QB3 Postdoc Seminar: Role of phosphoinositides and individual subunits in the assembly state, and localization of the Saccharomyces cerevisiae TORC2 complex

Seminar | February 2 | 4:30-5:30 p.m. | 621 Stanley Hall

 Nieves Martinez Marshall (Thorner lab)

 QB3 - California Institute for Quantitative Biosciences

The ability to maintain homeostasis of the cell surface area in response to environmental insults and intracellular changes in lipid metabolism is essential for eukaryotic cell survival. A key regulator of membrane homeostasis in Saccharomyces cerevisiae is TORC2, a multiprotein complex that contains the evolutionarily conserved protein kinase Target of Rapamycin (TOR). The localization of TORC2 to the plasma membrane is essential for cell viability, and requires the Pleckstrin Homology (PH) domain of the Avo1 subunit, which specifically binds plasma membrane phosphatidylinositol 4,5-bisphosphate PI(4,5)P2 (PIP2). This raises the question of whether PIP2 is an essential general regulator of TORC2. Moreover, how TORC2 assembles at the plasma membrane and forms higher order oligomers is poorly understood. Here we use an auxin-inducible degradation system to deplete single subunits to analyze the dynamics of TORC2 assembly, and investigate the role of PIP2 in TORC2 regulation. Our studies reveal the intriguing possibility that additional factors other than the PH domain of Avo1 and PIP2 contribute to the docking of TORC2 to the plasma membrane.

For the presentation-skill practicing session, we would like to provide pizza to the attendee who signed up, so please RSVP through this link before next TUESDAY. )

 swchou@berkeley.edu