Tumor necrosis factor (TNF) is a proinflammatory cytokine that plays a critical role in diverse cellular events, including cell proliferation, differentiation and apoptosis. TNF is also involved in many types of diseases. In recent years, the molecular mechanisms of TNF functions have been intensively investigated. Studies from many laboratories have demonstrated that the TNF-mediated diverse biological responses are achieved through activating multiple signal- ing pathways. Especially the activation of transcription factors NF-κB and AP-1 plays a critical role in mediating these cellular responses. Several proteins, including FADD, the death domain kinase RIP and the TNF receptor associated factor TRAF2 have been identified as the key effectors of TNF signaling. Recently, we found that the effector mol- ecules of TNF signaling, such as RIP and TRAF2, are also involved in other cellular responses. These finding suggests that RIP and TRAF2 serve a broader role than as just an effector of TNF signaling. Tumor necrosis factor (TNF) is a critical role in diverse cellular events, including cell proliferation, differentiation and apoptosis. TNF is also involved in many types of diseases. intensively investigated. The experiments from many laboratories have demonstrated that the TNF-mediated diverse biological responses are achieved through activating multiple signal- ing pathways. Especially the activation of transcription factors NF-κB and AP-1 plays a critical role in mediating these cellular responses. Several proteins, including FADD, the death domain kinase RIP and the TNF receptor associated factor TRAF2 have been identified as the key effectors of TNF signaling. Recently, we found that the effector mol- ecules of TNF signaling, such as RIP and TRAF2, are also means in other cellular responses. These measures suggests that that RIP and TRAF2 serve a broader role than as just an e ffector of TNF signaling.