Eukaryotic stress response involves changes in transcription, translation, and
proteostasis. Some changes are similar across many stress responses. Stressors such as
misfolded proteins, oxidative stress, viral RNAs, heme deficiency, heat shock, amino
acid shortage, and others activate the integrated stress response (ISR) kinases PERK,
PKR, HRI, and GCN2; they phosphorylate eIF2α inducing global inhibition of
translation. Some stresses, e.g. oxidative and osmotic can activate several kinases.
Transcriptional response to stress involves the suppression of genes functioning in
energy-consuming processes such as protein biosynthesis and activation of genes that
mitigate damage caused by stress. Many stresses interfere with the synthesis and
folding of proteins. When unfolded protein level exceeds folding and clearance
capacity of the cell, the unfolded protein response is triggered, which increases that
capacity by producing more chaperones and proteases. Autophagy is another common
response to stress that helps to cleanse the cell of aggregated proteins and dysfunctional
organelles and replenish the supply of biosynthetic precursors and energy. There are
also responses specific to heat, cold, osmotic, pH, oxidative, and mitochondrial stress.
They involve activation of programs that mediate adjustment to specific stress.
Keywords: Autophagy, Cold stress, Endoplasmic reticulum stress, General stress
response, Heat stress, Integrated stress response, Mitochondrial stress, Osmotic
stress, Oxidative stress, PH stress, Unfolded protein response.
