Figure 7. Oxidation of individual cysteines in p38.

Plasmids expressing p38 with a carboxy-terminal epitope tag were constructed that expressed otherwise normal p38 (WT), a mutant lacking all four cysteines (4CS), or mutants that contain only one cysteine residue added back to the 4CS mutant (C39, C119, C162, and C211). The encoded proteins were expressed in HeLa cells that were treated with vehicle or with 100 µM PGJ2 for one hour (black bars), and subjected to PROP. Panel A. Oxidation of each mutant protein was determined using anti-p38 immunoblotting. Oxidized fractions are normalized to expression of each mutant protein and oxidation of endogenous p38 in each culture. The proportion of each mutant oxidized is presented relative to the amount of WT p38 oxidation in the PGJ2 treated sample. The data are the average of three completely independent experiments. Panel B. Location of cysteine residues within the p38 protein. Cysteine residues C119 and C162 are located near the surface of the protein, while C39 and C211 are buried within the protein. Structure from PDB, reference ID 1WFC.