Figure 4. Cellular stress responses.

Exposure to stress stimuli (e.g., bacteria, viruses, radiation, and environmental toxins) induces cytoprotective responses that restore cellular homeostasis. Oxidative stress (yellow) is an example of stress that is a result of an oxidant–antioxidant imbalance in cells. The stress responses are categorized into heat shock response (green), UPR (blue), and DDR (pink). The major proteins or molecules responsible for mediating these stresses and stress responses and that play a pivotal role in innate immune signaling are enumerated.