Fig. 2.

Effects of p13 function at the mitochondrial level: a working model. p13 is inserted in the inner mitochondrial membrane (IM) and generates an inward K⁺ current in mitochondria. This effect may result either from the direct channel-forming ability of p13 (upper part of the scheme) or by its influence on cellular K⁺ channels located in the mitochondria (lower part of the scheme). This effect leads to IM depolarization that in turn increases the activity of the electron transport chain (ETC) which, by increasing H⁺ extrusion, dampens the depolarizing effect of p13. Furthermore, increased ETC activity results in increased ROS production which, along with membrane depolarization, may lower the opening threshold of the permeability transition pore (PTP).