Hong-Yeoul Ryu
Environmental changes induce many acute and long-term adaptive cellular responses. Mammals have diverse adaptive mechanisms for stress resistance, such as immune responses to pathogens or hormone-mediated homeostatic processes. At the cellular level, acute changes in the local microenvironment, such as changes of pH or temperature, oxidative stress, or nutrient limitation, may induce programmed cell death or trigger adaptive changes that include gene mutation, aneuploidy, changes in gene expression or epigenetic alterations. The small ubiquitin-like modifier (SUMO) protein is a conserved post-translational modifier that regulates a host of proteins in eukaryotic cells and maintains cell homeostasis when the cell encounters endogenous or environmental stress, such as osmotic stress, hypoxia, heat shock, genotoxic stress, and nutrient stress. In response to acute loss of the Ulp2 SUMO-specific protease, yeast become disomic for chromosome I (ChrI) and ChrXII.