Diverse membrane affinities of G? members deferentially modulate the G?? effectors and cell behaviors - Project Summary/Abstract
G protein coupled receptors (GPCRs) control the majority of cellular signaling; both physiological and pathological.
Activated GPCRs induce heterotrimer dissociation, generating active GαGTP and Gβγ. Generated Gβγ controls effectors in
multiple signaling pathways. GPCRs and G proteins based chemokine pathway is crucial for proper cellular functions
including migration and growth and is highly implicated diseases including cancer. Cancer cells employ chemokine pathway
to hijack growth factor receptor (GFR) signaling, primarily through Gβγ, which has the propensity to control cell adhesion,
migration and invasion, facilitating metastasis. Although there are 48 members in the family, Gβγ is often considered a
unitary signaling entity. However, our provocative data show that, the 12 Gγ types differently govern the PM affinity of
Gβγ, regulating the efficacy of Gβγ signaling in a Gγ identity dependent manner.
In Aim 1, we will establish molecular mechanisms that allow Gγ subunits to possess their carboxy terminus (CT)
identity specific PM affinities. In Aim 2, we will seek mechanisms by which PM affinity of Gγ subunits control the efficacy
of Gβγ effector activation and regulation of chemokine signaling in triple negative breast cancer (TNBC) cells. In Aim 3 of
the proposal, we will examine the role of PM affinity of Gγ and hence he PM-bound fraction of free Gβγ in regulation of
signaling that govern adhesion, migration and invasion of TNBC cells.
This project is designed to train and employ undergraduate and graduate students, and uses innovative subcellular
optogenetic methods to control signaling, high resolution confocal as well as total internal reflection fluorescence (TIRF)
microscopy to monitor signaling and cell behaviors, novel–unbiased image and data analysis methods to extract data, state-
of-the-art genome editing methods to alter the PM affinity of native Gγ in TNBC cells. The proposed work will provide the
first analysis of GPCR-G protein signaling regulation by the Gγ subtype specific PM affinities of Gβγ in breast cancer cells.
Our goal is to deliver the molecular process that controls Gγ-PM interactions as a new molecular target governing cancer
cell adhesion, migration and proliferation.
