Inactivation of Icmt inhibits transformation by oncogenic K-Ras and B-Raf
J. Clin. Invest. Martin O. Bergo, et al. 113:539 doi:10.1172/JCI18829 [Go to this article.]

Figure 5
Mislocalization and increased steady-state levels of K-Ras in Icmt-deficient fibroblasts. (a) Confocal micrographs of spontaneously immortalized Icmt^+/+ and Icmt^–/– fibroblasts that had been transfected with a GFP–K-Ras fusion construct. (b) Distribution of Ras proteins in the membrane (P100) and cytosolic (S100) fractions of K-Ras-Icmt^flx/flx fibroblasts and the derivative K-Ras-Icmt^Δ/Δ fibroblasts. The Ras proteins were immunoprecipitated from 1,000 μg of the indicated cell fractions with a pan-Ras–specific antibody, and a Western blot was performed with a K-Ras–specific antibody. (c) GTP-bound Ras proteins in K-Ras-Icmt^flx/flx fibroblasts and derivative K-Ras-Icmt^Δ/Δ fibroblasts. GTP-bound Ras proteins were precipitated from 1 × 10⁶ K-Ras-Icmt^flx/flx and K-Ras-Icmt^Δ/Δ cells with the Ras-binding domain of Raf (Ras Activation Kit; Upstate Biotechnology Inc.), and a Western blot was performed with a pan-Ras antibody. (d) Northern blot of total RNA from K-Ras-Icmt^flx/flx and K-Ras-Icmt^Δ/Δ fibroblasts, hybridized with a mouse Kras2 cDNA probe. That probe detects a longer mouse Kras2 transcript (upper panel) and a shorter human activated K-Ras transcript (middle panel). The blot was stripped and hybridized with a Gapdh cDNA probe (lower panel). IP, immunoprecipitation; NB, Northern blot.