Cells were lysed either in RIPA buffer (Cell Signaling, Danvers, MA, USA) plus 0.2 % SDS and protease inhibitors, or directly in Laemmli buffer (10% SDS), before boiling and loading onto 10–12% SDS-page gels. Immunoblot analysis was performed as previously described (14 (link)). Rabbit monoclonal antibodies anti-RPS6, anti-RPS6-S235/236, anti-Akt-S473, anti-p70S6K-T389, anti-eIF2α-S51, anti-eIF4E-S209, anti-4E-BP1-T37/T46, anti-RSK1/2/3, anti-RSK1 (p90S6K1)-380, anti-RSK1-T573, anti-RSK1-T359/S363 and anti-eIF4B-S422 were all from Cell Signaling. Secondary HRP-conjugated anti-rabbit IgG antibodies were from either Cell Signaling or Pierce/Thermo Fisher Scientific (Rockford, IL, WI). Mouse monoclonal anti-β-actin was purchased from Sigma. Goat polyclonal anti-semaphorin-7A antibody was from R&D Systems. Donkey anti-goat antibody was from Santa Cruz. Immunoreactive bands were visualized with Super Signal West Femto chemiluminescent substrate (Pierce/Thermo Fisher Scientific). Bands were quantified using the FluorChem® Q Imaging System (Alpha Innotech/ProteinSimple, Santa Clara, CA, USA).