Exploring the dynamics of the yeast proteome by means of 2-DE.

In this study we combined pulse chase experiments and 2-DE in order to investigate how newly synthesized proteins are processed or modified to yield a functional yeast proteome. This approach allowed us to follow the fate of 560 native yeast proteins from the time they were synthesized up to several hours later. Among these, 81 were observed to vary during the chase, either increasing or decreasing. In addition, 60 were found to be modified immediately after their synthesis. Taking advantage of protein identifications, we characterized a wide variety of post-translational events responsible for these changes, such as protein turnover, protein maturation and different types of PTMs. These events operate over very different time scales, ranging from the brief period required for co-translational modifications to one generation time or more. In light of these results, the functional proteome of exponentially growing cells appears to be the product of a permanent remodelling process that modifies native proteins far beyond the time they have been synthesized. This study also allowed us to obtain information on the half-lives of 260 abundant yeast proteins.