S6K1 is a kinase for ribosomal protein S6 (rpS6) and its activation by S6K1 is crucial for mRNA translation. Furthermore, a phosphorylated form of 4E-BP1 releases eIF4E from the inactive eIF4E•4E-BP1 complex, allowing the formation of the active eIF4G•eIF4E complex to participate in translation initiation [8].