c-Jun c-Fos NFKB NFKB JNK1 AKT IkB Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine PKC LCK LCK Fyn ZAP70 Syk SLP76 LAT CD4 CD28 CD80 CD86 CD45 CD152 MHC CLass II TCR CD3 Actin IL-2 CD28 Signaling in T-Helper Cell