Fig. 5.

FAM49B controls T cell activation by regulating cytoskeleton remodeling. (A) J.FAM49B cells stably expressing FAM49B or GFP were stimulated with anti-TCR. Cells were lysed at indicated times, Rac1–GTP pull-down assays were carried out using Pak-PBD beads. GTPγS and GDP-loaded lysates were used as controls. Total Rac1, β-actin, FAM49B and active Rac1 were detected by Western blot. (B) The samples in A were stimulated with C305 for times indicated. Phosphorylation of PAK was assessed by immunoblotting. (C) J.FAM49B cells were transduced with virus expressing empty vector (GFP), WT-FAM49B, or FAM49B (R161D) at an MOI of 0.5. Quantification of the F-actin level was assessed by flow cytometry. (D) J.FAM49B cells stably expressing WT-FAM49B, GFP, or FAM49B (R161D) were stimulated with anti-TCR for indicated time. Phosphorylation of PAK and ERK was assessed by immunoblotting.