Impaired signaling in Rras^−/− BM-DCs. (A) Rras^+/+ BM-DCs were exposed to LPS (1 μg/mL) for the indicated duration, and the levels of GTP-bound R-Ras were measured by an affinity pull-down assay using GST-RalGDS-RBD as a probe. The total levels of R-Ras in the corresponding lysates were detected using an anti–R-Ras specific antibody. Similar experiments were performed for Rap1 and Ras using GST-RalGDS-RBD and GST-Raf-RBD as probes, respectively. (B-C) BM-DCs were treated with LPS (1 μg/mL) for the indicated duration, and total cell lysates were prepared. Western blotting analysis was carried out using the indicated antibodies. Similar results were obtained from 2 additional experiments.