Regulation of chemokine receptor signaling

PROJECT SUMMARY G protein-coupled receptor (GPCR) signaling plays an essential role in many physiological processes and is also involved in many human diseases, yet the mechanisms governing GPCR signaling remain poorly understood. The goal of the proposed research is to further our mechanistic understanding of GPCR signaling. The model GPCR receptor we study is the therapeutically relevant C-X-C chemokine receptor 4 (CXCR4). CXCR4 signaling is important for embryogenesis, immune function and stem cell regulation, among other functions. In addition, CXCR4 signaling is involved in several human diseases, including cancer. CXCR4 is aberrantly expressed in many cancers and its expression correlates with poor prognosis. This is mainly because CXCR4 signaling contributes to metastatic disease, the reason for most cancer related deaths. Yet the mechanisms governing CXCR4 signaling remain poorly understood. To achieve our goal, we will address two main questions: 1. What are the biophysical and structural determinants driving GPCR signaling by β-arrestins via non-GPCR binding partners? 2. What are the roles of PKCd and A-kinase anchoring proteins (AKAPs) in compartmentalized heterologous regulation of GPCR signaling? To address these questions, we will mainly use cell culture models and reconstitution assays using several complimentary integrative approaches including biophysical, biochemical, proximity ligation, multi-labeling fluorescence confocal microscopy, live cell imaging, and signaling assays. We believe our research is significant because we expect to define new concepts that apply broadly across the GPCR family, which will provide an advanced explanation of the mechanisms driving GPCR signaling. Our research hold the promise to translate new knowledge into innovative drug discovery efforts to modulate GPCR signaling therapeutically.