Figure 5.

Isoform-specific roles of peroxiredoxin (Prx) during redox-based PDGFR signaling. (a) PrxII functions as a negative regulator of PDGF signaling. Upon growth factor stimulation, active PrxII is recruited to the membrane and serves to relieve oxidative inactivation of membrane-associated PTPs by eliminating localized H₂O₂ production within the PDGFR microenvironment. (b) Receptor activation can also induce localized phosphorylation and inactivation of PrxI by PTKs, such as the redox-regulated cytoplasmic Src (c-Src). Deactivation of PrxI reduces the redox-buffering capacity adjacent to the cellular membrane, allowing for transient and localized increases in H₂O₂ for signal transduction. Additionally, increased H₂O₂ concentrations can also inactivate Prx2 by oxidation of its catalytic cysteine to sulfinic acid.