Probing Mechanisms Of Temperature Sensitivity Of Thermo-Trps

The sense of touch is unique in perceiving stimuli both physical (temperature, mechanical) and chemical (compounds that cause pain, itch, et cetera) in nature. Recently, we and others have identified and characterized molecules responsible for sensing environmental temperature. These proteins are ion channels activated by distinct changes in thermal energy (in the noxious to innocuous range), thus functioning as the molecular thermometers of our body. To date, the mechanism underlying thermal activation of TRP channels represents a fundamental unknown in the field. As might be expected, thermoTRPs are steeply temperature dependent. While most enzymatic processes have a Q10 of 2-4, thermoTRPs have Q10 values as high as 20. Temperature activation of most thermoTRPs is retained in cell-free membranes, arguing for a mechanism independent of cytoplasmic processes. We have developed a novel high-throughput random mutagenesis screen to identify residues required for the modulation of ion channels or receptors. We are applying this method to isolate thermoTRP temperature-insensitive mutants. Our near-term goal is to catalog all amino acids of thermoTRPs required for thermal activation. Ultimately, we aim to explain the mechanism by which temperature leads to pore-opening.