- Interactions: In the brain, SERT has been shown to form a complex with protein phosphatase 2A (PP2A) (Bauman et al. 2000, J. Neurosci. 20, 7571-80). . This interaction appears to regulate the trafficking of the transporter from or to the cell membrane as inhibitors of PP2A as well as activators of PKC disrupt the SERT-PP2A complex and induce down-regulation of transporter activity. In vitro, SERT has been shown to interact with the molecular chaperones calnexin, calreticulin, and immunoglobulin heavy chain binding protein (Bip) (Tate et al. 1999, JBC 274, 17551-8). SERT may also interact with the PDZ domain-containing protein PICK1 ((Torres et al, 2001, Neuron 30, 121-34).