PTPA localized in the Golgi apparatus plays an important role in osteoblast differentiation

Regulatory subunits of protein phosphatase 2A (PP2A) define the substrate and functional specificity of the PP2A holoenzyme within specific organelles. While PP2A regulates osteoblast differentiation, the roles and localization of its regulatory subunits in osteoblasts remain unclear. Here, we identified PTPA, a PP2A regulatory protein, predominantly localized to the Golgi apparatus, closely overlapping with the Golgi marker Giantin. Disruption of the Golgi structure by Brefeldin A caused PTPA to disperse into the cytoplasm. PTPA overexpression inhibited osteoblast differentiation by downregulating key transcriptional regulators. The Golgi-specific localization of PTPA suggests it may influence bone-related protein secretion and maintain Golgi integrity. These findings highlight the critical role of PTPA in osteoblast differentiation and its association with the Golgi apparatus.