HaloTag-based approach to quantify subcellular localization of TRPV3 channels

Area of Science:

• Molecular Biology
• Cell Biology
• Biophysics

Background:

• The TRPV3 channel is vital for skin barrier function and hair growth, with its dysfunction implicated in conditions like atopic dermatitis and Olmsted syndrome.
• Current understanding of endogenous TRPV3 channel regulation is limited, and experimental tools for quantifying cell surface expression are lacking, especially in live cells.

Purpose of the Study:

• To develop and validate a novel tool for reliably quantifying TRPV3 channel cell surface expression and localization in live and fixed cells.
• To investigate the impact of N-terminal truncation and TMEM79 co-expression on TRPV3 channel localization.

Main Methods:

• Fusion of a cpHaloTag to the extracellular face of the mouse TRPV3 channel (Halo-TRPV3).
• Sequential labeling with membrane-permeable and impermeable HaloTag dyes for differential detection of surface vs. intracellular channels.
• Confocal and epifluorescence microscopy, flow cytometry, and co-expression with fluorescent reporters for Ca2+ activity and organellar markers.

Main Results:

• The Halo-TRPV3 fusion protein retains functional sensitivity to heat, voltage, and agonists.
• Robust changes in TRPV3 cell surface localization were detected upon N-terminal truncation or TMEM79 co-expression.
• The tool enables quantification of localization changes via epifluorescence microscopy and flow cytometry, suitable for high-throughput screening.

Conclusions:

• The developed Halo-TRPV3 tool is practical and sensitive for studying TRPV3 channel function and regulation.
• This tool facilitates elucidation of molecular and cellular mechanisms underlying TRPV3 channel activity and localization.
• The system can be adapted to assess channel activity and organellar trafficking, offering broad applications in cell biology research.