... kinases, including src and fyn, Bruton’s tyro-sine kinase (btk) and syk in an in vitro kinase assayusing S6K1 and 2 as substrates. As shown in Fig. 1C,all tested tyrosine kinases, in particular ... 2023Ribosomal protein S6 kinase (S6K) is a serine ⁄ threon-ine kinase belonging to the family of AGC kinases,which includes protein kinase A (PKA), protein kinaseB (PKB ⁄ Akt), protein kinase C (PKCs), ... nutrients within a cell [5]. The activation of S6Kis a multistep phosphorylation event, involving severalser ⁄ thr kinases. Initially, a series of serines and threo-nines in the C-terminal autoinhibitory...