Figure 1.

Redox regulation of PTEN and TCPTP by ROS. (A). PTEN is reversibly oxidized by ROS and forms a disulfide bond between two cysteine residues. The Trx/TrxR/NADPH system is responsible for the reduction of oxidized PTEN. PTEN may undergo hyperoxidation upon exposure to high levels of ROS. (B). TCPTP oxidation into a reversible -SOH is thought to produce a sulfenamide with an adjacent nitrogen atom. The Trx system also plays a key role in reducing oxidized TCPTP. An amount of TCPTP undergoes hyperoxidation into irreversible -SO₂H and -SO₃H.