The Inactivation Mechanism of Low Molecular Weight Phosphotyrosine-protein Phosphatase by H2O2

Because a physiological concentration of H2O2 produces enzyme inactivation and considering that the activity is restored by reduction with low molecular weight thiols, we suggest that oxidative stress conditions and other processes producing hydrogen peroxide regulate the Low molecular weight phosphotyrosine-protein phosphatase ) in the cell

Anna Caselli; Riccardo Marzocchini; Guido Camici; Giampaolo Manao; Gloriano Moneti; Giuseppe Pieraccini; Giampietro Ramponi

2002

Scholarcy highlights

  • Protein tyrosine phosphorylation in eucaryotes is a key mechanism for cellular control, because it is involved in several processes, such as cellular metabolism, proliferation, differentiation, and oncogenic transformation
  • Because a physiological concentration of H2O2 produces enzyme inactivation and considering that the activity is restored by reduction with low molecular weight thiols, we suggest that oxidative stress conditions and other processes producing hydrogen peroxide regulate the Low molecular weight phosphotyrosine-protein phosphatase) in the cell
  • The activation of tyrosine kinase growth factor receptors transiently enhances cellular protein phosphorylation, which is rapidly reverted by the action of potent cellular PTPs, both membrane-bound and soluble enzymes
  • The high number of PTPs codified in the eucaryotic genome suggests that the regulation of cellular protein phosphorylation levels does not depend exclusively on the regulation of protein-tyrosine kinases, and on the regulation of certain PTPs
  • LMW-PTP has been implicated in the regulation of cell signaling started by the activation of PDGF and insulin receptors
  • The results described in this paper reveal an additional mechanism for the regulation of LMW-PTP activity: hydrogen peroxide, produced during cellular oxidative stress conditions and during mitogenic signaling starting from a number of membrane receptors, inactivates both LMW-PTP isoenzymes at physiological concentration levels
  • We think that our findings on the reversible H2O2 inactivation of Low molecular weight phosphotyrosine-protein phosphatase), an enzyme involved in the regulation of some signaling pathways starting from tyrosine kinase receptors, may contribute to understanding the mechanisms of some ROS cellular actions

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