Constitutively active Fyn bypasses the block of TCR-dependent JNK activation by NSAIDs. (A) Immunoblot analysis of postnuclear supernatants from Jurkat cells stably transfected with empty vector or a construct encoding either F528Fyn or F505Lck. The filters were sequentially probed with anti-Fyn or anti-Lck and antitubulin mAb. Below is an antiphosphotyrosine immunoblot of the 3 lines, subsequently reprobed with antitubulin mAb. (B-C) Immunoblot analysis of postnuclear supernatants from Jurkat cells stably transfected with empty vector or a construct encoding either F528Fyn (B) or F505Lck (C), either nonactivated (0) or activated by CD3 (CD3) ligation for 5 minutes, in the presence or absence of 15 μM sc-560. Each filter was sequentially probed by immunoblot with antiphospho–JNK and then, after stripping, with control antitubulin mAb. The migration of molecular mass markers is shown.