Protein metamorphosis in adaptation to persistent stress in S. cerevisiae

Temperature is a variable component of the environment and all organisms must deal with or adapt to temperature change. Acute temperature change activates cellular stress response resulting in refolding or removal of damaged proteins. However, how organisms adapt to long-term temperature change remains largely unexplored. Here we report that budding yeast responds to long-term high temperature challenge by switching from chaperone-induction to the reduction of temperature sensitive proteins and re-localizing a portion of its proteome. Surprisingly, we also find many proteins adopt an alternative conformation. Using Fet3p as an example, we find that the temperature-dependent conformational difference is accompanied by distinct thermostability, subcellular localization, and importantly, cellular functions. We postulate that in addition to known mechanisms of adaptation, alternative protein folding allows some polypeptides to acquire new biophysical properties and functions when environmental change endures. The purpose of this sequence data is to examine any mutational differences that may have occured during stress adaptation.