FIG. 3.

Intracellular localization of Ras proteins in immortalized fibroblasts. Cre adenovirus fully converted Rce1^flox/flox into Rce1^Δ/Δ fibroblasts. Fibroblasts were fractionated into cytosolic (S100) and membrane (P100) fractions; Ras proteins were immunoprecipitated and analyzed on Western blots of sodium dodecyl sulfate-polyacrylamide gels with antibody Ab-4. Virtually identical results were observed with independently derived lines of Rce1^flox/flox and Rce1^Δ/Δ fibroblasts (not shown). Also, very similar results were obtained when the experiments were performed with K-Ras-specific antibodies (data not shown).