Pathway-dependent cold activation of heat-responsive TRPV channels

Area of Science:

• Molecular Biology
• Biophysics
• Computational Biology

Background:

• Thermosensitive Transient Receptor Potential Vanilloid (TRPV) channels (TRPV1-4) are crucial for sensory neurons' response to heat.
• The precise heat sensors and activation triggers for these channels, especially under cold conditions, remain largely uncharacterized.

Purpose of the Study:

• To computationally investigate the cold activation mechanisms of TRPV channels.
• To compare the cold activation pathways of a minimal TRPV1 construct with full-length human TRPV3.
• To identify conserved structural elements and pathways involved in thermosensation.

Main Methods:

• Utilized computational modeling to simulate cold activation of TRPV1 and TRPV3.
• Analyzed activation pathways, focusing on intersubunit interactions near the lower gate.
• Compared temperature sensitivity and activation thresholds between different channel constructs.

Main Results:

• Cold activation of minimal TRPV1 followed a pathway from a putative heat activation starter.
• Full-length TRPV3 exhibited a distinct activation pathway, originating away from the assumed heat activation point.
• Disruption of conserved intersubunit interactions near the lower gate was essential for channel opening.
• TRPV1 demonstrated mirrored thermosensitivity and matched thresholds with heat activation, unlike TRPV3.

Conclusions:

• The study provides insights into the conserved mechanisms underlying cold activation in TRPV channels.
• Mirrored thermosensitivity and matched thresholds can help pinpoint the primary thermal sensors in TRPV1 and TRPV3.
• This approach can be extended to elucidate the thermal sensing mechanisms of TRPV2 and TRPV4.