Investigating Conformational Dynamics in Ligand and Temperature-Dependent Activation and Inhibition of TRPM8 and TRPV1

The ability to detect and respond to changes in temperature is a widely conserved phenomenon critical for mammalian survival. In humans, two Transient Receptor Potential (TRP) ion channels, TRP vanilloid 1 (TRPV1) and TRP melastatin 8 (TRPM8), have been identified as key thermosensors, activated by heat and cold, respectively. These ion channels are expressed across various tissues and play crucial roles in pain perception, thermoregulation, and pathophysiology conditions such as chronic pain and cancer. However, despite extensive progress, the development of drugs targeting these channels has been limited by significant on-target side effects, particularly involving intolerable thermosensation and disruption in thermoregulation. This dissertation investigates the role of protein dynamics in the function and modulation of TRPM8 and TRPV1. While TRPM8 and TRPV1 differ structurally, they share a well-conserved transmembrane domain (TMD) composed of six transmembrane helices (S1-S6) that form two self-contained subdomains: a pore domain (PD; S1-S4) and a voltage-sensing-like domain (VSLD; S5-S6). Functional and structural studies show that TMD is important for ligand and temperature activation. Biophysical techniques and cheminformatics were employed to probe human TRPM8-VSLD and TRP-targeting small chemical compounds to reveal a correlation between ligand chemical structure, protein dynamics, and cellular function. In addition, the human TRPV1-PD was isolated and reconstituted into lipid nanodiscs and probed using 19F to determine heat, pH, Double-Knot Toxin (DkTx), and ruthenium red (RR) sensitivity. Overall, this work emphasizes the importance of protein dynamics in mediating the functional outcomes of ion channels and other proteins.