POSH, JIP-1, MLK3, MKK7, JNK1, JNK2, NF-κB p65, Rac1, T-bet, and p-cJUN antibodies (Santa Cruz Biotechnology). pSAPK/JNK, p-p38 MAPK, JNK2, cleaved caspase-3, and pSAPK/JNK antibodies (Cell Signaling). Perforin and Eomes antibodies (eBioscience). Granzyme B was from Invitrogen. TNF-α, IFN-γ, and Ki-67 (BD Pharmigen). Rac1 was from Millipore. β-actin was from Sigma. Tat-POSH (NH2-GRKKRRQRRRPPRPRKEDELELRKGEMFLVFER-amide), selleck chemicals Tat-scrambled (NH2-GRKKRRQRRRPPRPDRKLEVFEKEFLRMELGER-amide), and Tat (NH2-GRKKRRQRRRPP-amide) peptides were synthesized by New England Peptides to a purity

of >70 and >90%, respectively. Peptides were used at 20 μM. None of the peptides exhibited nonspecific toxicity

at any concentration tested. Tat and Tat-scrambled gave similar results and were used interchangeably throughout and labeled as Tat-control. SP600125 (Calbiochem) was used at 33 μM. All inhibitors were added 30 min before stimulation and cultures were maintained in constant presence of fresh inhibitor except where indicated otherwise. For IP-FCM and immunoblot experiments, naïve T cells from OT-I Rag−/− mice were stimulated with OVA-Tet plus α-CD28 (1 μg/mL) or 50 ng/mL PMA plus 500 ng/mL ionomycin (Sigma). For all other experiments, OT-I splenocytes were stimulated with 0.2 nM OVA-peptide. click here IL-2 was used at 50 μ/mL. Where indicated, OT-I T cells were labeled with 10 μM CFSE. When required, cells were restimulated with OVA-Tet in the presence of 3 μg/mL Brefeldin A (Sigma) for 6 h. Cells were lysed in buffer containing 10 mM Tris, 1% Triton X-100, 0.5% Igepal CA-630 (Sigma), 150 mM NaCl, 1 mM EDTA, 1 mM EGTA, and freshly added protease and phosphotase inhibitors. Following lysis for 20 min on ice, samples were spun to clear lysates of cellular debris and the cleared supernatant was

used for immunoblot or IP-FCM analysis. Standard IP with Rac1 and GST-PAK were performed as previously described [51]. IP-FCM was performed using α-Rac1, α-JIP-1, and α-POSH CML beads as previously CHIR 99021 described [33-35]. In brief, antibodies were covalently coupled to polystyrene latex beads, then incubated with cell lysates overnight at 4°C, extensively washed in lysis buffer, and stained with the appropriate primary and highly crossabsorbed secondary antibodies (Invitrogen) and analyzed by FCM. Singlet beads were identified on the basis of forward and size scatter. A minimum of 1500 bead events was collected for each experiment and analyzed using FlowJo (TreeStar). Graphs depicting relative secondary analyte were generated by normalizing the geometric MFI of the secondary analyte to the geometric MFI of the primary analyte (to control for potential variations in IP efficiency (loading control)) to Tat-cont.-treated cells.