S-Glutathionylation: Indicator of Cell Stress and Regulator of the Unfolded Protein Response

Regulation of PDI by its specific S-glutathionylation. A. PDI is a member of the thioredoxin superfamily of small thiol-rich proteins. The protein sequence of PDI includes seven cysteine residues (highlighted in red). Basic amino acids that flank cysteine residues (green) may act to lower the pKa of the thiol group, making the relevant Cys more likely to be susceptible to S-glutathionylation. B. A cartoon structure of the domains in PDI shows a single cysteine in the N-terminal domain, four in the catalytic domains, and two in the b’ domain.