14-3-3 Proteins: insights from genome-wide studies in yeast.

14-3-3 proteins form a family of highly conserved, acidic, dimeric proteins. These proteins have been identified in all eukaryotic species investigated, often in multiple isoforms, up to 13 in the plant Arabidopsis thaliana. Hundreds of proteins, from diverse eukaryotic organisms, implicated in numerous cellular processes, have been identified as binding partners of 14-3-3 proteins. Therefore, the major activity of 14-3-3 proteins seems to be its ability to bind other intracellular proteins. Binding to 14-3-3 proteins may result in a conformational change of the protein required for its full activity or for inhibition of its activity, in interaction between two binding partners or in a different subcellular localization. Most of these interactions take place after phosphorylation of the binding partners. These observations suggest a major role of 14-3-3 proteins in regulatory networks. Here, the information on 14-3-3 proteins gathered from several genome- and proteome-wide studies in the yeast Saccharomyces cerevisiae is reviewed. In particular, the protein kinases responsible for the phosphorylation of 14-3-3 binding partners, phosphorylation of 14-3-3 proteins themselves, the transcriptional regulation of the 14-3-3 genes, and the role of 14-3-3 proteins in transcription are addressed. These large scale studies may help understand the function of 14-3-3 proteins at a cellular level rather than at the level of a single process.