Cell growth and survival are constantly promoted and modulated by a variety of extracellular stimuli. Modules of sequentially activating protein kinases serve as important routes for the intracellular transmission of signals from diverse stimuli to nucleus. The Raf signaling involving Mitogen-Activated Protein (MAP) kinases is a key element of mitogenic stimulation. The c-Jun N-terminal kinases (JNKs) are activated in cells in response to cytokines, stress or proapoptotic stimuli, indicating that this signaling pathway may contribute to inflammatory and cell death phenomena. Cross-talk between different MAP kinase signaling pathways determines cellular responses in stress, apoptosis and normal physiological processes.