title: Differences on the inhibitory specificities of H-Ras, K-Ras, and N-Ras (N17) dominant negative mutants are related to their membrane microlocalization.
abstract: Ras GTPases include the isoforms H-Ras, K-Ras, and N-Ras. Despite their great biochemical and biological similarities, evidence is mounting suggesting that Ras proteins may not be functionally redundant. A widespread strategy for studying small GTPases is the utilization of dominant inhibitory mutants that specifically block the activation of their respective wild-type proteins. As such, H-Ras N17 has proved to be extremely valuable as a tool to probe Ras functions. However, a comparative study on the inhibitory specificities of H-, K-, and N-Ras N17 mutants has not been approached thus far. Herein, we demonstrate that H-, K-, and N-Ras N17 mutants exhibit markedly distinct inhibitory effects toward H-, K-, and N-Ras. H-Ras N17 can effectively inhibit the activation of all three isoforms. K-Ras N17 completely blocks the activation of K-Ras and is only slightly inhibitory on H-Ras. N-Ras N17 can mainly inhibit N-Ras activation. In light of the recent data on the compartmentalization of H-Ras and K-Ras in the plasma membrane, here we present for the first time a description of N-Ras cellular microlocalization. Overall, our results on Ras N17 mutants specificities exhibit a marked correlation with the localization of the Ras isoforms to distinct membrane microdomains.
authors.affiliation: Departamentos de Biología Molecular, Universidad de Cantabria, Santander 39011, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Matallanas
authors.forename: Imanol
authors.initials: I
authors.lastname: Arozarena
authors.forename: Maria T
authors.initials: MT
authors.lastname: Berciano
authors.forename: David S
authors.initials: DS
authors.lastname: Aaronson
authors.forename: Angel
authors.initials: A
authors.lastname: Pellicer
authors.forename: Miguel
authors.initials: M
authors.lastname: Lafarga
authors.forename: Piero
authors.initials: P
authors.lastname: Crespo
mesh_terms: D016475:3T3 Cells; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D004285:Dogs; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009154:Mutation; D017434:Protein Structure, Tertiary / Q000235:genetics; D018631:ras Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D018631:ras Proteins