title: Reactivation of oxidized PTP1B and PTEN by thioredoxin 1.
abstract: The transient inactivation of protein phosphatases contributes to the efficiency and temporal control of kinase-dependent signal transduction. In particular, members of the protein tyrosine phosphatase family are known to undergo reversible oxidation of their active site cysteine. The thiol oxidation step requires activation of colocalized NADPH oxidases and is mediated by locally produced reactive oxygen species, in particular H2 O2 . How oxidized phosphatases are returned to the reduced active state is less well studied. Both major thiol reductive systems, the thioredoxin and the glutathione systems, have been implicated in the reactivation of phosphatases. Here, we show that the protein tyrosine phosphatase PTP1B and the dual-specificity phosphatase PTEN are preferentially reactivated by the thioredoxin system. We show that inducible depletion of thioredoxin 1(TRX1) slows PTEN reactivation in intact living cells. Finally, using a mechanism-based trapping approach, we demonstrate direct thiol disulphide exchange between the active sites of thioredoxin and either phosphatase. The application of thioredoxin trapping mutants represents a complementary approach to direct assays of PTP oxidation in elucidating the significance of redox regulation of PTP function in the control of cell signaling.
  TRX1 physically interacts with PTP1B by anti tag coimmunoprecipitation (1, 2).
authors: Cold Spring Harbor Laboratory, NY, USA.
authors: Ulla
authors: U
authors: Schwertassek
authors: Aftabul
authors: A
authors: Haque
authors: Navasona
authors: N
authors: Krishnan
authors: Romy
authors: R
authors: Greiner
authors: Lars
authors: L
authors: Weingarten
authors: Tobias P
authors: TP
authors: Dick
authors: Nicholas K
authors: NK
authors: Tonks
mesh_terms: D020134:Catalytic Domain; D004220:Disulfides / Q000737:chemistry; D004789:Enzyme Activation; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D007328:Insulin / Q000502:physiology; D010084:Oxidation-Reduction; D051059:PTEN Phosphohydrolase / Q000737:chemistry* / Q000502:physiology; D011485:Protein Binding; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000737:chemistry* / Q000502:physiology; D013879:Thioredoxins / Q000737:chemistry* / Q000502:physiology
chemical_list: D004220:Disulfides; D007328:Insulin; D013879:Thioredoxins; C516607:PTPN1 protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: insulin signaling; phosphatase; reactive oxygen species; redox regulation; substrate trapping; thioredoxin 1