A response of protein synthesis to temperature shift in the yeast Saccharomyces cerevisiae

When Saccharomyces cerevisiae are subjected to a sudden increase in temperature (22 degrees C to 37 degrees C) they undergo extensive and, in some cases, extreme alterations in their rates of synthesizing individual polypeptides. These changes were monitored by pulse-labeling cells with [35S]methionine and separating the total soluble proteins by two-dimensional gel electrophoresis. Incorporation of 35S into individual proteins was measured by a computer-coupled autoradiogram-scanning method. The rates of synthesis of most proteins are transiently changed; 10-fold or greater induction or respression is common. This temperature response has also been studied in a mutant strain that is temperature sensitive for the nucleus-to-cytoplasm transport of RNA. In this mutant, not only the induction, but also a part of the repression in response to temperature upshift is largely inhibited. Conceivable mechanisms are discussed.