The canonical transient receptor potential channel 3 (TRPC3) plays key roles in GPCR signaling and is linked to several diseases, including cardiac arrhythmias, cancer, and neurodegeneration. Despite advances in cryo-EM, existing structures show TRPC3 only in its closed state, leaving the open-pore conformation unresolved.

Importantly, TRPC3 is highly sensitive to its lipid environment. Lipids such as diacylglycerol (DAG), cholesterol, and PIP₂ directly influence its gating and stability. When removed from these native lipid interactions, TRPC3 often loses function or remains closed — a major barrier for structural studies.

In a new study, researchers from the University of Graz and collaborators in Austria and France addressed this challenge by testing different cell systems and extraction agents to purify functional TRPC3 while preserving its lipid environment. They compared adherent HEK293, Expi293F, and K. phaffii yeast cells, evaluating traditional detergents (DDM, LMNG, FOS-choline) and nanodisc-forming agents (DIBMA, Carboxy-DIBMA, DDDG).

Key findings:

• Expi293F cells produced the highest yield of TRPC3.

• DDDG and DDM best preserved structure and function under native-like conditions.

• Negative-stain EM confirmed the purified protein retained its tetrameric “flower-shaped” assembly.

• Electrophysiology showed that purified and reconstituted TRPC3 channels remained functional, with conductance and gating behavior comparable to those in cells (bilayer recordings performed using the Orbit mini).

These results demonstrate that TRPC3 can be stably purified in nanodiscs or mild detergents without losing activity. This provides robust conditions for future cryo-EM studies to finally capture TRPC3 in its open state, deepening our understanding of its function and therapeutic potential.

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📖 Read the full article: Utilizing native nanodiscs to isolate active TRPC3 channels and expand structural analysis capabilities (Scientific Reports, 2025)

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