RPS6KB1 and neoplasm: Pulsatile shear stress activates several signaling pathways including the PI3K/Akt pathway [22]; in tumor cells, phosphorylated Akt can activate the 70-kDa ribosomal protein S6 kinase (p70-S6K), which may phosphorylate PDCD4 for ubiquitin binding [18], [19].