Emerging Roles of B56 Phosphorylation and Binding Motif in PP2A-B56 Holoenzyme Biological Function

Abstract

Protein serine/threonine phosphatase 2A (PP2A) regulates diverse cellular processes via the formation of ~100 heterotrimeric holoenzymes. However, a scarcity of knowledge on substrate recognition by various PP2A holoenzymes has greatly prevented the deciphering of PP2A function in phosphorylation-mediated signaling in eukaryotes. The review summarized the contribution of B56 phosphorylation to PP2A-B56 function and proposed strategies for intervening B56 phosphorylation to treat diseases associated with PP2A-B56 dysfunction; it especially analyzed recent advancements in LxxIxEx B56-binding motifs that provide the molecular details of PP2A-B56 binding specificity and, on this basis, explored the emerging role of PP2A-B56 in the mitosis process, virus attack, and cancer development through LxxIxE motif-mediated PP2A-B56 targeting. This review provides theoretical support for discriminatingly targeting specific PP2A holoenzymes to guide PP2A activity against specific pathogenic drivers.