Evolution of heat receptors in animals

Animals on Earth adapt themselves to temperature changes such as desert heat, or ice cold weather. However, the molecular mechanism of adaptation to these thermal environments during evolution related to thermal receptors has not been clearly understood.

Professor Makoto Tominaga and assistant Shigeru Saito demonstrated that the molecule is called TRP channels, acting as receptors in animals, sensing different temperatures in mammals to species. Western clawed frogs, even molecules similar to TRP channels were tested. These observations show that these receptors can dynamically alter their thermal sensitivities to adapt to environments with extreme temperatures during evolution. The study was published in the online journal PLoS Genetics (PLoS Genetics). The research is a collaboration of Professor Ryuzo Shingai at Iwate University.

The study used western clawed frogs ( Xenopus tropicalis ) living in the tropics. The appropriate temperature for this species is about 26 ^o C and the temperature below 20-18 ^o C will cause an adverse reaction. The team has identified the gene TRPV3, known as a hot temperature sensor in mammals, and in this frog species tested functionally.

Western clawed frog ( Xenopus tropicalis )

Researchers discovered temperature sensitivity of TRPV3 in frogs other than TRPV3 in mammals . Mammal TRPV3 channels are activated by high temperatures - heat (33-39 ^o C and higher), but this channel in frogs is activated by low temperature - cold (16 ^o C and lower). Therefore, western clawed frogs perceive unfavorable low temperatures with heat receptors. In addition to differences in heat sensitivity, the amino acid sequence of TRPV3 channel varies greatly between western clawed frogs and mammals at the ends of channels located in the oocytes. Structural differences related to differences in heat sensitivity of TRPV3 channel. On the other hand, mammalian TRPV3 channel is activated by a number of chemical compounds, while TRPV3 channel in frogs with western claws is not activated by such compounds except one, so the Chemical compatibility of TRPV3 channel is also different among frogs and mammals.

Professor.Tominaga said: ' We studied the evolution of TRPV channel genes that act as receptors in vertebrates, and found that this group of genes was created by diversity. vertebrate animals. Changes in thermophilic evolution involve adapting to ambient temperatures or because of changes in physiological characteristics that are not well known. Here we have unraveled one of the molecular mechanisms of functional change - ' Variable model ' in heat receptors. Research results show that channels TRPV3 form sensitive against the impact of temperature in the evolution of terrestrial vertebrates. In contrast, this suggests that the heat sensitivity of TRP channels is unstable but can be flexibly transformed, even reversed in some cases, during evolution to adapt to ambient temperatures . '