Project Summary
The long-term goal of my research program is to elucidate redox signaling mechanisms underlying disease
initiation and progression and develop therapeutic strategies that target deregulated pathways. In a physiological
context, the reversible oxidation of reactive cysteine residues within proteins elicits a spectrum of structural
alterations that allow cellular oxidants production to be coupled with changes in protein activity and cell function.
Protein tyrosine phosphatases (PTPs) are such proteins whose function is transiently inactivated in response to
regulated and localized rises in hydrogen peroxide (H2O2) in cells. PTPs dephosphorylate and modulate the
activity of protein kinases and other signaling proteins, underscoring the importance of physiological mechanisms
that inhibit specific PTPs through reversible oxidation. While we know that the inactivation of specific PTPs is
essential to regulate phosphorylation-dependent signaling, we have recently shown that the underlying
mechanisms that regulate the oxidation and reduction of PTPs are far more complex than anticipated. Building
on our seminal discoveries on PTP regulation, we have uncovered novel oxidation and reduction mechanisms
that regulate PTP activity in vivo. Based on published and pilot studies, we propose to characterize and further
explore the broad mechanistic and biological impacts of projects in which we show: 1) oxidation relay-mediated
reversible oxidation of PTPs; 2) non-canonical allosteric PTP reduction by cholesterol; and 3) approaches to
leverage our mechanistic insights to develop small molecules that activate specific PTPs and fine-tune
exacerbated phosphorylation-dependent signaling. Based on our productive track record working on the redox
regulation of PTPs, my research program proposes ways to elucidate the underlying mechanism by which PTPs
are turned off in cells and novel means to specifically activate members of this large, understudied, family of
enzymes. PTPs are an untapped resource, and understanding the complexity of their catalytic regulation by
redox mechanisms will generate knowledge and resources with high potential for translation into therapeutic
modalities.