PPP2R5D also known as PP2A-B56-δ, B56δ, B56delta is a member of the phosphatase 2A regulatory subunit B family. PPP2R5D plays a crucial role in various cellular processes, including cell growth, division, and apoptosis. PPP2R5D modulates PP2A holoenzyme activity through a trimeric complex composed of regulatory, variable, and catalytic subunits. PPP2R5D specifically influences substrate specificity and cellular localization, impacting target protein dephosphorylation in critical signaling pathways. PPP2R5D interactions with other subunits form distinct PP2A complexes targeting specific substrates, maintaining cellular homeostasis and responding to stress signals. PPP2R5D regulates diverse cellular functions, highlighting significance in normal physiology and disease states, including cancer, where phosphatase activity dysregulation can lead to aberrant signaling and tumor progression.