PPM1A is a metal-dependent serine/threonine protein phosphatase that requires Mg2+/Mn2+ ions for catalytic activity and functions as a broad-specificity regulatory enzyme 1. Its primary function involves negative regulation of multiple signaling pathways through targeted dephosphorylation of key proteins. PPM1A negatively regulates TGF-β signaling by dephosphorylating SMAD2 and SMAD3, leading to their dissociation from SMAD4 and nuclear export, thereby terminating TGF-β-mediated responses 23. The enzyme also dephosphorylates AMPK catalytic subunits (PRKAA1/PRKAA2), playing a crucial role in metabolic regulation and autophagy control 4. In disease contexts, PPM1A demonstrates significant clinical relevance across multiple pathologies. Elevated PPM1A expression contributes to osteoarthritis progression through excessive SMAD2 dephosphorylation, while PPM1A inhibition protects against cartilage degeneration 3. The phosphatase also exacerbates blood-brain barrier disruption after subarachnoid hemorrhage through interactions with NDRG2 2. Therapeutically, PPM1A represents a promising drug target, with specific inhibitors showing efficacy in treating osteoarthritis 3, tuberculosis through autophagy activation 5, and potential applications in antidepressant response 6. The enzyme's broad substrate specificity and involvement in multiple disease pathways highlight its importance as a regulatory hub in cellular signaling networks.