TRPs et al.: a molecular toolkit for thermosensory adaptations

Abstract

The ability to sense temperature is crucial for the survival of an organism. Temperature influences all biological operations, from rates of metabolic reactions to protein folding, and broad behavioral functions, from feeding to breeding, and other seasonal activities. The evolution of specialized thermosensory adaptations has enabled animals to inhabit extreme temperature niches and to perform specific temperature-dependent behaviors. The function of sensory neurons depends on the participation of various types of ion channels. Each of the channels involved in neuronal excitability, whether through the generation of receptor potential, action potential, or the maintenance of the resting potential have temperature-dependent properties that can tune the neuron's response to temperature stimuli. Since the function of all proteins is affected by temperature, animals need adaptations not only for detecting different temperatures, but also for maintaining sensory ability at different temperatures. A full understanding of the molecular mechanism of thermosensation requires an investigation of all channel types at each step of thermosensory transduction. A fruitful avenue of investigation into how different molecules can contribute to the fine-tuning of temperature sensitivity is to study the specialized adaptations of various species. Given the diversity of molecular participants at each stage of sensory transduction, animals have a toolkit of channels at their disposal to adapt their thermosensitivity to their particular habitats or behavioral circumstances.

CNGA3 acts as a cold sensor in hypothalamic neurons

“…Our data suggest that the CNGA3 sensor likely exists in POA neurons not only as a homomer, but also as a heteromer with CNGB1 (Dai et al, 2013;Peng et al, 2004;Zhong et al, 2003). Although the apparent activation threshold for homomeric CNGA3 is lower than the physiological brain temperature, it may depend on the cellular environment and recording conditions, similar to other thermo-sensitive channels (Hoffstaetter et al, 2018;Song et al, 2016;Tan and McNaughton, 2016;Tominaga et al, 1998). The temperature sensitivity of hypothalamic neurons is plastic and is modulated by metabolic state, circadian cycle, oxygenation, inflammatory status and peripheral nutrient signals (Bartfai and Conti, 2012;Glotzbach and Heller, 1984;Pierau et al, 1998;Tattersall and Milsom, 2009).…”

Heat Waves, the New Normal: Summertime Temperature Extremes Will Impact Animals, Ecosystems, and Human Communities

“…Across animals with different thermal optima, orthologs of temperature-sensitive thermoTRP channels are thermally "tuned" to a particular range of temperatures (106). Thus variation in the specific TRP proteins expressed can shift the temperature thresholds for gene expression responses (45,60,106). Shifts in gene expression may regulate levels of proteins that confer thermoprotection, such as HSPs, or shift the thermal properties of proteins through expression of different protein isoforms.…”

The neural circuits of thermal perception

“…In recent years, the identification of the transient receptor potential (TRP) family of thermally sensitive ion channels in primary sensory afferent neurons [ 32 , 33 , 34 ], has provided a genetic access point to the thermal system. The thermal activation thresholds of TRP channels span the environmental temperature range and it is becoming increasingly evident they are co-expressed in adult primary sensory neurons [ 35 , 36 , 37 ].…”