Figure 9.

Cell swelling and p38 MAPK signaling. (a) Photosensitizer activity in the plasma membrane increases the permeability of the membrane, which causes the intake of calcium ions by the cell. The excess intake of the calcium ion causes the cytoplasmic content to be in the hypertonic state, which induces the absorption of water into the cell, thus leading to swelling of the cell and rupture of the cell. (b) p38 MAPK signaling initiates with activation of Fas receptor and formation of death-inducing signaling complex (DISC) complex. p38 MAPK induces the phosphorylation of Bcl-2 and BCL-xl, which are linked to the inhibition of apoptosis, and it has been found that p38 MAPK also increases the BAX expression. Deactivation of Bcl-2 and Bcl-xl and enhancement of the expression in BAX change the permeability of the mitochondrial outer membrane, which leads to activation of caspase-9 and apoptosis via the intrinsic pathway.