Phosphatase 2A is involved in Adherens Junction (AJ) Regulation in Endothelial Cells

Abstract

We have previously shown that Ser/Thr phosphatase 2A (PP2A) is important for endothelial cell (EC) barrier integrity preservation. To further define the functional role of PP2A in EC barrier we examined the role of PP2A in the regulation of EC AJs. EC immunofluorescence staining revealed the presence of Bα subunit in the AJs area. Moreover specific interaction between PP2AB and AJs proteins was detected by pull down assay. Inhibition of PP2A negatively affected the EC function, in concert with the decreased expression of VE‐cadherin, and β‐catenin in the AJs and inreased β‐catenin phosphorylation. The depletion of Bα (regulatory) PP2A subunit led to the translocation of AJs proteins from the cell junctions to the cytoplasm in parallel with β‐catenin phosphorylation and F‐actin remodeling, suggesting a regulatory role of PP2A in EC barrier function and cytoskeletal integrity. The effect of Bα depletion was further enhanced by thrombin treatment. Collectively, these data strongly suggest that PP2ABα has a functional role in AJs regulation via the dephosphorylation of β‐catenin. These results also support a critical role of Bα plays in the barrier‐protective function of PP2A.MLOG7307