Involvement of Prohibitin Upregulation in Abrin-Triggered Apoptosis

Figure 5

A model of abrin (ABR)-triggered apoptosis. ABR-induced apoptosis may occur through at least 3 pathways: first, inhibition of protein synthesis by its N-glycosidase activity; second, modulation of the function of mitochondria by specific interaction with antioxidant protein-1 (AOP-1); and third, interference with the transcription regulated by prohibitin (PHB). Repression of prohibitin attenuates ABR-triggered apoptosis via preventing the expression of BAX, cleaved-caspase 3, and cleaved-poly(ADP-ribose) polymerase (PARP). Once PHB is upregulated by ABR through the JNK/SAPK signaling pathway, the expression of proapoptotic gene Bax is turned on through the nuclear translocation and p53 interaction of PHB, by which activates the caspase cascade, and finally, apoptosis occurs.