Asti; S Porzio; P Ruggiero; V Di Cioccio; G Maurizi; A Ciabini; L Alberghina
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Oncogene     Volume:  19     ISSN:  0950-9232     ISO Abbreviation:  Oncogene     Publication Date:  2000 Apr 
Date Detail:
Created Date:  2000-06-08     Completed Date:  2000-06-08     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8711562     Medline TA:  Oncogene     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  2147-54     Citation Subset:  IM    
Affiliation:
Centro Ricerche Dompé, L'Aquila, Italy.
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MeSH Terms
Descriptor/Qualifier:
Animals
Carcinogenicity Tests
Cell Division / genetics
Cell Line, Transformed
Cell Transformation, Neoplastic / genetics*
Down-Regulation
Female
Fibroblasts / pathology
Genes, Dominant
Genes, ras*
Guanine Nucleotide Exchange Factors / genetics*,  metabolism
Guanosine Triphosphate / genetics,  metabolism
Mice
Mice, Nude
Mutation, Missense
Signal Transduction
ras Proteins / genetics,  metabolism*
ras-GRF1 / genetics,  metabolism
Chemical
Reg. No./Substance:
0/Guanine Nucleotide Exchange Factors; 0/ras-GRF1; 86-01-1/Guanosine Triphosphate; EC 3.6.5.2/ras Proteins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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