Its activation and signal transduction process usually involves the following key steps: (1) Signal stimulation: Activation of the JNK signaling pathway can be triggered by a variety of intracellular stimuli (e.g., oxidative stress, DNA damage, and osmotic stress), intercellular stimuli (e.g., growth factors and cytokines), and extracellular stimuli (e.g., pathogen infection and inflammatory responses). Here, MAPK8 is linked to infection.