Chapter 8 Role of c-jun N-terminal kinase in apoptosis

Publisher Summary This chapter discusses the role of C-jun N-terminal kinase (JNK) in apoptosis. The chapter observes that JNK activated by many stimuli that induce apoptosis, plays an important role in many types of apoptosis. However, accumulating evidence indicates that the activation of JNK is not linked to cell death types of apoptosis and, in some circumstances, the activation of JNK actually protects cells against apoptosis. Because the major effect of JNK activation is to increase AP-1 activity, it seems that JNK activation is only required for those forms of apoptosis in which de novo protein synthesis is pivotal. For these types of apoptosis, JNK activation needs to induce the expression of some critical factors that are essential for initiating cell death. However, JNK activation is not required in other forms of apoptosis in which de novo protein synthesis is not essential, such as death factors Fas- and TNF-induced apoptosis. Moreover, it was also reported that JNK activation had a protective effect against TNF-induced apoptosis. Therefore, the role of JNK activation in different types of apoptosis can be completely different. Instead of always inducing or accelerating apoptosis, JNK activation may play the opposite role in certain cases.