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Emerging Concepts in Ion Channel Biophysics
Thursday Speaker Abstracts
26
Temperature-dependent Gating in Ion Channels
Feng Qin
.
State University of New York at Buffalo, Buffalo, NY, USA.
Mammals involve specific sensory neurons for pain and thermal sensation. Recent discoveries of
transient receptor potential (TRP) channels have unraveled a group of thermal TRP channels that
are responsible for transduction of physiologically relevant temperatures as well as detection of
chemical cues especially those correlated to thermal perception (e.g. capsaicin, the hot ingredient
of chili peppers, menthol, a cooling compound from mint, and oregano, savory and thyme, the
warmth-producing spices). Thermal TRP channels are directly activated by temperature and
exhibit unprecedented strong temperature dependence, some of which reach a Q10 value as large
as 100, as compared to a value of 2-3 for most ion channels. The strong temperature dependence
of thermal channels results from a large enthalpy change between closed and open states, about
five times that of ligand- or voltage-gated channels. But how and where thermal TRP channels
attain the large energetic has long been a mystery. We have investigated, by unique fast
temperature jumps, the heat activation of vanilloid receptors (TRPV1-4) and have explored the
biophysics and molecular basis underlying temperature sensing by the channels. This lecture will
present our understanding of mechanisms of temperature-dependent gating in ion channels and
will discuss critical issues and challenges facing the study of thermal channels.