Thermal actuation in TRPV1: Role of embedded lipids and intracellular domains.

The transient response potential cation channel TRPV1 responds to high temperature, but many of the mechanisms driving its thermal actuation remain unclear. Its recently resolved structure has enabled a number of molecular dynamics (MD) studies focused on illuminating these mechanisms. We add to these efforts by performing the first all-atom MD simulations of its most recently resolved structure at different temperatures. While the complete, thermally induced transition of TRPV1 from its closed to open configuration remains elusive, our analysis of the hydrogen bonding networks, thermodynamics, hydration, and principal components of motion provide a wealth of information on the mechanisms which initiate or influence the thermal opening in TRPV1. In particular, we (i) support the previously proposed mechanism driving thermal actuation in the extracellular pore of TRPV1, (ii) present new hypotheses regarding the thermal actuation in the C-terminal and adjacent linker domains, and (iii) support and build upon the existing hypothesis regarding the role of the vanilloid binding pocket and lipids embedded therein.