G protein-coupled receptors (GPCRs) are the largest family of membrane receptors in human and have emerged as the largest family of drug targets with more than 35% of all drugs on the market functioning through GPCRs. Despite their desirability, to date, many GPCR families remain undrugged, partly due to lack of mechanistic knowledge about their activation and modulation. Metabotropic glutamate receptors (mGluRs) are members of class C GPCRs and are critical modulators of glutamate signaling. Due to their widespread expression in tissue and their central role they are among the most promising drug targets for the neurological disorders such as fragile X syndrome, epilepsy, anxiety, schizophrenia as well as some cancers. Advances in protein engineering and functional, structural and computational methods in the past twenty years have provided insights into the architecture, signaling and expression patterns of mGluRs. However, a general model of how ligands change the shape of mGluRs and how this conformational change is relayed across the membrane and over 12 nm to activate specific signaling pathways is poorly understood. In this research we will develop a novel technology that will allow us to watch a single mGluR protein while functioning in physiological conditions, in real time. This will allow us to quantify the motions of different domains of the receptor that are involved in signaling. Next, we will employ this approach to study how synthetic modulators of mGluR signaling affect protein conformation and dynamics to cholesterol and affect receptor signaling. This is a multi-disciplinary proposal where state-of-the-art in vitro single-molecule FRET (smFRET) spectroscopy is complemented by live-cell imaging, protein engineering and biophysical and biochemical methods. Once accomplished, the proposed research could provide a critical step towards rational design of efficient drugs with fewer undesirable side effects. Furthermore, these studies will provide a general roadmap for quantitative high-resolution structure-function studies of mammalian membrane proteins.

Public Health Relevance

Metabotropic glutamate receptors (mGluRs) are central regulators of glutamate signaling in the brain and are currently considered key drug targets for neurological disorders such as autism, anxiety, schizophrenia, Parkinson's disease, and addiction. The proposed research will apply cutting-edge methodologies that will allow us to directly watch receptors as they interact with ligands and function, to learn about how they function, with unprecedented accuracy. This knowledge may hold the key for the development of effective therapeutics for difficult-to-treat human diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM140272-01
Application #
10100895
Study Section
Biophysics of Neural Systems Study Section (BPNS)
Program Officer
Koduri, Sailaja
Project Start
2020-09-15
Project End
2025-08-31
Budget Start
2020-09-15
Budget End
2021-08-31
Support Year
1
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
160079455
City
Chicago
State
IL
Country
United States
Zip Code
60611