Dephosphorylation of AKT by PP2A

When CTLA4 is engaged by B7 molecules, PP2A disassociates from CTLA4 in a phosphorylation dependent manner. Released PP2A acts downstream of early TCR and CD28 signaling, by inhibition of the PKB/Akt pathway.当CTLA4被B7分子激活时，PP2A以磷酸化依赖的方式从CTLA4上解离。释放的PP2A在早期TCR和CD28信号传导下游发挥作用，通过抑制PKB/Akt通路来实现。