Gating of thermally activated channels

Area of Science:

• Neuroscience
• Molecular Biology
• Biophysics

Background:

• Specialized neurons in the skin utilize ion channels from the transient receptor potential (TRP) superfamily as temperature detectors.
• TRP channels are classified into subfamilies: TRPC, TRPM, TRPA, and TRPV, with some responding to heat and others to cold.

Purpose of the Study:

• To elucidate the structure, function, and gating mechanisms of thermal TRP channels.
• To identify the molecular determinants responsible for temperature sensitivity in these channels.

Main Methods:

• Characterization of macroscopic currents and single-channel analysis.
• Identification of molecular determinants of temperature sensitivity in specific channels (e.g., TRPV1, TRPA1, TRPV3).

Main Results:

• Thermal TRP channels are polymodal, responding to temperature, voltage, pH, lipids, and agonists.
• High temperature sensitivity is attributed to a large enthalpy change (∼100 kcal/mol).
• Temperature gating is complex, best modeled by branched or allosteric mechanisms with multiple states.

Conclusions:

• The molecular determinants of temperature sensitivity reside within specific protein domains.
• Thermal TRP channels are crucial for thermosensation and exhibit complex, multi-state gating mechanisms.