Dear Colleagues and Students,
You are cordially invited to the departmental seminar:
Title: “A molecular genetic system reveals distinct and redundant functions in PI3K pathway”
Speaker: Onur Cizmecioglu, PhD
Time: March 20th, Wednesday at 15:40
Host: Bahar Değirmenci Uzun
Abstract: The plasma membrane is the major site of phosphoinositide 3-kinase (PI3K) activation and integration of divergent growth factor signals. We aimed to understand how compartmentalization in the plasma membrane might contribute to the functions of the ubiquitous class IA PI3K isoforms, p110a and p110β utilizing a molecular genetic system. We found that p110β localizes to membrane rafts in a Rac1-dependent manner. This localization potentiates Akt activation by G-protein-coupled receptors (GPCRs). In contrast, p110α, which does not play a physiological role in GPCR signaling, is found to reside in nonraft regions of the plasma membrane. Notably, we depicted that p110β dependent, PTEN null tumor cells critically rely upon raft-associated PI3K activity. Collectively, our findings provide a mechanistic account of how membrane raft localization regulates differential activation of distinct PI3K isoforms and offer insight into why PTEN-deficient cancers depend on p110β. At the end of my talk I will try to illustrate how molecular genetics can be further implemented to dissect isoform specific functions in PI3K signaling.