Serine/threonine-protein phosphatase 2A 56 kDa regulatory subunit beta isoform is a protein in humans that is encoded by PPP2R5B gene. As the regulatory component of the serine/threonine-protein phosphatase 2A (PP2A) holoenzyme, modulates substrate specificity, subcellular localization, and responsiveness to phosphorylation. The phosphorylated form mediates the interaction between PP2A and AKT1, leading to AKT1 dephosphorylation.