Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Selective disruption of high sensitivity heat activation but not capsaicin activation of TRPV1 channels by pore turret mutations

Selective disruption of high sensitivity heat activation but not capsaicin activation of TRPV1... The capsaicin receptor transient receptor potential vanilloid (TRPV)1 is a highly heat-sensitive ion channel. Although chemical activation and heat activation of TRPV1 elicit similar pungent, painful sensation, the molecular mechanism underlying synergistic activation remains mysterious. In particular, where the temperature sensor is located and whether heat and capsaicin share a common activation pathway are debated. To address these fundamental issues, we searched for channel mutations that selectively affected one form of activation. We found that deletion of the first 10 amino acids of the pore turret significantly reduced the heat response amplitude and shifted the heat activation threshold, whereas capsaicin activation remained unchanged. Removing larger portions of the turret disrupted channel function. Introducing an artificial sequence to replace the deleted region restored sensitive capsaicin activation in these nonfunctional channels. The heat activation, however, remained significantly impaired, with the current exhibiting diminishing heat sensitivity to a level indistinguishable from that of a voltage-gated potassium channel, Kv7.4. Our results demonstrate that heat and capsaicin activation of TRPV1 are structurally and mechanistically distinct processes, and the pore turret is an indispensible channel structure involved in the heat activation process but is not part of the capsaicin activation pathway. Synergistic effect of heat and capsaicin on TRPV1 activation may originate from convergence of the two pathways on a common activation gate. Submitted: 23 September 2011 Accepted: 15 February 2012 This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms ). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/ ). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of General Physiology Rockefeller University Press

Selective disruption of high sensitivity heat activation but not capsaicin activation of TRPV1 channels by pore turret mutations

Download PDF
11 pages

Loading next page...
 
/lp/rockefeller-university-press/selective-disruption-of-high-sensitivity-heat-activation-but-not-o0CkbW1dT8

References (112)

Publisher
Rockefeller University Press
Copyright
© 2012 Cui et al.
ISSN
0022-1295
eISSN
1540-7748
DOI
10.1085/jgp.201110724
pmid
22412190
Publisher site
See Article on Publisher Site

Abstract

The capsaicin receptor transient receptor potential vanilloid (TRPV)1 is a highly heat-sensitive ion channel. Although chemical activation and heat activation of TRPV1 elicit similar pungent, painful sensation, the molecular mechanism underlying synergistic activation remains mysterious. In particular, where the temperature sensor is located and whether heat and capsaicin share a common activation pathway are debated. To address these fundamental issues, we searched for channel mutations that selectively affected one form of activation. We found that deletion of the first 10 amino acids of the pore turret significantly reduced the heat response amplitude and shifted the heat activation threshold, whereas capsaicin activation remained unchanged. Removing larger portions of the turret disrupted channel function. Introducing an artificial sequence to replace the deleted region restored sensitive capsaicin activation in these nonfunctional channels. The heat activation, however, remained significantly impaired, with the current exhibiting diminishing heat sensitivity to a level indistinguishable from that of a voltage-gated potassium channel, Kv7.4. Our results demonstrate that heat and capsaicin activation of TRPV1 are structurally and mechanistically distinct processes, and the pore turret is an indispensible channel structure involved in the heat activation process but is not part of the capsaicin activation pathway. Synergistic effect of heat and capsaicin on TRPV1 activation may originate from convergence of the two pathways on a common activation gate. Submitted: 23 September 2011 Accepted: 15 February 2012 This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms ). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/ ).

Journal

The Journal of General Physiology – Rockefeller University Press

Published: Apr 1, 2012

There are no references for this article.