Figure 2. PAD2 is required for joint citrullination.

Protein lysates from the ankles of 4–5 month old TNF⁺PAD2^+/+ and TNF⁺PAD2^−/− mice were subjected to western blot to detect citrullinated proteins and gel electrophoresis to detect total protein. A. Representative blot (left) and gel (right). B. The density of the entire lanes was determined and citrullinated protein signal was normalized to total protein signal. Average and SEM are graphed for the entire lane (TNF⁺PAD2^+/+ n=9, TNF⁺PAD2^−/− n=8, *p<0.05). Ankle lysates from PAD2^+/+ and PAD2^−/− littermates were similarly assessed. C. Representative blot (left) and gel (right). D. Graph with average and SEM (PAD2^+/+ n=4, PAD2^−/− n=5, **p<0.01).