MAPK8 and infection: The JNK signaling pathway can be activated by various stimuli, including intracellular stress signals (e.g., oxidative stress, DNA damage and osmotic stress), intercellular mediators (e.g., growth factors and cytokines), and extracellular stimuli (e.g., pathogen infection and inflammatory responses), which activate JNK through a cascade involving upstream kinases such as ASK1/MEKK1 and MKK4/MKK7.