Differences on the inhibitory specificities of H-Ras, K-Ras, and N-Ras (N17) dominant negative mutants are related to their membrane microlocalization.
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.
Matallanas
David
D
Departamentos de Biología Molecular, Universidad de Cantabria, Santander 39011, Spain.
Arozarena
Imanol
I
Berciano
Maria T
MT
Aaronson
David S
DS
Pellicer
Angel
A
Lafarga
Miguel
M
Crespo
Piero
P
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
D007527:Isoenzymes; D018631:ras Proteins