Optical control of PIEZO1 channels

Area of Science:

• Biophysics
• Molecular Biology
• Neuroscience

Background:

• PIEZO proteins are large, mechanically-activated ion channels crucial for cellular mechanotransduction.
• Optogenetic tools, like photoswitchable azobenzenes, have enabled optical control of other ion channels, such as purinergic P2X receptors.
• Extending optogenetics to mechanically-activated channels offers precise, non-mechanical methods to study their function.

Purpose of the Study:

• To engineer a light-gated PIEZO1 channel for optical control of its gating mechanism.
• To investigate if the light-gated PIEZO1 channel retains native mechanical activation properties.
• To explore the utility of azobenzene-based photoswitches for controlling large, mechanically-activated ion channels.

Main Methods:

• Site-directed mutagenesis to introduce a cysteine at Y2464 (Y2464C) on the extracellular side of transmembrane helix 38.
• Covalent tethering of an azobenzene-based photoswitch to the engineered cysteine.
• Characterization of channel gating using 365-nm light irradiation and comparison with mechanical stimulation.

Main Results:

• A light-gated mouse PIEZO1 channel (Y2464C) was successfully engineered, rapidly gating upon 365-nm light exposure.
• The light-induced gating mimicked the functional properties of mechanically-activated PIEZO1 channels.
• Light-evoked molecular motions within the channel were comparable to those induced by mechanical forces.

Conclusions:

• Azobenzene-based optogenetics can be effectively extended to control unusually large, mechanically-activated ion channels like PIEZO1.
• This engineered light-gated PIEZO1 channel provides a novel tool for precise, non-invasive interrogation of PIEZO1 function.
• The study advances chemical optogenetics for studying mechanotransduction pathways.