Understanding Cellular Networks
The model organism S. cerevisiae fueled some of the most important advances in biology and helped scientists understand pivotal concepts in areas spanning signal transduction and DNA repair, cancer, neurodegenerative and cardiovascular pathology, and cholesterol metabolism.
An effective way to gain insight into the regulation of biochemical processes is by exploring protein-protein interactions. Researchers estimate that the total number of interactions in S. cerevisiae ranges between 10,000 and 40,000. While many methods examine protein-protein interactions in vitro, the extent to which such interactions represent an accurate reflection of the in vivo cellular context emerges as an important question.
Stephen Michnick, Ph.D., professor of biochemistry at the University of Montreal and the Canada Research Chair in Integrative Genomics, presented work at the Cold Spring Harbor venue that he performed together with several collaborators to characterize the S. cerevisiae protein interaction network in vivo. The team took advantage of a protein fragment complementation assay. Two proteins of interest, each fused to complementary fragments of a reporter protein, are brought together and reconstitute the reporter activity if an interaction is established between them.
A genome-wide screen of protein-protein interactions identified 2,770 interactions among 1,124 endogenously expressed proteins and established a protein topology map at 8 nm resolution that promises to provide a valuable framework for future studies. A comparison with previous reports revealed that most interactions unveiled by this survey were previously unknown, pointing toward yet unexplored features of the yeast protein interactome.
“The key is to utilize these facts because we now can study interactions in living cells, and we can manipulate live cells with drugs and changes in nutrients. We can ask how the network reorganizes itself and what these changes mean? We can do new things that we have not been able to do with other approaches and learn about the dynamics of the interactome,” said Dr. Michnick.