PP2A-B55-δ Inhibitors

PP2A-B55-δ inhibitors are a class of chemical compounds that specifically target and inhibit the activity of the PP2A holoenzyme containing the B55-δ regulatory subunit. Protein phosphatase 2A (PP2A) is a highly conserved serine/threonine phosphatase involved in the regulation of a wide range of cellular processes, including cell cycle progression, signal transduction, and metabolic control. The PP2A holoenzyme is composed of a catalytic subunit, a scaffolding subunit, and a regulatory subunit that determines substrate specificity and localization. The B55-δ subunit is one of several regulatory subunits in the B55 family, and its presence in the holoenzyme specifically influences the enzyme's role in the dephosphorylation of key proteins involved in mitotic exit and other crucial cellular processes. Inhibitors of PP2A-B55-δ selectively block the activity of this holoenzyme configuration, thus affecting the finely tuned balance of phosphorylation and dephosphorylation in the cell.

The PP2A-B55-δ complex is important in modulating the phosphorylation state of proteins involved in the mitotic spindle and other cellular structures, playing a significant role in cell division and the regulation of mitotic exit. B55-δ, as a regulatory subunit, directs the phosphatase activity of PP2A toward specific substrates, ensuring the proper timing and localization of dephosphorylation events. Inhibition of PP2A-B55-δ disrupts this regulatory function, leading to alterations in the phosphorylation status of its target proteins, which can impact various cellular processes, particularly those related to cell cycle control and structural organization. Understanding how PP2A-B55-δ inhibitors affect these pathways offers deeper insights into the complex regulatory mechanisms that govern cellular function and the role of phosphatases in maintaining cellular homeostasis. This class of inhibitors provides a valuable tool for studying the intricate network of phosphorylation-dependent regulation.