Jessica Bonnar L&S Sciences
Investigating the role of Ras proteins in TORC2 localization in Saccharomyces cerevisiae
In eukaryotes, an essential growth regulator is a multi-subunit, plasma membrane(PM)-associated protein kinase, the Target of Rapamycin Complex 2 (or TORC2). Work using Saccharomyces cerevisiae has established that TORC2 is responsible for controlling processes that preserve PM homeostasis and that regulate actin polymerization. Studies have shown that the localization of TORC2 to the plasma membrane is essential for the complex’s function. However, little is understood about the processes that regulate the assembly, maintenance and activity of TORC2 itself. Avo3, a TORC2 subunit necessary for maintaining stability of the complex, contains a RasGEFN domain, a structural motif typically found in Ras guanine nucleotide exchange factors (GEFs). Ras proteins themselves are anchored to the PM via modification of their C-terminal end. Therefore, the RasGEFN domain of Avo3 may contribute to PM localization of yeast TORC2. My primary goal this summer is to use genetic methods and fluorescence microscopy to investigate the potential roles of the RasGEFN domain in Avo3 and the two Ras proteins of S. cerevisiae in targeting and maintaining TORC2 at the PM.