*2.4. E*ff*ecst of PADI2 Knockout on the Protein Expression of Caspases*

We further investigated the effects of PADI2 knockout on the activation of different caspases. In the macrophages stimulated with LPS, we found that the protein levels of the cleaved caspase-3, but not those of the intact caspase-3, were decreased in the PADI2 knockout group compared with in the controls. Among the initiator caspases [13], we found that the protein levels of the cleaved caspase-2 and the cleaved caspase-9, but not those of the intact caspase-2 and the intact caspase-9, were also significantly decreased in the PADI2 knockout group compared with in the controls (Figure 4). In contrast, the protein levels of the cleaved caspase-8, but not those of the intact caspase-8, were significantly elevated in the PADI2 knockout group compared with in the controls.

**Figure 4.** Effects of PADI2 knockout on the relative expression levels of the activated caspase-3, -2, -8, and -9. In the differentiated macrophages stimulated with LPS, the protein expression levels of the intact caspases and the cleaved caspases were performed by Western blotting in the PADI2 knockout group and the control group. The relative protein expression was defined as the ratio of intact caspases or cleaved caspases to the actin band intensity: (**A**) caspase-3; (**B**) caspase-2; (**C**) caspase-8; (**D**) caspase-9.
