Heat/Stress Responses

All cells from simple bacteria to highly differentiated animal cells maintain specialized mechanisms to monitor and respond to changes in their local environments. Unfavorable circumstances that threaten cellular homeostasis will elicit one or more stress response programs in an effort to preserve viability of the organism. The many forms of cellular stress include temperature variation, exposure to toxic compounds, oxidative and reductive stress, ionizing radiation, hypoxia, aging, mechanical injury, and the invasion of pathogens. Mounting the correct response can insure cell survival or initiate an apoptotic program depending on the severity of the stress. Stress responses are also activated in numerous disease states and deficient responses are etiological for afflictions including Parkinson's and Alzheimer's diseases. More recently, stress-regulated genes were intimately linked to aging and shown to be required for the extension of life in model organisms. As a general rule, stress responses remodel relevant cellular pathways to counteract specific effects of the insult.